Form 424B5

PROSPECTUS SUPPLEMENT

(To Prospectus dated August 23, 2016)

2,127,660 Shares

Common Stock

We are offering 2,127,660 shares of our common stock, par value $0.001 per share, pursuant to this prospectus supplement and the accompanying prospectus.

Our common stock is listed on The NASDAQ Capital Market under the symbol “RTTR.” On October 24, 2016, the last reported sale price of our common stock was $3.20 per share. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities in a public primary offering with a value of more than one-third of the aggregate market value of our common stock held by non-affiliates in any twelve-month period, so long as the aggregate market value of our common stock held by non-affiliates remains below $75,000,000. We have not offered any securities pursuant to General Instruction I.B.6 of Form S-3 during the twelve calendar months prior to and including the date of this prospectus.

Our business and an investment in our securities involve a high degree of risk. See “Risk Factors” beginning on page S-3 of this prospectus supplement for a discussion of information that you should consider before investing in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

	Per Share		Total
Public offering price..........................................................................................................................	$	2.35	$	5,000,001
Underwriting discounts and commissions ⁽¹⁾ ....................................................................................	$	0.1645	$	350,000
Proceeds, before expenses, to us.......................................................................................................	$	2.1855	$	4,650,001

(1) See “Underwriting” beginning on page S-8 of this prospectus supplement for a description of compensation payable to the underwriters.

We have granted a 30-day option to the underwriters to purchase up to 212,766 additional shares of common stock solely to cover over-allotments, if any. If the underwriters exercise the option in full, the total underwriting discounts and commissions payable by us will be $385,000 and the total proceeds to us, before expenses, will be $5,115,001 .

The underwriters expect to deliver the shares against payment therefor on or about October 31 , 2016.

Aegis Capital Corp

October 26 , 2016

TABLE OF CONTENTS

Prospectus Supplement

	Page
About This Prospectus Supplement	S-ii
Where You Can Find More Information	S-ii
Incorporation of Information By Reference	S-iii
Cautionary Note Regarding Forward-Looking Statements	S-iii
Prospectus Supplement Summary	S-1
Risk Factors	S-3
Use of Proceeds	S-4
Price Range of Our Common Stock	S-5
Dividend Policy	S-5
Capitalization	S-6
Dilution	S-7
Underwriting	S-8
Legal Matters	S-11
Experts	S-11

Prospectus

About This Prospectus	ii
Prospectus Summary	1
Risk Factors	2
Cautionary Note Regarding Forward-Looking Statements	3
Ratio of Earnings to Fixed Charges	4
Use of Proceeds	4
Plan of Distribution	6
Description of Capital Stock	8
Description of Debt Securities	11
Description of Warrants	13
Description of Rights	14
Description of Purchase Contracts	15
Description of Units	16
Legal Matters	17
Experts	17
Where You Can Find More Information	17
Incorporation of Information By Reference	18

S- i

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is the prospectus supplement, which describes the terms of this offering and also adds to and updates the information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus concerning Ritter Pharmaceuticals, Inc. The second part is the accompanying prospectus, dated August 23, 2016, including the documents incorporated by reference therein, which provides more general information, some of which may not apply to this offering. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. If the description of this offering or other information varies between the prospectus supplement, on the one hand, and the accompanying prospectus, or in any document incorporated by reference that was filed with the Securities and Exchange Commission, or the SEC, before the date of this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. We may also authorize one or more “free writing prospectuses” (i.e., written communications concerning the offering that are not part of this prospectus supplement) that may contain certain material information relating to this offering. Before you invest in the common stock offered under this prospectus supplement, you should carefully read both this prospectus supplement and the accompanying prospectus together with additional information under the heading “Where You Can Find More Information” and “Incorporation of Certain Documents by Reference.”

You should rely only on the information contained or incorporated by reference in this prospectus supplement and in the accompanying prospectus or any free writing prospectus that we may provide. We have not authorized anyone to provide you with different information. If anyone provides you with different or additional information, you should not rely on it. You should not assume that the information contained in this prospectus supplement, the accompanying prospectus, any free writing prospectus that we may provide or any document incorporated by reference is accurate as of any date other than the date mentioned on the cover page of these documents. Our business, financial condition, results of operations and prospects may have changed since those dates. We are not making offers to sell the securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation.

References in this prospectus supplement and the accompanying prospectus to the terms “we,” “us,” “our” “Ritter” or “the Company” or other similar terms mean Ritter Pharmaceuticals, Inc. and its consolidated subsidiaries, unless we state otherwise or the context indicates otherwise.

WHERE YOU CAN FIND MORE INFORMATION

We are subject to the information and reporting requirements of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and, in accordance with this law, file periodic reports, proxy statements and other information with the SEC. These periodic reports, proxy statements, and other information are available for inspection and copying at the SEC’s public reference facilities at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. Information on the public reference facilities may be obtained by calling the SEC at 1-800-SEC-0330. In addition, the SEC maintains a website that contains reports, proxy and information statements and other information that is filed through the SEC’s EDGAR System. The website can be accessed at http://www.sec.gov.

We also maintain a website at www.ritterpharmaceuticals.com. You may access our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act with the SEC free of charge at our website as soon as reasonably practicable after such material is electronically filed with, or furnished to, the SEC. The information contained in, or that can be accessed through, our website is not a part of this prospectus supplement or the accompanying prospectus, and the reference to our website does not constitute incorporation by reference into this prospectus supplement or the accompanying prospectus of the information contained at that site, other than documents that we file with the SEC that are incorporated by reference into this prospectus supplement and the accompanying prospectus.

S- ii

INCORPORATION OF INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information that we file with them. Incorporation by reference allows us to disclose important information to you by referring you to those other documents. The information incorporated by reference is an important part of this prospectus supplement and the accompanying prospectus, and information that we file later with the SEC will automatically update and supersede this information. This prospectus supplement and the accompanying prospectus omit certain information contained in the registration statement, as permitted by the SEC. You should refer to the registration statement and any prospectus supplement filed hereafter, including the exhibits, for further information about us and the securities we may offer pursuant to this prospectus supplement and the accompanying prospectus. Statements in this prospectus supplement regarding the provisions of certain documents filed with, or incorporated by reference in, the registration statement are not necessarily complete and each statement is qualified in all respects by that reference. Copies of all or any part of the registration statement, including the documents incorporated by reference or the exhibits, may be obtained upon payment of the prescribed rates at the offices of the SEC listed above in “Where You Can Find More Information.” The documents we are incorporating by reference are:

	●	our Annual Report on Form 10-K for the fiscal year ended December 31, 2015 filed on March 21, 2016 (the “2015 Form 10-K”);

	●	our Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 2016, filed on May 9, 2016, and June 30, 2016, filed on August 8, 2016;

	●	our Current Reports on Form 8-K filed on January 5, 2016 and June 6, 2016, and

	●	the description of the Company’s Common Stock contained in the Company’ Registration Statement on Form 8-A (File No. 1-37428) filed on June 15, 2015, including any amendment or report filed for the purpose of updating such description.

Cautionary Note Regarding FORWARD-LOOKING STATEMENTS

Some of the statements in this prospectus supplement and the accompanying prospectus constitute “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Exchange Act. These statements relate to future events concerning our business and to our future revenues, operating results and financial condition. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “forecast,” “predict,” “propose,” “potential” or “continue,” or the negative of those terms or other comparable terminology.

Any forward looking statements contained in this prospectus supplement or the accompanying prospectus are only estimates or predictions of future events based on information currently available to our management and management’s current beliefs about the potential outcome of future events. Whether these future events will occur as management anticipates, whether we will achieve our business objectives, and whether our revenues, operating results or financial condition will improve in future periods are subject to numerous risks. There are a number of important factors that could cause actual results to differ materially from the results anticipated by these forward-looking statements. These important factors include those that we discuss under the heading “Risk Factors” and in other sections of the 2015 Form 10-K, our Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2016 and June 30, 2016, all filed with the SEC, as well as in our Current Reports filed on Form 8-K from time to time with the SEC, that are incorporated by reference into this prospectus supplement and the accompanying prospectus. You should read these factors and the other cautionary statements made in this prospectus supplement, the accompanying prospectus and in the documents we incorporate by reference into this prospectus supplement as being applicable to all related forward-looking statements wherever they appear in this prospectus supplement or the documents we incorporate by reference into this prospectus supplement. If one or more of these factors materialize, or if any underlying assumptions prove incorrect, our actual results, performance or achievements may vary materially from any future results, performance or achievements expressed or implied by these forward-looking statements. We undertake no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

S- iii

PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights information contained elsewhere or incorporated by reference in this prospectus supplement and the accompanying prospectus. This summary does not contain all of the information you should consider before investing in our common stock. You should read this entire prospectus supplement, the accompanying prospectus and the documents incorporated by reference carefully, especially the section titled “Risk Factors” and our financial statements and related notes included or incorporated by reference in this prospectus supplement and the accompanying prospectus, before making an investment decision.

Overview

Ritter Pharmaceuticals, Inc. develops novel therapeutic products that modulate the human gut microbiome to treat gastrointestinal diseases. We are advancing human gut health research by exploring the metabolic capacity of the gut microbiota and translating the functionality of prebiotic-based therapeutics into applications intended to have a meaningful impact on a patient’s health. “Prebiotics” is a general term used to refer to chemicals that induce the growth and/or activity of commensal microorganisms that contribute to the well-being of their host.

