OS Therapies Inc美股招股说明书(2025-09-30版)

OS THERAPIES INCORPORATEDCommon Stock This prospectus supplement covers up to 4,373,043 shares of common stock of OS Therapies Incorporated that may beoffered for resale or otherwise disposed of by the selling stockholders set forth under the caption “Selling Stockholders” beginning onpageS-10 of this prospectus supplement, including their respective pledges, assignees and successors-in-interest. The shares of common stock being offered for resale under this prospectus supplement consist of (i) 3,373,043 shares ofcommon stock issuable upon exercise of the New Warrants as described under the caption “Description of the Warrant ExerciseInducement and Exchange Offer” and (ii) 1,000,000 shares of common stock to accommodate tax and estate planning of an executiveofficer of our company. We will not receive any proceeds from the sale of shares by the selling stockholders. We will, however,receive proceeds from any cash exercise of the New Warrants. We will bear all costs, expenses and fees in connection with theregistration of shares for resale by the selling stockholders. The selling stockholders will each bear their respective discounts,commissions, fees of underwriters, selling brokers or dealer managers and similar expenses, if any, attributable to the sale ordisposition of the shares, or interests therein, held by such selling stockholder. See “Use of Proceeds” beginning on pageS-7 of thisprospectus supplement for more information. The selling stockholders may offer all or part of the shares registered hereby for resale from time to time through public orprivate transactions, at either prevailing market prices or at privately negotiated prices. Our registration of the shares covered by thisprospectus supplement does not mean that the selling stockholders will offer or sell any of the shares. With regard only to the sharesthe selling stockholders sell for their own behalf, such selling stockholder may be deemed an “underwriter” within the meaning of theSecurities Actof1933, as amended (the “Securities Act”). See “Plan of Distribution” beginning on pageS-11 of this prospectussupplement for more information. Our common stock is traded on the NYSE American under the symbol “OSTX.” On September 29, 2025, the closing price ofour common stock on the NYSE American was $1.98 per share. You should read this prospectus, together with additional information described under the headings “Where You Can FindMore Information” and “Incorporation of Certain Information by Reference,” carefully before you invest in our common stock. Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-6 of thisprospectus supplement and page 3 of the accompanying base prospectus, as well as the information under the heading “RiskFactors” in our Annual Report on Form 10-K for the year ended December 31, 2024, and in the other documents incorporatedby reference into this prospectus supplement and the accompanying base prospectus for a discussion of the factors you shouldcarefully consider before investing in our common stock. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthese securities or determined if this prospectus supplement or the accompanying base prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. Prospectus Supplement datedSeptember 30, 2025 TABLE OF CONTENTS Prospectus Supplement PageAbout this Prospectus SupplementS-iiSpecial Note Regarding Forward-Looking StatementsS-iiiProspectus Supplement SummaryS-1Summary of the OfferingS-5Risk FactorsS-6Use of ProceedsS-7Description of the Warrant Exercise Inducement and Exchange OfferS-8Selling StockholdersS-10Plan of DistributionS-11Legal MattersS-13ExpertsS-13Where You Can Find More InformationS-13Incorporation of Certain Information by ReferenceS-14 Prospectus PageABOUT THIS PROSPECTUSiiABOUT THE COMPANY1RISK FACTORS3CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS4USE OF PROCEEDS5DESCRIPTION OF OUR CAPITAL STOCK6DESCRIPTION OF OUR DEBT SECURITIES12DESCRIPTION OF OUR WARRANTS18DESCRIPTION OF OUR RIGHTS22DESCRIPTION OF OUR UNITS23PLAN OF DISTRIBUTION24SELLING STOCKHOLDERS29LEGAL MATTERS30EXPERTS30WHERE YOU CAN FIND MORE INFORMATION30INCORPORATION OF CERTAIN INFORMATION BY REFERENCE31 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 that we filedwith the Securities and Exchange Commission (the “SEC”) using a “shelf” registration process and consists of two parts. The first partis this prospectus supplement, which describes the specific terms of this offering and also supplements and updates informationcontained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and theaccompanying prospectus. The second part is the accompanying prospectus, which provides more general info