[424B5] RedHill Biopharma Ltd. Prospectus Supplement (Debt Securities)

Rhea-AI Filing Summary

RedHill Biopharma Ltd. is increasing the maximum aggregate amount of American Depositary Shares it may sell under its at-the-market offering agreement with H.C. Wainwright & Co. to $352,267. Each ADS represents ten thousand Ordinary Shares, and this new limit applies only to future sales under the existing Sales Agreement.

As of this supplement, the company’s public float under Form F-3 was valued at $11,448,803.52, based on 45,431,765,990 Ordinary Shares held by non-affiliates, which would be represented by 4,543,176 ADSs at a price of $2.52 per ADS as of October 1, 2025. Over the prior 12 months, RedHill sold 890,001 ADSs via the program for approximately $3.4 million in gross proceeds, and any further increases in sale capacity will require an additional prospectus supplement.

Filed pursuant to Rule 424(b)(5)

Registration No. 333-281417

PROSPECTUS SUPPLEMENT

(To Prospectus Supplement dated February 3, 2025, to Prospectus dated August 19, 2024)

Up to $352,267

American Depositary Shares each representing ten thousand (10,000) Ordinary Shares

RedHill Biopharma Ltd.

This prospectus supplement dated November 26, 2025 (this “Prospectus Supplement”), supplements the information in the prospectus, dated August 19, 2024, forming a part of our registration statement on Form F-3 (Registration No. 333-281417) that we filed with the Securities and Exchange Commission on August 9, 2024, as supplemented by our prospectus supplement dated February 3, 2025 (collectively, the “Prospectus”). This Prospectus Supplement should be read in conjunction with the Prospectus, and is qualified by reference thereto, except to the extent that the information herein amends or supersedes the information contained in the Prospectus. This Prospectus Supplement is not complete without, and may only be delivered or utilized in connection with, the Prospectus, and any future amendments or supplements thereto. This Prospectus Supplement supplements or amends only those sections of the Prospectus identified in this Prospectus Supplement; all other sections of the Prospectus remain unchanged.

The Prospectus, as supplemented by this Prospectus Supplement, relates to the offering, issuance and sale by us of shares of American Depositary Shares (the “ADSs”), each representing ten thousand (10,000) of our ordinary shares (“Ordinary Shares”), par value NIS 0.01 per share, that may be issued and sold from time to time under the At The Market Offering Agreement, that we entered into with H.C. Wainwright & Co., LLC (“Wainwright”), on February 3, 2025 (the “Sales Agreement”).

We are filing this Prospectus Supplement to supplement and amend the Prospectus to increase the maximum aggregate offering amount of the ADSs that may be offered, issued and sold under the Sales Agreement from and after the date hereof to $352,267, which such amount does not include the ADSs previously sold pursuant to the Sales Agreement and the Prospectus.

As of the date of this Prospectus Supplement, the aggregate market value of our outstanding Ordinary Shares held by non-affiliates pursuant to General Instruction I.B.5 of Form F-3 is $11,448,803.52, based on 45,431,765,990 Ordinary Shares outstanding held by non-affiliates (which would be represented by 4,543,176 ADSs), and a per ADS price of $2.52 per ADS, the closing price of the ADSs on October 1, 2025, as reported on the Nasdaq Capital Market (“Nasdaq”). As of the date hereof, we have sold 890,001 ADSs under the Sales Agreement for aggregate gross proceeds of approximately $3.4 million pursuant to General Instruction I.B.5 of Form F-3 during the 12 calendar months prior to and including the date of this Prospectus Supplement. Pursuant to General Instruction I.B.5 of Form F-3, in no event will we sell securities pursuant to the registration statement of which this Prospectus Supplement forms a part in a public primary offering with a value exceeding one-third of our outstanding voting and non-voting common equity held by non-affiliates (the “public float”) in any 12 calendar month period so long as our public float remains below $75.0 million. In the event that we may sell additional amounts under the Sales Agreement, we will file another prospectus supplement prior to making such additional sales.

The ADSs are listed on Nasdaq under the symbol “RDHL.” On November 25, 2025, the last reported sale price of the ADSs on Nasdaq was $1.11 per ADS.

Investing in our securities involves a high degree of risk. Please read “Risk Factors” beginning on page S-8 of the prospectus supplement dated February 3, 2025, on page 5 of the prospectus, dated August 19, 2024, and under similar headings in the documents incorporated by reference into such prospectus supplement and prospectus.

None of the United States Securities and Exchange Commission, any state securities commission or any other regulatory body, has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying base prospectus. Any representation to the contrary is a criminal offense.

H.C. Wainwright & Co.

The date of this Prospectus Supplement is November 26, 2025.