Our first novel microbiome modulator, RP-G28, an orally administered, high purity galacto-oligosaccharide (a carbohydrate found naturally, at least in small amounts, in plants, consisting of three to ten simple sugars linked together), is currently under development for the reduction of symptoms associated with lactose intolerance. RP-G28, is designed to stimulate the growth of lactose-metabolizing bacteria in the colon, thereby effectively adapting the gut microbiome to assist in digesting the lactose that reaches the large intestine. RP-G28 has the potential to become the first drug approved by the U.S. Food and Drug Administration, or FDA, for the reduction of symptoms associated with lactose intolerance.

Recent Developments

Phase 2b/3 clinical trial of RP-G28

On October 17, 2016, we announced that the last patient has completed dosing and all monitoring visits in our Phase 2b/3 clinical trial of RP-G28 for the treatment of lactose intolerance. Topline results of the trial are expected to be announced in the first quarter of 2017. The Phase 2b/3 trial is a double-blind, placebo-controlled, three arm, multicenter study evaluating safety, efficacy and tolerability of two dosing regimens of RP-G28 in patients with moderate to severe lactose intolerance symptoms. Enrollment was initiated in March 2016 and completed in August 2016, achieving our projected enrollment time period. The study aims to evaluate a patient’s ability to consume dairy foods post-treatment with improved tolerance and reduced digestive symptoms. A total of 377 subjects were enrolled in the trial with 18 clinical sites participating throughout the United States. Patients underwent a 30-day treatment, followed by a 30-day post-treatment evaluation of dairy tolerance. A subset of subjects have been rolled into a 12-month extension study to evaluate long-term durability of treatment. The study will also evaluate each participant’s microbiome, expanding knowledge of the effects that RP-G28 may have on adapting the gut microbiota in a beneficial manner.

We have, as recently as this week, had communications with the FDA regarding our clinical program and regulatory path towards getting our product adequately studied and eventually approved. We intend to hold two meetings with the FDA in the near future about our Phase 2b/3 study, including a Type C meeting as well as an End of Phase 2 meeting, both of which the FDA has encouraged us to schedule. These meetings and communications are typical for development stage companies and include the clinical pathway, regulatory requirements, statistical plan and endpoints and similar matters.

Third Quarter 2016 Preliminary Cash and Liabilities

We estimate cash and cash equivalents to be approximately $8.5 million as of September 30, 2016. Total liabilities are expected to be approximately $3.8 million as of September 30, 2016. Compared to the second quarter, cash and cash equivalents decreased by approximately $2.3 million and total liabilities increased by approximately $1.1 million during the third quarter.

The financial data presented above are preliminary and subject to revision based upon our financial closing procedures and the completion of the review of our financial statements. We undertake no obligation to update or supplement the information provided above until we release our results of operations for the three and nine months ended September 30, 2016. Mayer Hoffman McCann P.C., our independent registered public accounting firm, has not audited, reviewed, compiled or performed any procedures with respect to this financial data.

Corporate Information

We were formed as a Nevada limited liability company on March 29, 2004 under the name Ritter Natural Sciences, LLC. On September 16, 2008, we converted into a Delaware corporation under the name Ritter Pharmaceuticals, Inc. Our principal executive offices are located at 1880 Century Park East, #1000, Los Angeles, CA 90067, and our telephone number is (310) 203-1000. Our website address is www.ritterpharmaceuticals.com. The information contained on, or that can be accessed through, our website is not part of this prospectus supplement or the accompanying prospectus.

S- 1

The Offering

Common stock offered by this prospectus supplement		2,127,660 shares (or 2,340,426 shares if the underwriters exercise their option to purchase additional shares in full).

Option to purchase additional shares		We have granted the underwriters a 30-day option to purchase up to 212,766 additional shares of our common stock to cover over-allotments, if any.

Common stock to be outstanding after this offering		10,730,362 shares (or 10,943,128 shares if the underwriters exercise their option to purchase additional shares in full).

Use of proceeds		We intend to use the net proceeds from this offering for our operations and for other general corporate purposes, including, but not limited to, our internal research and development programs and the development of new programs, general working capital and possible future acquisitions. See “Use of Proceeds” for a more detailed description of the intended use of proceeds from this offering.

Risk factors		See “Risk Factors” and other information included in this prospectus supplement, in the accompanying prospectus, as well as in our periodic reports filed with the SEC incorporated by reference in this prospectus supplement and the accompanying prospectus for a discussion of factors that you should consider carefully before deciding to invest in our common stock.

NASDAQ Capital Market symbol		RTTR

The number of shares of common stock to be outstanding after this offering is based on 8,602,702 shares of common stock outstanding as of October 25, 2016, and excludes as of such date:

	●	578,321 shares of common stock issuable upon exercise of outstanding warrants at a weighted average exercise price of $8.45 per share;

	●	2,455,924 shares of common stock issuable upon exercise of outstanding options as of October 25, 2016, at a weighted average exercise price of $6.04 per share, of which 1,478,180 shares are vested as of such date; and

	●	109,360 shares of common stock reserved for future issuance under the 2015 equity incentive plan (the “2015 Plan”).

S- 2

RISK FACTORS

Investing in our common stock involves a high degree of risk. Before deciding whether to invest in our common stock, you should carefully consider the risks described below and in the sections entitled “Risk Factors” in the prospectus to which this prospectus supplement forms a part, as well as the 2015 Form 10-K or our most recent Quarterly Report on Form 10-Q, as filed with the SEC, which are incorporated herein by reference in their entirety, as well as any amendment or updates to our risk factors reflected in subsequent filings with the SEC, including any applicable prospectus supplement. The occurrence of any of the events or developments described below could harm our business, financial condition, results of operations and prospects. In such an event, the market price of our common stock could decline, and you may lose all or part of your investment. Additional risks and uncertainties not presently known to us or that we currently deem immaterial also may harm our business, financial condition, results of operations and prospects.

Risks Related to this Offering

Management will have broad discretion as to the use of the net proceeds from this offering, and we may not use the proceeds effectively.

Our management will have broad discretion as to the application of the net proceeds and could use them for purposes other than those contemplated at the time of this offering. Our stockholders may not agree with the manner in which our management chooses to allocate and spend the net proceeds. Moreover, our management may use the net proceeds for corporate purposes that may not increase our market value.

Investors in this offering will experience immediate and substantial dilution.

The public offering price of the securities offered pursuant to this prospectus supplement may be substantially higher than the net tangible book value per share of our common stock. Therefore, if you purchase shares of common stock in this offering, you will incur immediate and substantial dilution in the pro forma net tangible book value per share of common stock from the price per share that you pay for such common stock. If the holders of outstanding options or other securities convertible into our common stock exercise those options or other such securities at prices below the public offering price, you will incur further dilution. See “Dilution” on page S-7 of this prospectus supplement for a more detailed discussion of the dilution you will incur in this offering.

Future sales of substantial amounts of our common stock could adversely affect the market price of our common stock.

Future sales of substantial amounts of our common stock, or securities convertible or exchangeable into shares of our common stock, into the public market, including shares of our common stock issued upon exercise of options and warrants, or perceptions that those sales could occur, could adversely affect the prevailing market price of our common stock and our ability to raise capital in the future. We also may offer and sell up to an aggregate of $10 million of shares of our common stock pursuant to a purchase agreement entered into with Aspire Capital Fund, LLC on December 18, 2015. As of September 30, 2016, we had 888,835 shares remaining available for sale under the purchase agreement with Aspire Capital. We have agreed with the underwriters to not sell any shares pursuant to this agreement for a period of 30 days from the pricing date of this offering .

S- 3

USE OF PROCEEDS

We estimate that the net proceeds from this offering will be $4,400,001 (or approximately $4,865,001 if the underwriters exercise their option to purchase additional shares from us in full), after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

We anticipate that we will use the net proceeds from this offering for our operations and for other general corporate purposes, including, but not limited to, our internal research and development programs and the development of new programs, general working capital and possible future acquisitions.

These expected uses of the net proceeds from this offering represent our intentions based upon our current financial condition, results of operations, business plans and conditions. As of the date of this prospectus, we cannot predict with certainty all of the particular uses for the net proceeds to be received upon the closing of this offering or the amounts that we will actually spend on the uses set forth above. The amounts and timing of our actual expenditures may vary significantly depending on numerous factors. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering.

Pending our use of the net proceeds from this offering as described above, we intend to invest the net proceeds in a variety of capital preservation investments, including short-term, investment grade, interest bearing instruments and U.S. government securities.

S- 4

PRICE RANGE OF OUR COMMON STOCK

Our shares of common stock have been listed and traded on The NASDAQ Capital Market under the symbol “RTTR” since June 24, 2015. Prior to that date, there was no public market for our common stock.

The following table sets forth, for the periods indicated, the high and low intra-day sale prices in dollars on The NASDAQ Capital Market for our common stock.

	2016
	High		Low
First Quarter	$	1.79	$	0.98
Second Quarter	$	1.89	$	1.10
Third Quarter	$	2.47	$	1.20
Fourth Quarter (through October 25, 2016)	$	3.26	$	1.45

		2015
		High		Low
Second Quarter (beginning June 24, 2015)	$	7.06	$	4.56
Third Quarter	$	5.48	$	1.90
Fourth Quarter	$	4.70	$	1.69

On October 24, 2016, the last reported sale price of our common stock on The NASDAQ Capital Market was $3.20 per share. As of October 24, 2016, there were approximately 42 stockholders of record of our common stock. These figures do not reflect the beneficial ownership or shares held in nominee name.

