Outlook Therapeutics Inc. 美股招股说明书（2026-05-29版）

Pursuant to this prospectus supplement and accompanying prospectus, we are offering 8,539,709 shares of our common stock, parvalue $0.01 per share, to a single accredited institutional investor, or the purchaser. The offering price for each share of common stock In connection with, and effective upon the closing of, this offering, we have agreed to amend the terms of outstanding warrants, orthe amended warrants, to purchase up to an aggregate of 15,488,570 shares of common stock previously issued to the purchaser inJanuary2025 and May 2025, with a weighted average exercise price of$1.78per share, such that the amended warrants will have a Our common stock is traded on The Nasdaq Capital Market under the symbol “OTLK.” On May 27, 2026, the last reported sale We are a “smaller reporting company” under the federal securities laws and are subject to reduced public company reportingrequirements. See the section entitled “Prospectus Supplement Summary—Implications of Being a Smaller Reporting Company.” Investing in our securities involves a high degree of risk. Before making an investment decision, please read theinformation in “Risk Factors” beginning on pageS-8 of this prospectus supplement and in our filings incorporated by 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 prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. Delivery of the securities to the purchaser is expected on or about May 29, 2026, subject to satisfaction of customary closingconditions. Prospectus supplement dated May 28, 2026. PROSPECTUS SUPPLEMENT Page ABOUT THIS PROSPECTUS SUPPLEMENTS-iiSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSS-iii ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus relate to the offering of our securities. Before buying any of thesecurities that we are offering, we urge you to carefully read this prospectus supplement and the accompanying prospectus, togetherwith the information incorporated by reference as described in the section titled “Incorporation of Certain Information by Reference” This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering of oursecurities and also adds to and updates information contained in the accompanying prospectus and the documents incorporated byreference into this prospectus supplement and the accompanying prospectus. The second part, the accompanying prospectus datedApril5, 2024, including the documents incorporated by reference therein, provides more general information. Generally, when werefer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between theinformation contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus We have not authorized anyone to provide you with information different than or inconsistent with the information contained in orincorporated by reference into this prospectus supplement, the accompanying prospectus or in any free writing prospectus that we haveauthorized for use in connection with this offering. We do not take responsibility for, and can provide no assurance as to the reliabilityof, any other information that others may give you. We are not making an offer to sell these securities in any jurisdiction where theoffer or sale is not permitted. You should assume that the information appearing in this prospectus supplement, the accompanyingprospectus, the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, and in anyfree writing prospectus that we have authorized for use in connection with this offering, is accurate only as of the date of thoserespective documents, regardless of the time of delivery of those respective documents. Our business, financial condition, results of Except as otherwise indicated herein or as the context otherwise requires, references in this prospectus supplement, theaccompanying prospectus and the information incorporated by reference herein and therein to “Outlook,” “the company,” “we,” “us,” This prospectus supplement, the accompanying prospectus, and the information incorporated herein and therein by referenceinclude trademarks, trade names and service marks owned by us or other companies. The Outlook logo, Oncobiologics logo,LYTENAVA and other trademarks or service marks of Outlook Therapeutics,Inc. appearing in this prospectus supplement, theaccompanyingprospectus,and the information incorporated herein and therein by reference are the property of OutlookTherapeutics,Inc.This prospectus supplement, the accompanying prospectus, and the information incorporated herein and therein by SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS This prospectu