ProPhase Labs Inc美股招股说明书(2025-10-06版)

PROPHASE LABS, INC. This prospectus supplement is being filed to update and supplement the information contained in the prospectus dated November 20,2024 (the “Prospectus”), as previously supplemented by the prospectus supplement filed January 30, 2025, filed by ProPhase Labs,Inc. (the “Company,” “we,” “our,” or “us”) with the information contained in the Company’s current report on Form 8-K, filed withthe Securities and Exchange Commission on August 28, 2025. Accordingly, we have attached the Company’s Current Report on Form8-K to this prospectus supplement. This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not bedelivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectussupplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in theProspectus and this prospectus supplement, you should rely on the information in this prospectus supplement. Our common stock is listed on the Nasdaq Capital Markets (the “Nasdaq”) under the symbol “PRPH.” On October 3, 2025, the lastreported sales price for our common stock was $0.56. INVESTINGIN OUR SECURITIES INVOLVES RISKS.WE STRONGLY RECOMMEND THAT YOU READCAREFULLY THE RISKS WE DESCRIBE IN THIS PROSPECTUS SUPPLEMENT AND THE ACCOMPANYING BASEPROSPECTUS, AS WELL AS THE RISK FACTORS THAT ARE INCORPORATED BY REFERENCE INTO THISPROSPECTUS SUPPLEMENT AND THE ACCOMPANYING BASE PROSPECTUS FROM OUR FILINGS MADE WITHTHE SECURITIES AND EXCHANGE COMMISSION. SEE “RISK FACTORS” BEGINNING ON PAGE 3 OF THE BASEPROSPECTUS. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved thesecurities we may be offering or determined if this prospectus is accurate or complete. Any representation to the contrary is acriminal offense. The date of this prospectus supplement is October 6, 2025. UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) ofThe Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 28, 2025 PROPHASE LABS, INC. (Exact name of Company as specified in its charter) 11556(Zip Code) Registrant’s telephone number, including area code:(516) 989-0763 Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the Companyunder any of the following provisions (seeGeneral Instruction A.2. below): Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities Registered Pursuant to Section 12(b) of the Exchange Act: Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933(§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐ Item 1.02. Termination of a Material Definitive Agreement. On August 27, 2025, ProPhase Labs, Inc. (the “Company”) delivered notice to Keystone Capital Partners, LLC (“Keystone”) toterminate, effective the next trading day, the Common Stock Purchase Agreement dated January 29, 2025, between the Company andKeystone (the “Keystone Agreement”). Pursuant to such notice, the Keystone Agreement terminated effectively on Thursday, August28, 2025. The Keystone Agreement established an equity line of credit facility under which the Company had the right, but not the obligation, tosell shares of its common stock to Keystone up to an aggregate purchase price of approximately $7.7 million. The KeystoneAgreement provided that the Company could terminate the facility at any time, in its sole discretion, upon one trading day’s priorwritten notice, without cost or penalty. The Company terminated the Keystone Agreement in its sole discretion and incurred nopenalties or termination fees in connection with the termination. Other than the Keystone Agreement, there are no materialrelationships between the Company or its affiliates and Keystone. Item 9.01 Financial Statements and Exhibits. (d) Exhibits No.Description10.1Termination Notice to Keystone Capital Partners, LLC104Cover Page Interactive Data File (embedded within the Inline XBRL document) Pursuant to the requirements of the Securities Exchange Act of 1934, the Company has du