DIVIDEND POLICY

We have never declared or paid any cash dividends on our capital stock. We intend to retain future earnings, if any, to finance the operation and expansion of our business and do not anticipate paying any cash dividends in the foreseeable future. Any future determination related to dividend policy will be made at the discretion of our board of directors after considering our financial condition, results of operations, capital requirements, business prospects and other factors the board of directors deems relevant, and subject to the restrictions contained in any future financing instruments.

S- 5

CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of June 30, 2016, as follows:

	●	on an actual basis; and

	●	on an as adjusted basis to give further effect to the sale of 2,127,660 shares of common stock in this offering at a public offering price of $2.35 per share, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

You should read this table in conjunction with the information contained in this prospectus supplement and the accompanying prospectus and the information incorporated by reference from our quarterly reports on Form 10-Q for the three months ended March 31, 2016 and for the six months ended June 30, 2016, and the 2015 Form 10-K, including the historical financial statements and related notes included in each of those reports.

	As of June 30, 2016
	Actual			As Adjusted
	(unaudited)
Cash and cash equivalents	$	10,771,639		$	15,171,640
Long-term debt and capital lease obligations (including current portion)		—			—
Stockholders’ Equity:		8,126,517			12,526,518

Preferred stock, $0.001 par value; 5,000,000 shares authorized; 0 shares issued and outstanding as of June 30, 2016 and December 31, 2015.		—			—

Common Stock, $0.001 par value; 25,000,000 shares authorized; 8,584,661 and 8,582,004 shares issued and outstanding as of June 30, 2016 and December 31, 2015, respectively.		8,585			10,713

Additional paid-in capital		42,468,796			46,866,669
Accumulated deficit		(34,350,864	)		(34,350,864	)
Total shareholders’ equity		8,126,517			12,526,518
Total capitalization	$	10,874,042		$	15,274,043

S- 6

DILUTION

If you invest in our common stock in this offering, your ownership interest will be immediately diluted to the extent of the difference between the public offering price per share of our common stock and the as adjusted net tangible book value per share of our common stock immediately after this offering.

As of June 30, 2016, our historical net tangible book value was $8.1 million, or $0.95 per share of common stock. Our historical net tangible book value per share represents the amount of our total tangible assets less total liabilities divided by the number of shares of common stock outstanding as of June 30, 2016.

Our as adjusted net tangible book value as of June 30, 2016 would have been $12.5 million or $1.17 per share of common stock, after giving effect to the sale of the 2,127,660 shares of common stock in this offering at an offering price of $2.35 per share, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us. This amount represents an immediate increase in adjusted net tangible book value of $0.22 per share to our existing stockholders, and an immediate dilution in adjusted net tangible book value of approximately $1.18 per share to new investors purchasing shares of common stock in this offering.

Dilution in net tangible book value per share represents the difference between the amount per share of our common stock paid by purchasers in this offering and the net tangible book value per share of our common stock immediately after this offering. The following table illustrates this dilution:

Offering price per share			$	2.35
Historical net tangible book value per share as of June 30, 2016	$	0.95
Increase in net tangible book value per share attributable to new investors	$	0.22

As adjusted net tangible book value per share after this offering			$	1.17

Dilution per share to new investors			$	1.18

If the underwriters exercise their option to purchase additional shares in full, the as adjusted net tangible book value will increase to $1.19 per share, representing an immediate dilution of $1.16 per share to new investors.

The number of shares of common stock to be outstanding after this offering excludes:

	●	578,321 shares of common stock issuable upon exercise of outstanding warrants at a weighted average exercise price of $8.45 per share;

	●	2,455,924 shares of common stock issuable upon exercise of outstanding options as of October 25, 2016, at a weighted average exercise price of $6.04 per share, of which 1,478,180 shares are vested as of such date, which includes 280,088 shares of common stock issuable upon exercise of options granted on October 25, 2016, consisting of 140,044 options to each of Andrew J. Ritter, our Founder and President, and Ira E. Ritter, our Executive Chairman and Chief Strategic Officer; and

	●	109,360 shares of common stock reserved for future issuance under the 2015 Plan.

S- 7

UNDERWRITING

Aegis Capital Corp. is acting as the representative of the underwriters and the sole book-running manager in this offering. We have entered into an underwriting agreement dated October 26, 2016 with the representative. Subject to the terms and conditions of the underwriting agreement, we have agreed to sell to each underwriter named below and each underwriter named below has severally and not jointly agreed to purchase from us, at the public offering price per share less the underwriting discounts and commissions set forth on the cover page of this prospectus, the number of shares of common stock listed next to its name in the following table:

Underwriters	Number of Shares
Aegis Capital Corp.		2,127,660

Total		2,127,660

The underwriters are committed to purchase all the shares of common stock offered by us other than those covered by the option to purchase additional shares described below, if they purchase any shares. The obligations of the underwriters may be terminated upon the occurrence of certain events specified in the underwriting agreement. Furthermore, pursuant to the underwriting agreement, the underwriters’ obligations are subject to customary conditions, representations and warranties contained in the underwriting agreement, such as receipt by the underwriters of officers’ certificates and legal opinions.

We have agreed to indemnify the underwriters against specified liabilities, including liabilities under the Securities Act of 1933, as amended, and to contribute to payments the underwriters may be required to make in respect thereof.

The underwriters are offering the shares, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel and other conditions specified in the underwriting agreement. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

Over-allotment Option. We have granted the underwriters an over-allotment option. This option, which is exercisable for up to 30 days after the date of this prospectus, permits the underwriters to purchase a maximum of 212,766 additional shares ( 10% of the shares sold in this offering) from us to cover over-allotments, if any. If the underwriters exercise all or part of this option, they will purchase shares covered by the option at the public offering price per share, less the underwriting discounts and commissions. If this option is exercised in full, the total offering price to the public will be $5,500,001 and the total net proceeds, before expenses, to us will be $5,115,001 .

Discounts and Commissions. The following table shows the public offering price, underwriting discount and proceeds, before expenses, to us. The information assumes either no exercise or full exercise by the underwriters of their over-allotment option.

	Per Share		Total Without Over-allotment Option		Total With Over-allotment Option
Public offering price	$	2.35	$	5,000,001	$	5,500,001
Underwriting discounts and commissions (7%)	$	0.1645	$	350,000	$	385,000
Proceeds, before expenses, to us	$	2.1855	$	4,650,001	$	5,115,001

The underwriters propose to offer the shares offered by us to the public at the public offering price per share set forth on the cover of this prospectus supplement. If all of the shares offered by us are not sold at the public offering price per share, the underwriters may change the offering price per share and other selling terms by means of a supplement to this prospectus.

We have agreed to pay the underwriters’ expenses relating to the offering, including (a) all filing fees and communication expenses relating to the registration of the shares to be sold in the offering with the SEC; (b) all filing fees associated with the review of the offering by FINRA; (c) all fees and expenses relating to the listing of such shares on The Nasdaq Capital Market; (d) all fees, expenses and disbursements relating to the registration, qualification or exemption of the shares under the securities laws of such foreign jurisdictions as the representative may reasonably designate; (e) the costs of all mailing and printing of the underwriting documents (including, without limitation, the underwriting agreement, any blue sky surveys and, if appropriate, any agreement among underwriters, selected dealers’ agreement, underwriters’ questionnaire and power of attorney), registration statements, prospectuses and all amendments, supplements and exhibits thereto and as many preliminary and final prospectuses as the representative may reasonably deem necessary; (f) the costs and expenses of a public relations firm; (g) the costs of preparing, printing and delivering certificates representing the shares; (h) fees and expenses of the transfer agent for the common stock; (i) stock transfer and/or stamp taxes, if any, payable upon the transfer of securities from us to representative; (j) the fees and expenses of our accountants; (k) the fees and expenses of our legal counsel and other agents and representatives; (l) the fees and expenses of the underwriters’ legal counsel not to exceed $50,000; and (m) the $10,000 cost associated with the underwriter’s use of Ipreo’s book-building, prospectus tracking and compliance software for the offering; provided, however, that we will not be obligated to pay more than an aggregate of $5,000 in any expenses in connection with clause (d) above.

S- 8

We estimate that the total expenses of the offering payable by us, excluding the total underwriting discounts and commissions, will be approximately $250,000 .

Lock-Up Agreements. We and our directors and officers have entered into lock up agreements with the representative pursuant to which each of these persons or entities, for a period of (i) 75 days (in the case of our directors and officers) and (ii) 45 days (in the case of the Company and any successor to the Company) from the date of the underwriting agreement without the prior written consent of the representative, have agreed not to (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of our securities or any securities convertible into or exercisable or exchangeable for shares of our common stock; (2) file or caused to be filed any registration statement relating to the offering of any shares of our capital stock or any securities convertible into or exercisable or exchangeable for shares of our capital stock; or (3) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of our capital stock, whether any such transaction described in clause (1), (2) or (3) above is to be settled by delivery of shares of our capital stock or such other securities, in cash or otherwise, except for certain exceptions and limitations.

Electronic Offer, Sale and Distribution of Securities. A prospectus supplement in electronic format may be made available on the websites maintained by one or more of the underwriters or selling group members, if any, participating in this offering and one or more of the underwriters participating in this offering may distribute prospectus supplements electronically. The representative may agree to allocate a number of shares and warrants to underwriters and selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by the underwriters and selling group members that will make internet distributions on the same basis as other allocations. Other than the prospectus supplement in electronic format, the information on these websites is not part of, nor incorporated by reference into, this prospectus supplement or the registration statement of which this prospectus supplement forms a part, has not been approved or endorsed by us or any underwriter in its capacity as underwriter, and should not be relied upon by investors.

