Perspective Therapeutics Inc Stock Offering Prospectus (February 3, 2026 Version)

39,576,088 Shares of Common Stock We are offering 39,576,088 shares of our common stock and, in lieu of common stock to certain investors, pre-funded warrants topurchase 6,598,046 shares of our common stock pursuant to this prospectus supplement and the accompanying prospectus. Thepurchase price of each pre-funded warrant will equal the price per share at which shares of our common stock are being sold in this Our common stock is traded on the NYSE American under the ticker symbol “CATX.” On January 30, 2026, the closing price ofour common stock was $3.79 per share. There is no established public trading market for the pre-funded warrants, and we do notexpect a market to develop. We do not intend to list the pre-funded warrants on the NYSE American or any other national securities (1)See the section entitled “Underwriting” beginning on page S-28 of this prospectus supplement for a description of thecompensation payable to the underwriters. (2)The amount of the offering proceeds to us presented in this table does not give effect to any exercise of the pre-fundedwarrants being issued in the offering. Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties referencedunder the section entitled“Risk Factors”on pageS-7of this prospectus supplement, page4of the accompanying prospectus Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. We expect to deliver the shares of common stock and/or pre-funded warrants against payment on or about February 3, 2026. ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of a “shelf” registration statement that we filed with theSecurities and Exchange Commission (the “SEC”). Under the shelf registration statement process, we may from time to time offerand sell any combination of the securities described in the accompanying prospectus of which this offering is a part in one or more This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering and also addsto and updates information contained in the accompanying prospectus and the documents incorporated by reference herein ortherein. The second part, the accompanying prospectus, including the documents incorporated by reference into the accompanyingprospectus, provides more general information. Generally, when we refer to this prospectus, we are referring to both parts of thisdocument combined. To the extent there is a conflict between the information contained in this prospectus supplement and theinformation contained in the accompanying prospectus or any document incorporated by reference herein or therein filed prior to the We have not, and the underwriters have not, authorized anyone to provide information different from that contained in thisprospectus supplement, the accompanying prospectus and any free writing prospectus that we have authorized for use in thisoffering. Neither we nor the underwriters take any responsibility for, and can provide no assurance as to the reliability of, any otherinformation that others may give you. Neither we nor the underwriters will make an offer to sell or solicit an offer to buy thesesecurities in any jurisdiction where the offer or sale is not permitted. Neither the delivery of this prospectus supplement, theaccompanying prospectus and any free writing prospectus that we have authorized for use in this offering, nor the sale of our This prospectus supplement does not contain all of the information that is important to you. You should also read andconsider the information in the documents to which we have referred you in the sections entitled“Where You Can FindMore Information”and“Incorporation of Certain Information by Reference”in this prospectus supplement. You should We are offering to sell, and seeking offers to buy, and the underwriters are soliciting offers to buy, these securities only injurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectusand the offering of the securities in certain jurisdictions may be restricted by law. Persons outside the United States who come intopossession of this prospectus supplement and the accompanying prospectus must inform themselves about, and observe anyrestrictions relating to, the offering of the securities and the distribution of this prospectus supplement and the accompanying Unless the context requires otherwise, in this prospectus supplement the terms “Perspective Therapeutics,” “the Company,” “we,”“us,” “our,” and similar terms refer to Perspective Therapeutics, Inc. and its wholly owned subsidiaries. “Perspective Therapeutics” and the Perspective Therapeutic