SEC Form 424B3 filed by Jupiter Neurosciences Inc.

Filed pursuant to Rule 424(b)(3)

Registration No. 333-291832

Prospectus Supplement No. 6

(To Prospectus dated December 11, 2025)

Jupiter Neurosciences, Inc.

This prospectus supplement updates, amends and supplements the prospectus dated December 11, 2025 (the “Prospectus”), which forms a part of our Registration Statement on Form S-1 (Registration No. 333-291832) and is being filed to update, amend and supplement the information included in the Prospectus with information contained in our Current Report on Form 8-K, which was filed with the Securities and Exchange Commission (the “SEC”) on June 22, 2026 (the “Current Report”). Accordingly, we have attached the Current Report to this prospectus supplement. Capitalized terms used in this prospectus supplement and not otherwise defined herein have the meanings specified in the Prospectus.

This prospectus supplement is not complete without the Prospectus. This prospectus supplement should be read in conjunction with the Prospectus, which is to be delivered with this prospectus supplement, and is qualified by reference thereto, except to the extent that the information in this prospectus supplement updates or supersedes the information contained in the Prospectus. Please keep this prospectus supplement with your Prospectus for future reference.

Shares of our common stock, par value $0.0001 per share (our “Common Stock”), are listed on The Nasdaq Stock Market, LLC under the symbol “JUNS.” On June 18, 2026, the closing price of our Common Stock was $0.2380 per share.

Investing in our securities involves risks that are described in the “Risk Factors” section of the Prospectus.

Neither the SEC nor any state securities commission has approved or disapproved of the securities to be issued under the Prospectus or this prospectus supplement or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is June 22, 2026.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

June 17, 2026

Date of Report (Date of earliest event reported)

JUPITER NEUROSCIENCES, INC.

(Exact name of registrant as specified in its charter)

(561) 406-6154

Registrant’s telephone number, including area code

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the 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 for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On June 17, 2026, Allison W. Brady, a member of the Board of Directors (the “Board”) of Jupiter Neurosciences, Inc. (the “Company”), informed the Company of her decision to resign from the Board, effective immediately. Ms. Brady also resigned from her positions as a member of the Audit Committee and the Compensation Committee of the Board, effective as of the same date. Her decision to resign is not the result of any disagreement with the Company on any matter relating to the Company’s operations, policies or practices. Ms. Brady’s seat on the Board will remain vacant until the Company’s annual meeting on July 22, 2026.

Item 9.01. Financial Statements and Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.