NASDAQ Capital Market Listing. Our common stock is listed on The NASDAQ Capital Market under the symbol “RTTR.”

Stabilization. In connection with this offering, the underwriters may engage in stabilizing transactions, over-allotment transactions, syndicate-covering transactions, penalty bids and purchases to cover positions created by short sales.

	●	Stabilizing transactions permit bids to purchase shares so long as the stabilizing bids do not exceed a specified maximum, and are engaged in for the purpose of preventing or retarding a decline in the market price of the shares while the offering is in progress.

	●	Over-allotment transactions involve sales by the underwriters of shares in excess of the number of shares the underwriters are obligated to purchase. This creates a syndicate short position that may be either a covered short position or a naked short position. In a covered short position, the number of shares over-allotted by the underwriters is not greater than the number of shares that they may purchase in the over-allotment option. In a naked short position, the number of shares involved is greater than the number of shares in the over-allotment option. The underwriters may close out any short position by exercising their over-allotment option and/or purchasing shares in the open market.

	●	Syndicate covering transactions involve purchases of shares in the open market after the distribution has been completed in order to cover syndicate short positions. In determining the source of shares to close out the short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared with the price at which they may purchase shares through exercise of the over-allotment option. If the underwriters sell more shares than could be covered by exercise of the over-allotment option and, therefore, have a naked short position, the position can be closed out only by buying shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that after pricing there could be downward pressure on the price of the shares in the open market that could adversely affect investors who purchase in the offering.

	●	Penalty bids permit the representative to reclaim a selling concession from a syndicate member when the shares originally sold by that syndicate member are purchased in stabilizing or syndicate covering transactions to cover syndicate short positions.

S- 9

These stabilizing transactions, syndicate covering transactions and penalty bids may have the effect of raising or maintaining the market price of our shares of common stock or preventing or retarding a decline in the market price of our shares of common stock. As a result, the price of our common stock in the open market may be higher than it would otherwise be in the absence of these transactions. Neither we nor the underwriters make any representation or prediction as to the effect that the transactions described above may have on the price of our common stock. These transactions may be effected on The NASDAQ Capital Market, in the over-the-counter market or otherwise and, if commenced, may be discontinued at any time.

Passive market making. In connection with this offering, underwriters and selling group members may engage in passive market making transactions in our common stock on The NASDAQ Capital Market in accordance with Rule 103 of Regulation M under the Exchange Act, during a period before the commencement of offers or sales of the shares and extending through the completion of the distribution. A passive market maker must display its bid at a price not in excess of the highest independent bid of that security. However, if all independent bids are lowered below the passive market maker’s bid, then that bid must then be lowered when specified purchase limits are exceeded.

Certain Relationships

The underwriters and their affiliates have provided, or may in the future provide, various investment banking, commercial banking, financial advisory, brokerage and other services to us and our affiliates for which services they have received, and may in the future receive, customary fees and expense reimbursement. The representative of this offering was also the representative of our initial public offering.

Offer Restrictions Outside the United States

Other than in the United States, no action has been taken by us or the underwriters that would permit a public offering of the securities offered by this prospectus in any jurisdiction where action for that purpose is required. The securities offered by this prospectus may not be offered or sold, directly or indirectly, nor may this prospectus or any other offering material or advertisements in connection with the offer and sale of any such securities be distributed or published in any jurisdiction, except under circumstances that will result in compliance with the applicable rules and regulations of that jurisdiction. Persons into whose possession this prospectus comes are advised to inform themselves about and to observe any restrictions relating to the offering and the distribution of this prospectus. This prospectus does not constitute an offer to sell or a solicitation of an offer to buy any securities offered by this prospectus in any jurisdiction in which such an offer or a solicitation is unlawful.

S- 10

LEGAL MATTERS

The validity of the securities being offered by this prospectus will be passed upon for us by Reed Smith LLP, Los Angeles, California. Certain legal matters in connection with this offering will be passed upon for the underwriters by Greenberg Traurig, LLP, New York, New York.

EXPERTS

Mayer Hoffman McCann P.C., our independent registered public accounting firm, has audited our balance sheets as of December 31, 2015 and 2014, and the related statements of operations, changes in securities subject to redemption and shareholders’ deficit and cash flows for each of the two years in the period ended December 31, 2015, as set forth in their report, which report expresses an unqualified opinion and includes an explanatory paragraph relating to our ability to continue as a going concern. We have incorporated by reference our financial statements in this prospectus supplement and in the accompanying registration statement in reliance on the report of Mayer Hoffman McCann P.C. given on their authority as experts in accounting and auditing, which report is also incorporated herein by reference.

S- 11

PROSPECTUS

RITTER PHARMACEUTICALS, INC.

$150,000,000

COMMON STOCK

PREFERRED STOCK

DEBT SECURITIES

WARRANTS

RIGHTS

PURCHASE CONTRACTS

UNITS

This prospectus will allow us to issue, from time to time at prices and on terms to be determined at or prior to the time of the offering, up to $150,000,000 of any combination of the securities described in this prospectus, either individually or in units. We may also offer common stock or preferred stock upon conversion of or exchange for the debt securities; common stock or preferred stock or debt securities upon the exercise of warrants, rights or performance of purchase contracts; or any combination of these securities upon the performance of purchase contracts.

This prospectus describes the general terms of these securities and the general manner in which these securities will be offered. We will provide you with the specific terms of any offering in one or more supplements to this prospectus. The prospectus supplements will also describe the specific manner in which these securities will be offered and may also supplement, update or amend information contained in this document. You should read this prospectus and any prospectus supplement, as well as any documents incorporated by reference into this prospectus or any prospectus supplement, carefully before you invest.

Our securities may be sold directly by us to you, through agents designated from time to time or to or through underwriters or dealers. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus and in the applicable prospectus supplement. If any underwriters or agents are involved in the sale of our securities with respect to which this prospectus is being delivered, the names of such underwriters or agents and any applicable fees, commissions or discounts and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds that we expect to receive from such sale will also be set forth in a prospectus supplement.

Our common stock is listed on the NASDAQ Capital Market, under the symbol “RTTR.” On August 5, 2016, the last reported sale price of our common stock on the NASDAQ Capital Market was $1.31 per share.

As of August 5, 2016, the aggregate market value of our outstanding common stock held by non-affiliates was approximately $6.9 million, based on 8,584,661 shares of outstanding common stock, of which 5,267,606 shares were held by non-affiliates, and a per share price of $1.31 based on the closing sale price of our common stock as of August 5, 2016. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities pursuant to this prospectus with a value of more than one-third of the aggregate market value of our common stock held by non-affiliates in any twelve-month period, so long as the aggregate market value of our common stock held by non-affiliates is less than $75,000,000. In the event that subsequent to the date of this prospectus, the aggregate market value of our outstanding common stock held by non-affiliates equals or exceeds $75,000,000, then the one-third limitation on sales shall not apply to additional sales made pursuant to this prospectus. We have not offered any securities pursuant to General Instruction I.B.6 of Form S-3 during the twelve calendar months prior to and including the date of this prospectus.

Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should consider carefully the risks that we have described on page 2 of this prospectus under the caption “Risk Factors.” We may include specific risk factors in supplements to this prospectus under the caption “Risk Factors.” This prospectus may not be used to sell our securities unless accompanied by a prospectus supplement.

The date of this prospectus is August 23, 2016

TABLE OF CONTENTS

	Page

ABOUT THIS PROSPECTUS	ii

PROSPECTUS SUMMARY	1

RISK FACTORS	2

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	3

RATIO OF EARNINGS TO FIXED CHARGES	4

USE OF PROCEEDS	4

PLAN OF DISTRIBUTION	6

DESCRIPTION OF CAPITAL STOCK	8

DESCRIPTION OF DEBT SECURITIES	11

DESCRIPTION OF WARRANTS	13

DESCRIPTION OF RIGHTS	14

DESCRIPTION OF PURCHASE CONTRACTS	15

DESCRIPTION OF UNITS	16

LEGAL MATTERS	17

EXPERTS	17

WHERE YOU CAN FIND MORE INFORMATION	17

INCORPORATION OF INFORMATION BY REFERENCE	18

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may offer shares of our common stock, preferred stock, various series of debt securities and/or warrants, rights or purchase contracts to purchase any of such securities, either individually or in units, in one or more offerings, with a total value of up to $150,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering.

This prospectus does not contain all of the information included in the registration statement. For a more complete understanding of the offering of the securities, you should refer to the registration statement, including its exhibits. The prospectus supplement may also add, update or change information contained or incorporated by reference in this prospectus. However, no prospectus supplement will offer a security that is not registered and described in this prospectus at the time of its effectiveness. This prospectus, together with the applicable prospectus supplements and the documents incorporated by reference into this prospectus, includes all material information relating to the offering of securities under this prospectus. You should carefully read this prospectus, the applicable prospectus supplement, the information and documents incorporated herein by reference and the additional information under the heading “Where You Can Find More Information” before making an investment decision.

You should rely only on the information we have provided or incorporated by reference in this prospectus or any prospectus supplement. We have not authorized anyone to provide you with information different from that contained or incorporated by reference in this prospectus. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained or incorporated by reference in this prospectus. You must not rely on any unauthorized information or representation. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus or any prospectus supplement is accurate only as of the date on the front of the document and that any information we have incorporated herein by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of a security.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference in the accompanying prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

This prospectus may not be used to consummate sales of our securities, unless it is accompanied by a prospectus supplement. To the extent there are inconsistencies between any prospectus supplement, this prospectus and any documents incorporated by reference, the document with the most recent date will control.

We were formed as a Nevada limited liability company on March 29, 2004 under the name Ritter Natural Sciences, LLC. On September 16, 2008, we converted into a Delaware corporation under the name Ritter Pharmaceuticals, Inc. Unless the context otherwise requires, “Ritter,” “the Company,” “we,” “us,” “our” and similar terms refer to Ritter Pharmaceuticals, Inc.

PROSPECTUS SUMMARY

The following is a summary of what we believe to be the most important aspects of our business and the offering of our securities under this prospectus. We urge you to read this entire prospectus, including the more detailed consolidated financial statements, notes to the consolidated financial statements and other information incorporated by reference from our other filings with the SEC or included in any applicable prospectus supplement. Investing in our securities involves risks. Therefore, carefully consider the risk factors set forth in any prospectus supplements and in our most recent annual and quarterly filings with the SEC, as well as other information in this prospectus and any prospectus supplements and the documents incorporated by reference herein or therein, before purchasing our securities. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities.

The Company

Corporate Information

We were formed as a Nevada limited liability company on March 29, 2004 under the name Ritter Natural Sciences, LLC. On September 16, 2008, we converted into a Delaware corporation under the name Ritter Pharmaceuticals, Inc. Our principal executive offices are located at 1880 Century Park East, #1000, Los Angeles, CA 90067, and our telephone number is (310) 203-1000. Our website address is www.ritterpharmaceuticals.com . The information contained on, or that can be accessed through, our website is not part of this prospectus.

Offerings Under This Prospectus

Under this prospectus, we may offer shares of our common stock, preferred stock, various series of debt securities and/or warrants, rights or purchase contracts to purchase any of such securities, either individually or in units, with a total value of up to $150,000,000, from time to time at prices and on terms to be determined by market conditions at the time of the offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities.

The prospectus supplement also may add, update or change information contained in this prospectus or in documents we have incorporated by reference into this prospectus. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents or underwriters, reserve the right to accept or reject all or part of any proposed purchase of securities. If we offer securities through agents or underwriters, we will include in the applicable prospectus supplement:

	●	the names of those agents or underwriters;

	●	applicable fees, discounts and commissions to be paid to them;

	●	details regarding over-allotment options, if any; and

	●	the net proceeds to us.

RISK FACTORS

Please carefully consider the risk factors described in our periodic reports filed with the SEC, which are incorporated by reference in this prospectus. Before making an investment decision, you should carefully consider these risks as well as other information we include or incorporate by reference in this prospectus or include in any applicable prospectus supplement. Additional risks and uncertainties not presently known to us or that we deem currently immaterial may also impair our business operations or adversely affect our results of operations or financial condition.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

Some of the statements in this prospectus and in any prospectus supplement we may file constitute “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934 as amended (the “Exchange Act”). These statements relate to future events concerning our business and to our future revenues, operating results and financial condition. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “forecast,” “predict,” “propose,” “potential” or “continue,” or the negative of those terms or other comparable terminology.

Any forward looking statements contained in this prospectus or any prospectus supplement are only estimates or predictions of future events based on information currently available to our management and management’s current beliefs about the potential outcome of future events. Whether these future events will occur as management anticipates, whether we will achieve our business objectives, and whether our revenues, operating results or financial condition will improve in future periods are subject to numerous risks. There are a number of important factors that could cause actual results to differ materially from the results anticipated by these forward-looking statements. These important factors include those that we discuss under the heading “Risk Factors” and in other sections of our Annual Report on Form 10-K for the year ended December 31, 2015, our Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2016 and June 30, 2016, all filed with the SEC, as well as in our Current Reports filed on Form 8-K from time to time with the SEC, that are incorporated by reference into this prospectus. You should read these factors and the other cautionary statements made in this prospectus and in the documents we incorporate by reference into this prospectus as being applicable to all related forward-looking statements wherever they appear in this prospectus or the documents we incorporate by reference into this prospectus. If one or more of these factors materialize, or if any underlying assumptions prove incorrect, our actual results, performance or achievements may vary materially from any future results, performance or achievements expressed or implied by these forward-looking statements. We undertake no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

RATIO OF EARNINGS TO FIXED CHARGES

Any time debt securities are offered pursuant to this prospectus, we will provide a table setting forth our ratio of earnings to fixed charges on a historical basis in the applicable prospectus supplement, if required.

Year Ended December 31,

Six Months Ended

2012

2013

2014

2015

June 30, 2016

Ratio of earnings to fixed charges

(*) We did not record earnings for any of the years ended December 31, 2012, 2013, 2014 or 2015 or the six months ended June 30, 2016. Accordingly, our earnings were insufficient to cover fixed charges for such periods and we are unable to disclose a ratio of earnings to fixed charges for such periods. The dollar amount of the deficiency in earnings available for fixed charges for the years ended December 31, 2012, 2013, 2014 and 2015 and the six months ended June 30, 2016 was $3,425,840, $2,095,831, $2,473,465, $8,787,771 and $7,267,922, respectively.

USE OF PROCEEDS

We cannot assure you that we will receive any proceeds in connection with securities which may be offered pursuant to this prospectus. Unless otherwise indicated in the applicable prospectus supplement, we intend to use any net proceeds from the sale of securities under this prospectus for our operations and for other general corporate purposes, including, but not limited to, our internal research and development programs and the development of new programs, general working capital and possible future acquisitions. We have not determined the amounts we plan to spend on any of the areas listed above or the timing of these expenditures. As a result, our management will have broad discretion to allocate the net proceeds, if any, we receive in connection with securities offered pursuant to this prospectus for any purpose. Pending application of the net proceeds as described above, we may initially invest the net proceeds in short-term, investment-grade, interest-bearing securities or apply them to the reduction of short-term indebtedness.

PLAN OF DISTRIBUTION

General Plan of Distribution

We may offer securities under this prospectus from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities (1) through underwriters or dealers, (2) through agents or (3) directly to one or more purchasers, or through a combination of such methods. We may distribute the securities from time to time in one or more transactions at:

	●	a fixed price or prices, which may be changed from time to time;

	●	market prices prevailing at the time of sale;

	●	prices related to the prevailing market prices; or

	●	negotiated prices.

We may directly solicit offers to purchase the securities being offered by this prospectus. We may also designate agents to solicit offers to purchase the securities from time to time. We will name in a prospectus supplement any underwriter or agent involved in the offer or sale of the securities.

If we utilize a dealer in the sale of the securities being offered by this prospectus, we will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

If we utilize an underwriter in the sale of the securities being offered by this prospectus, we will execute an underwriting agreement with the underwriter at the time of sale, and we will provide the name of any underwriter in the prospectus supplement which the underwriter will use to make re-sales of the securities to the public. In connection with the sale of the securities, we, or the purchasers of the securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell the securities to or through dealers, and the underwriter may compensate those dealers in the form of discounts, concessions or commissions.

With respect to underwritten public offerings, negotiated transactions and block trades, we will provide in the applicable prospectus supplement information regarding any compensation we pay to underwriters, dealers or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers. Underwriters, dealers and agents participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended, or the Securities Act, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. We may enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, or to contribute to payments they may be required to make in respect thereof.

If so indicated in the applicable prospectus supplement, we will authorize underwriters or other persons acting as our agents to solicit offers by certain institutions to purchase securities from us pursuant to delayed delivery contracts providing for payment and delivery on the date stated in the prospectus supplement. Each contract will be for an amount not less than, and the aggregate amount of securities sold pursuant to such contracts shall not be less nor more than, the respective amounts stated in the prospectus supplement. Institutions with whom the contracts, when authorized, may be made include commercial and savings banks, insurance companies, pension funds, investment companies, educational and charitable institutions and other institutions, but shall in all cases be subject to our approval. Delayed delivery contracts will not be subject to any conditions except that:

	●	the purchase by an institution of the securities covered under that contract shall not at the time of delivery be prohibited under the laws of the jurisdiction to which that institution is subject; and

	●	if the securities are also being sold to underwriters acting as principals for their own account, the underwriters shall have purchased such securities not sold for delayed delivery. The underwriters and other persons acting as our agents will not have any responsibility in respect of the validity or performance of delayed delivery contracts.

Shares of our common stock sold pursuant to the registration statement of which this prospectus is a part will be authorized for quotation and trading on the NASDAQ Capital Market. The applicable prospectus supplement will contain information, where applicable, as to any other listing, if any, on the NASDAQ Capital Market or any securities market or other securities exchange of the securities covered by the prospectus supplement. We can make no assurance as to the liquidity of or the existence of trading markets for any of the securities.

In order to facilitate the offering of the securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than we sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing the applicable security in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if the securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc., or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

The underwriters, dealers and agents may engage in other transactions with us, or perform other services for us, in the ordinary course of their business.

DESCRIPTION OF CAPITAL STOCK

General

Our authorized capital stock consists of 30,000,000 shares, all with a par value of $0.001 per share, 25,000,000 of which are designated as common stock and 5,000,000 of which are designated as preferred stock.

The following description of our capital stock and certain provisions of our amended and restated certificate of incorporation and amended and restated bylaws are summaries and are qualified by reference to our amended and restated certificate of incorporation and our amended and restated bylaws.

All share numbers have been adjusted to reflect the 1-for-7.15 reverse stock split of our common stock. Preferred share issuances referred to below are as of their date of issuance. The preferred stock described below converted into shares of our common stock on a 7.15-for-1 basis prior to the closing of our initial public offering.

As of August 5, 2016, we had 8,584,661 shares of our common stock outstanding and zero shares of preferred stock outstanding. As of August 5, 2016, we also had outstanding options to acquire 2,193,877 shares of our common stock, having a weighted-average exercise price of $6.44 per share, and warrants to purchase an aggregate of 578,321 shares of our common stock.

Common Stock

Pursuant to the terms of our amended and restated certificate of incorporation, the holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders, except on matters relating solely to terms of preferred stock. Subject to preferences that may be applicable to any outstanding preferred stock, the holders of common stock will be entitled to receive ratably such dividends, if any, as may be declared from time to time by the board of directors out of funds legally available therefor. See “Dividend Policy.” In the event of our liquidation, dissolution or winding up, the holders of our common stock will be entitled to share ratably in all assets remaining after payment of liabilities, subject to prior distribution rights of preferred stock, if any, then outstanding. The holders of our common stock will have no preemptive or conversion rights or other subscription rights. There will be no redemption or sinking fund provisions applicable to our common stock.

Warrants

In December 2014, we issued an aggregate of 2,369,228 shares of Series C preferred stock and warrants, or the 2014 Warrants, to purchase a like number of shares of our common stock, for aggregate gross proceeds of $3,081,893. All of the shares of Series C preferred stock were converted into 331,358 shares of our common stock prior to the closing of the initial public offering. Each 2014 Warrant has a term of seven years and provides for the holder to purchase each share of our common stock covered thereby at a purchase price of $9.30 per share of common stock.

In connection with the Series C Financing, all of the 2014 Notes were converted into shares of Series C preferred stock. A total of $535,000 unpaid principal plus accrued interest of $18,342 on the convertible notes converted into 567,529 shares of Series C preferred stock, which were later converted into 79,374 shares of our common stock prior to the closing of our initial public offering, and 79,374 2014 Warrants. A total of $70,000 unpaid principal plus accrued interest of $537 on a note payable was extinguished and converted into 54,259 shares of Series C preferred stock, which were later converted into 7,589 shares of our common stock prior to the closing of our initial public offering and 7,589 2014 Warrants.

Warrants to Representative in Initial Public Offering

In connection with our initial public offering, we issued to the representative of the underwriters warrants to purchase up to a total of 160,000 shares of common stock. The warrants are exercisable at any time, and from time to time, in whole or in part, during the four-year period commencing one year from the effective date of our initial public offering, and ending on the date that is five years from the effective date of the offering in compliance with FINRA Rule 5110(f)(2)(G)(i). The warrants are exercisable at a per share price equal to $6.25 per share. The warrants provide for registration rights upon request, in certain cases. The demand registration right provided will not be greater than five years from the effective date of the offering in compliance with FINRA Rule 5110(f)(2)(G)(iv). The piggyback registration right provided will not be greater than seven years from the effective date of the offering in compliance with FINRA Rule 5110(f)(2)(G)(v). We will bear all fees and expenses attendant to registering the securities issuable on exercise of the warrants other than underwriting commissions incurred and payable by the holders. The exercise price and number of shares issuable upon exercise of the warrants may be adjusted in certain circumstances including in the event of a stock dividend or our recapitalization, reorganization, merger or consolidation. However, the warrant exercise price or underlying shares will not be adjusted for issuances of shares of common stock at a price below the warrant exercise price.

Preferred Stock

Pursuant to the terms of our amended and restated certificate of incorporation, our board of directors has the authority to issue preferred stock in one or more classes or series and to fix the designations, powers, preferences and rights, and the qualifications, limitations or restrictions thereof, including dividend rights, conversion right, voting rights, terms of redemption, liquidation preferences and the number of shares constituting any class or series, without further vote or action by the stockholders. Although we have no present plans to issue any shares of preferred stock, the issuance of shares of preferred stock, or the issuance of rights to purchase such shares, could decrease the amount of earnings and assets available for distribution to the holders of common stock, could adversely affect the rights and powers, including voting rights, of the common stock, and could have the effect of delaying, deterring or preventing a change of control of us or an unsolicited acquisition proposal.

Registration Rights

On September 15, 2008, we entered into an Investors’ Rights Agreement with certain holders of our preferred stock. Such Investors’ Rights Agreement was amended and restated on November 17, 2010. The Amended and Restated Investors’ Rights Agreement was amended on each of January 13, 2011, February 6, 2012, December 4, 2014 and June 9, 2015. The Amended and Restated Investors’ Rights Agreement, as amended, provides such holders with certain demand and piggyback registration rights with respect to shares of our common stock into which the shares of our preferred stock are convertible.

Aspire Capital Registration Rights

On December 18, 2015, we entered into a Registration Rights Agreement with Aspire Capital Fund, LLC (“Aspire Capital”), in which we agreed to file one or more registration statements as permissible and necessary to register under the Securities Act, the sale of the shares of our common stock that have been and may be issued to Aspire Capital under the common stock purchase agreement, dated December 18, 2015, by and between us and Aspire Capital (the “Purchase Agreement”). A registration statement (No. 333-208818) registering the sale of shares of our common stock that have been and may be issued to Aspire Capital under the Purchase Agreement was declared effective by the SEC on February 11, 2016.

Anti-Takeover Effects of Delaware Law and Our Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws

The provisions of Delaware law and our amended and restated certificate of incorporation and amended and restated bylaws, could discourage or make it more difficult to accomplish a proxy contest or other change in our management or the acquisition of control by a holder of a substantial amount of our voting stock. It is possible that these provisions could make it more difficult to accomplish, or could deter, transactions that stockholders may otherwise consider to be in their best interests or in our best interests. These provisions are intended to enhance the likelihood of continuity and stability in the composition of our board of directors and in the policies formulated by the board of directors and to discourage certain types of transactions that may involve an actual or threatened change of our control. These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal and to discourage certain tactics that may be used in proxy fights. Such provisions also may have the effect of preventing changes in our management.

Delaware Statutory Business Combinations Provision . We are subject to the anti-takeover provisions of Section 203 of the Delaware General Corporation Law, or the DGCL. Section 203 prohibits a publicly-held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless the business combination is, or the transaction in which the person became an interested stockholder was, approved in a prescribed manner or another prescribed exception applies. For purposes of Section 203, a “business combination” is defined broadly to include a merger, asset sale or other transaction resulting in a financial benefit to the interested stockholder, and, subject to certain exceptions, an “interested stockholder” is a person who, together with his or her affiliates and associates, owns, or within three years prior, did own, 15% or more of the corporation’s voting stock.

Election and Removal of Directors . Except as may otherwise be provided by the DGCL, any director or the entire board of directors may be removed, with or without cause, at an annual meeting or a special meeting called for that purpose, by the affirmative vote of the majority of the votes cast by the shares of our capital stock present in person or represented by proxy at such meeting and entitled to vote thereon, provided a quorum is present. Vacancies on our board of directors resulting from the removal of directors and newly created directorships resulting from any increase in the number of directors may be filled solely by the affirmative vote of a majority of the remaining directors then in office (although less than a quorum) or by the sole remaining director. This system of electing and removing directors may discourage a third party from making a tender offer or otherwise attempting to obtain control of us, because it generally makes it more difficult for stockholders to replace a majority of our directors. Our amended and restated certificate of incorporation and amended and restated bylaws do not provide for cumulative voting in the election of directors.

Advance Notice Provisions for Stockholder Proposals and Stockholder Nominations of Directors . Our amended and restated bylaws provide that, for nominations to the board of directors or for other business to be properly brought by a stockholder before a meeting of stockholders, the stockholder must first have given timely notice of the proposal in writing to our Secretary. For an annual meeting, a stockholder’s notice generally must be delivered not less than 90 days or more than 120 days prior to the anniversary of the previous year’s annual meeting.

Special Meetings of Stockholders . Special meetings of the stockholders may be called at any time only by the board of directors, the Chairman of the board of directors, the Chief Executive Officer or the President, subject to the rights of the holders of any series of preferred stock then outstanding.

Blank-Check Preferred Stock . Our board of directors is authorized to issue, without stockholder approval, preferred stock, the rights of which will be determined at the discretion of the board of directors and that, if issued, could operate as a “poison pill” to dilute the stock ownership of a potential hostile acquirer to prevent an acquisition that our board of directors does not approve.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Corporate Stock Transfer, Inc.

Stock Market Listing

Our common stock is listed on The NASDAQ Capital Market under the symbol “RTTR.”

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of the debt securities that we may offer under this prospectus. While the terms we have summarized below will apply generally to any future debt securities we may offer pursuant to this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. If we so indicate in a prospectus supplement, the terms of any debt securities offered under such prospectus supplement may differ from the terms we describe below, and to the extent the terms set forth in a prospectus supplement differ from the terms described below, the terms set forth in the prospectus supplement shall control.

We may sell from time to time, in one or more offerings under this prospectus, debt securities, which may be senior or subordinated. We will issue any such senior debt securities under a senior indenture that we will enter into with a trustee to be named in the senior indenture. We will issue any such subordinated debt securities under a subordinated indenture, which we will enter into with a trustee to be named in the subordinated indenture. We use the term “indentures” to refer to either the senior indenture or the subordinated indenture, as applicable. The indentures will be qualified under the Trust Indenture Act of 1939, as in effect on the date of the indenture. We use the term “debenture trustee” to refer to either the trustee under the senior indenture or the trustee under the subordinated indenture, as applicable.

The following summaries of material provisions of the senior debt securities, the subordinated debt securities and the indentures are subject to, and qualified in their entirety by reference to, all the provisions of the indenture applicable to a particular series of debt securities.

General

Each indenture will provide that debt securities may be issued from time to time in one or more series and may be denominated and payable in foreign currencies or units based on or relating to foreign currencies. Neither indenture will limit the amount of debt securities that may be issued thereunder, and each indenture will provide that the specific terms of any series of debt securities shall be set forth in, or determined pursuant to, an authorizing resolution and/or a supplemental indenture, if any, relating to such series.

We will describe in each prospectus supplement the following terms relating to a series of debt securities:

	●	the title or designation;

	●	the aggregate principal amount and any limit on the amount that may be issued;

	●	the currency or units based on or relating to currencies in which debt securities of such series are denominated and the currency or units in which principal or interest or both will or may be payable;

	●	whether we will issue the series of debt securities in global form, the terms of any global securities and who the depositary will be;

	●	the maturity date and the date or dates on which principal will be payable;

	●	the interest rate, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the date or dates interest will be payable and the record dates for interest payment dates or the method for determining such dates;

	●	whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

	●	the terms of the subordination of any series of subordinated debt;

	●	the place or places where payments will be payable;

	●	our right, if any, to defer payment of interest and the maximum length of any such deferral period;

	●	the date, if any, after which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional redemption provisions;

	●	the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities;

	●	whether the indenture will restrict our ability to pay dividends, or will require us to maintain any asset ratios or reserves;

	●	whether we will be restricted from incurring any additional indebtedness;

	●	a discussion on any material or special U.S. federal income tax considerations applicable to a series of debt securities;

	●	the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof; and

	●	any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities.

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on the federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

Conversion or Exchange Rights

We will set forth in the prospectus supplement the terms, if any, on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Information Concerning the Debenture Trustee

The debenture trustee, other than during the occurrence and continuance of an event of default under the applicable indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the debenture trustee under such indenture must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the debenture trustee is under no obligation to exercise any of the powers given it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check which we will mail to the holder. Unless we otherwise indicate in a prospectus supplement, we will designate the corporate trust office of the debenture trustee in the City of New York as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the debenture trustee for the payment of the principal of or any premium or interest on any debt securities which remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the security thereafter may look only to us for payment thereof.

Governing Law

The indentures and the debt securities will be governed by and construed in accordance with the laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

Subordination of Subordinated Debt Securities

Our obligations pursuant to any subordinated debt securities will be unsecured and will be subordinate and junior in priority of payment to certain of our other indebtedness to the extent described in a prospectus supplement. The subordinated indenture does not limit the amount of senior indebtedness we may incur. It also does not limit us from issuing any other secured or unsecured debt.

DESCRIPTION OF WARRANTS

General

We may issue warrants to our stockholders to purchase shares of our common stock, preferred stock and/or debt securities. We may offer warrants separately or together with one or more additional warrants, debt securities, common stock, preferred stock, rights or purchase contracts, or any combination of those securities in the form of units, as described in the applicable prospectus supplement. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent. The warrant agent will act solely as our agent in connection with the certificates relating to the rights of the series of certificates and will not assume any obligation or relationship of agency or trust for or with any holders of rights certificates or beneficial owners of rights. The following description sets forth certain general terms and provisions of the rights to which any prospectus supplement may relate. The particular terms of the warrant to which any prospectus supplement may relate and the extent, if any, to which the general provisions may apply to the rights so offered will be described in the applicable prospectus supplement. To the extent that any particular terms of the warrant, warrant agreement or warrant certificates described in a prospectus supplement differ from any of the terms described below, then the terms described below will be deemed to have been superseded by that prospectus supplement. We encourage you to read the applicable warrant agreement and warrant certificate for additional information before you decide whether to purchase any of our rights.

We will provide in a prospectus supplement the following terms of the warrants being issued:

	●	the specific designation and aggregate number of, and the price at which we will issue, the warrants;

	●	the currency or currency units in which the offering price, if any, and the exercise price are payable;

	●	the designation, amount and terms of the securities purchasable upon exercise of the warrants;

	●	if applicable, the exercise price for shares of our common stock and the number of shares of common stock to be received upon exercise of the warrants;

	●	if applicable, the exercise price for shares of our preferred stock, the number of shares of preferred stock to be received upon exercise, and a description of that series of our preferred stock;

	●	if applicable, the exercise price for our debt securities, the amount of debt securities to be received upon exercise, and a description of that series of debt securities;

	●	the date on which the right to exercise the warrants will begin and the date on which that right will expire or, if you may not continuously exercise the warrants throughout that period, the specific date or dates on which you may exercise the warrants;

	●	whether the warrants will be issued in fully registered form or bearer form, in definitive or global form or in any combination of these forms, although, in any case, the form of a warrant included in a unit will correspond to the form of the unit and of any security included in that unit;

	●	any applicable material U.S. federal income tax consequences;

	●	the identity of the warrant agent for the warrants and of any other depositaries, execution or paying agents, transfer agents, registrars or other agents;

	●	the proposed listing, if any, of the warrants or any securities purchasable upon exercise of the warrants on any securities exchange;

	●	if applicable, the date from and after which the warrants and the common stock, preferred stock and/or debt securities will be separately transferable;

	●	if applicable, the minimum or maximum amount of the warrants that may be exercised at any one time;

	●	information with respect to book-entry procedures, if any;

	●	the anti-dilution provisions of the warrants, if any;

	●	any redemption or call provisions;

	●	whether the warrants may be sold separately or with other securities as parts of units; and

	●	any additional terms of the warrants, including terms, procedures and limitations relating to the exchange and exercise of the warrants.

Each warrant will entitle the holder of rights to purchase for cash the principal amount of shares of common stock or other securities at the exercise price provided in the applicable prospectus supplement. Warrants may be exercised at any time up to the close of business on the expiration date for the rights provided in the applicable prospectus supplement.

Holders may exercise warrants as described in the applicable prospectus supplement. Upon receipt of payment and the warrant certificate properly completed and duly executed at the corporate trust office of the rights agent or any other office indicated in the prospectus supplement, we will, as soon as practicable, forward the shares of common stock or other securities, as applicable, purchasable upon exercise of the rights. If less than all of the warrants issued in any rights offering are exercised, we may offer any unsubscribed securities directly to persons other than stockholders, to or through agents, underwriters or dealers or through a combination of such methods, including pursuant to standby arrangements, as described in the applicable prospectus supplement.

Warrant Agent

The warrant agent for any warrants we offer will be set forth in the applicable prospectus supplement.

DESCRIPTION OF RIGHTS

General

We may issue rights to our stockholders to purchase shares of our common stock, preferred stock, and/or debt securities described in this prospectus. We may offer rights separately or together with one or more additional rights, debt securities, common stock, warrants or purchase contracts, or any combination of those securities in the form of units, as described in the applicable prospectus supplement. Each series of rights will be issued under a separate rights agreement to be entered into between us and a bank or trust company, as rights agent. The rights agent will act solely as our agent in connection with the certificates relating to the rights of the series of certificates and will not assume any obligation or relationship of agency or trust for or with any holders of rights certificates or beneficial owners of rights. The following description sets forth certain general terms and provisions of the rights to which any prospectus supplement may relate. The particular terms of the rights to which any prospectus supplement may relate and the extent, if any, to which the general provisions may apply to the rights so offered will be described in the applicable prospectus supplement. To the extent that any particular terms of the rights, rights agreement or rights certificates described in a prospectus supplement differ from any of the terms described below, then the terms described below will be deemed to have been superseded by that prospectus supplement. We encourage you to read the applicable rights agreement and rights certificate for additional information before you decide whether to purchase any of our rights.

We will provide in a prospectus supplement the following terms of the rights being issued:

	●	the date of determining the stockholders entitled to the rights distribution;

	●	the aggregate number of shares of common stock or other securities purchasable upon exercise of the rights;

	●	the exercise price;

	●	the aggregate number of rights issued;

	●	whether the rights are transferrable and the date, if any, on and after which the rights may be separately transferred;

	●	the date on which the right to exercise the rights will commence, and the date on which the right to exercise the rights will expire;

	●	the method by which holders of rights will be entitled to exercise;

	●	the conditions to the completion of the offering, if any;

	●	the withdrawal, termination and cancellation rights, if any;

	●	whether there are any backstop or standby purchaser or purchasers and the terms of their commitment, if any;

	●	whether stockholders are entitled to oversubscription rights, if any;

	●	any applicable U.S. federal income tax considerations; and

	●	any other terms of the rights, including terms, procedures and limitations relating to the distribution, exchange and exercise of the rights, as applicable.

Each right will entitle the holder of rights to purchase for cash the principal amount of shares of common stock or other securities at the exercise price provided in the applicable prospectus supplement. Rights may be exercised at any time up to the close of business on the expiration date for the rights provided in the applicable prospectus supplement.

Holders may exercise rights as described in the applicable prospectus supplement. Upon receipt of payment and the rights certificate properly completed and duly executed at the corporate trust office of the rights agent or any other office indicated in the prospectus supplement, we will, as soon as practicable, forward the shares of common stock or other securities, as applicable, purchasable upon exercise of the rights. If less than all of the rights issued in any rights offering are exercised, we may offer any unsubscribed securities directly to persons other than stockholders, to or through agents, underwriters or dealers or through a combination of such methods, including pursuant to standby arrangements, as described in the applicable prospectus supplement.

Rights Agent

The rights agent for any rights we offer will be set forth in the applicable prospectus supplement.

DESCRIPTION OF PURCHASE CONTRACTS

We may issue purchase contracts, including contracts obligating holders to purchase from us, and for us to sell to holders, a specific or variable number of our debt securities, shares of common stock, preferred stock, warrants or rights, or securities of an entity unaffiliated with us, or any combination of the above, as described in the applicable prospectus supplement. Alternatively, the purchase contracts may obligate us to purchase from holders, and obligate holders to sell to us, a specific or variable number of our debt securities, shares of common stock, warrants, rights or other property, or any combination of the above. The price of the securities or other property subject to the purchase contracts may be fixed at the time the purchase contracts are issued or may be determined by reference to a specific formula described in the purchase contracts. We may issue purchase contracts separately or as a part of units each consisting of a purchase contract and one or more of our other securities described in this prospectus or securities of third parties, including U.S. Treasury securities, securing the holder’s obligations under the purchase contract. The purchase contracts may require us to make periodic payments to holders or vice versa and the payments may be unsecured or pre-funded on some basis. The purchase contracts may require holders to secure the holder’s obligations in a manner specified in the applicable prospectus supplement.

The applicable prospectus supplement will describe the terms of any purchase contracts in respect of which this prospectus is being delivered, including, to the extent applicable, the following:

	●	whether the purchase contracts obligate the holder or us to purchase or sell, or both purchase and sell, the securities subject to purchase under the purchase contract, and the nature and amount of each of those securities, or the method of determining those amounts;

	●	whether the purchase contracts are to be prepaid;

	●	whether the purchase contracts are to be settled by delivery, or by reference or linkage to the value, performance or level of the securities subject to purchase under the purchase contract;

	●	any acceleration, cancellation, termination or other provisions relating to the settlement of the purchase contracts;

	●	any applicable U.S. federal income tax considerations; and

	●	whether the purchase contracts will be issued in fully registered or global form.

The preceding description sets forth certain general terms and provisions of the purchase contracts to which any prospectus supplement may relate. The particular terms of the purchase contracts to which any prospectus supplement may relate and the extent, if any, to which the general provisions may apply to the purchase contracts so offered will be described in the applicable prospectus supplement. To the extent that any particular terms of the purchase contracts described in a prospectus supplement differ from any of the terms described above, then the terms described above will be deemed to have been superseded by that prospectus supplement. We encourage you to read the applicable purchase contract for additional information before you decide whether to purchase any of our purchase contracts.

DESCRIPTION OF UNITS

The following description, together with the additional information that we include in any applicable prospectus supplements summarizes the material terms and provisions of the units that we may offer under this prospectus. While the terms we have summarized below will apply generally to any units that we may offer under this prospectus, we will describe the particular terms of any series of units in more detail in the applicable prospectus supplement. The terms of any units offered under a prospectus supplement may differ from the terms described below.

We will incorporate by reference from reports that we file with the SEC, the form of unit agreement that describes the terms of the series of units we are offering, and any supplemental agreements, before the issuance of the related series of units. The following summaries of material terms and provisions of the units are subject to, and qualified in their entirety by reference to, all the provisions of the unit agreement and any supplemental agreements applicable to a particular series of units. We urge you to read the applicable prospectus supplements related to the particular series of units that we may offer under this prospectus, as well as any related free writing prospectuses and the complete unit agreement and any supplemental agreements that contain the terms of the units.

General

We may issue units consisting of common stock, preferred stock, one or more debt securities, warrants, rights or purchase contacts for the purchase of common stock, preferred stock and/or debt securities in one or more series, in any combination. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each security included in the unit. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

We will describe in the applicable prospectus supplement the terms of the series of units being offered, including:

	●	the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

	●	any provisions of the governing unit agreement that differ from those described below; and

	●	any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units.

The provisions described in this section, as well as those set forth in any prospectus supplement or as described under “Description of Capital Stock,” “Description of Debt Securities,” “Description of Warrants,” “Description of Rights” and “Description of Purchase Contracts” will apply to each unit, as applicable, and to any common stock, debt security, warrant, right or purchase contract included in each unit, as applicable.

Unit Agent

The name and address of the unit agent for any units we offer will be set forth in the applicable prospectus supplement.

Issuance in Series

We may issue units in such amounts and in such numerous distinct series as we determine.

Enforceability of Rights by Holders of Units

Each unit agent will act solely as our agent under the applicable unit agreement and will not assume any obligation or relationship of agency or trust with any holder of any unit. A single bank or trust company may act as unit agent for more than one series of units. A unit agent will have no duty or responsibility in case of any default by us under the applicable unit agreement or unit, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a unit may, without the consent of the related unit agent or the holder of any other unit, enforce by appropriate legal action its rights as holder under any security included in the unit.

LEGAL MATTERS

Reed Smith LLP, New York, New York, will pass upon the validity of the issuance of the securities to be offered by this prospectus.

EXPERTS

Mayer Hoffman McCann P.C., our independent registered public accounting firm, has audited our balance sheets as of December 31, 2015 and 2014, and the related statements of operations, changes in securities subject to redemption and shareholders’ deficit and cash flows for each of the two years in the period ended December 31, 2015, as set forth in their report, which report expresses an unqualified opinion and includes an explanatory paragraph relating to our ability to continue as a going concern. We have incorporated by reference our financial statements in this prospectus and in this registration statement in reliance on the report of Mayer Hoffman McCann P.C. given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a Registration Statement on Form S-1 under the Securities Act in connection with this offering of our common stock by our selling stockholders. This Prospectus, which constitutes a part of the Registration Statement, does not contain all of the information set forth in the registration statement, some items of which are contained in exhibits to the Registration Statement as permitted by the rules and regulations of the SEC. For further information with respect to us and our common stock, we refer you to the Registration Statement, including the exhibits and the financial statements and notes filed as a part of the Registration Statement. Statements contained in this prospectus concerning the contents of any contract or any other document are not necessarily complete. If a contract or document has been filed as an exhibit to the Registration Statement, please see the copy of the contract or document that has been filed. Each statement in this prospectus relating to a contract or document filed as an exhibit is qualified in all respects by the filed exhibit. The exhibits to the Registration Statement should be referenced for the complete contents of these contracts and documents. A copy of the Registration Statement and the exhibits filed therewith may be inspected without charge at the public reference room of the SEC, located at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. You may obtain information on the operation of the public reference rooms by calling the SEC at 1-800-SEC-0330. The SEC also maintains an Internet website that contains reports, proxy statements, and other information about issuers, like us, that file electronically with the SEC. The address of that website is www.sec.gov.

We are subject to the information and reporting requirements of the Exchange Act and, in accordance with this law, we file periodic reports, proxy statements, and other information with the SEC. These periodic reports, proxy statements, and other information are available for inspection and copying at the SEC’s public reference facilities and the website of the SEC referred to above. We also maintain a website at www.ritterpharmaceuticals.com . You may access our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act with the SEC free of charge at our website (www.ritterpharmaceutical.com) as soon as reasonably practicable after such material is electronically filed with, or furnished to, the SEC. The information contained in, or that can be accessed through, our website is not incorporated by reference into this Prospectus.

INCORPORATION OF INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information that we file with them. Incorporation by reference allows us to disclose important information to you by referring you to those other documents. The information incorporated by reference is an important part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. This prospectus omits certain information contained in the registration statement, as permitted by the SEC. You should refer to the registration statement and any prospectus supplement filed hereafter, including the exhibits, for further information about us and the securities we may offer pursuant to this prospectus. Statements in this prospectus regarding the provisions of certain documents filed with, or incorporated by reference in, the registration statement are not necessarily complete and each statement is qualified in all respects by that reference. Copies of all or any part of the registration statement, including the documents incorporated by reference or the exhibits, may be obtained upon payment of the prescribed rates at the offices of the SEC listed above in “Where You Can Find More Information.” The documents we are incorporating by reference are:

	●	our Annual Report on Form 10-K for the fiscal year ended December 31, 2015 filed on March 21, 2016;

	●	our Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 2016, filed on May 9, 2016, and June 30, 2016, filed on August 8, 2016;

	●	our Current Reports on Form 8-K filed on January 5, 2016 and June 6, 2016; and

	●	the description of the Company’s Common Stock contained in the Company’ Registration Statement on Form 8-A (File No. 1-37428) filed on June 15, 2015, including any amendment or report filed for the purpose of updating such description

In addition, all documents that the Company files pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act of 1934, as amended (the “Exchange Act”), subsequent to the filing of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the date of filing of such documents, except as to any document or portion of any document that is deemed furnished and not filed.

Pursuant to Rule 412 under the Securities Act, any statement contained in the documents incorporated or deemed to be incorporated by reference in this Registration Statement shall be deemed to be modified, superseded or replaced for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is incorporated or deemed to be incorporated by reference in this Registration Statement modifies, supersedes or replaces such statement. Any such statement so modified, superseded or replaced shall not be deemed, except as so modified, superseded or replaced, to constitute a part of this Registration Statement.

2,127,660 Shares

Common Stock

PROSPECTUS SUPPLEMENT

Aegis Capital Corp

October 26 , 2016