Spruce Biosciences Inc美股招股说明书(2026-04-21版)

1,150,000 Shares of Common Stock Pre-Funded Warrants to Purchase 50,000 Shares of Common Stock We are offering 1,150,000 shares of our common stock, par value $0.0001 per share, or in lieu of common stock to certain investorsthat so choose, pre-funded warrants to purchase shares of our common stock. The purchase price of each pre-funded warrant equalsthe price per share at which shares of our common stock are being sold to the public in this offering, minus $0.01, and the exerciseprice of each pre-funded warrant is $0.01 per share. We are also offering shares of our common stock that are issuable from time totime upon the exercise of the pre-funded warrants. There is no established public trading market for the pre-funded warrants, and we do not expect a market to develop. We do notintend to apply for listing of the pre-funded warrants on the Nasdaq Capital Market or other securities exchange or nationallyrecognized trading system. Without an active trading market, the liquidity of the pre-funded warrants will be limited. Our common stock is listed on the Nasdaq Capital Market under the symbol “SPRB.” The last reported sale price of our commonstock on the Nasdaq Capital Market on April 20, 2026 was $69.89 per share. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-7 of this prospectussupplement, page 6 of the accompanying prospectus and under similar headings in the documents incorporated byreference into this prospectus supplement and the accompanying prospectus. We are a “smaller reporting company” under applicable Securities and Exchange Commission rules and as such, have elected tocomply with reduced public company reporting requirements. See “Prospectus Supplement Summary — Implications of Being aSmaller Reporting Company.” 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. Delivery of shares of common stock and pre-funded warrants is expected to be made on or about April 22, 2026. We have granted the underwriters an option for a period of 30 days to purchase up to an additional 180,000 shares of our commonstock at the public offering price, less the underwriting discounts and commissions. If the underwriters exercise the option in full,the total underwriting discounts and commissions payable by us will be $4,140,000, and the total proceeds to us, before expenses,will be $64,859,500. Table of Contents TABLE OF CONTENTS Prospectus SupplementPageABOUT THIS PROSPECTUS SUPPLEMENTS-1SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSS-2PROSPECTUS SUPPLEMENT SUMMARYS-4THE OFFERINGS-5RISK FACTORSS-7USE OF PROCEEDSS-10DIVIDEND POLICYS-11DILUTIONS-12DESCRIPTION OF SECURITIES WE ARE OFFERINGS-14MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS OF OUR COMMON STOCK AND PRE-FUNDEDWARRANTSS-17UNDERWRITINGS-21LEGAL MATTERSS-27EXPERTSS-27WHERE YOU CAN FIND MORE INFORMATIONS-27INCORPORATION OF CERTAIN INFORMATION BY REFERENCES-28ProspectusPageABOUT THIS PROSPECTUS1PROSPECTUS SUMMARY2RISK FACTORS6SELECTED FINANCIAL DATA REFLECTING REVERSE STOCK SPLIT7SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS9USE OF PROCEEDS10DESCRIPTION OF CAPITAL STOCK11DESCRIPTION OF DEBT SECURITIES15DESCRIPTION OF WARRANTS22LEGAL OWNERSHIP OF SECURITIES25PLAN OF DISTRIBUTION29LEGAL MATTERS32EXPERTS32WHERE YOU CAN FIND MORE INFORMATION32INCORPORATION OF CERTAIN INFORMATION BY REFERENCE32 ABOUT THIS PROSPECTUS SUPPLEMENT This document is part of a “shelf” registration statement on Form S-3 that we filed with the Securities and Exchange Commission(the “SEC”) and is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering ofour common stock and pre-funded warrants and also adds to and updates information contained in the accompanying prospectusand the documents incorporated by reference herein and therein. The second part, the accompanying prospectus, provides moregeneral information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To theextent there is a conflict between the information contained in this prospectus supplement and the information contained in theaccompanying prospectus or any document incorporated by reference into this prospectus supplement or the accompanyingprospectus filed prior to the date of this prospectus supplement, you should rely on the information in this prospectus supplement;provided that if any statement in one of these documents is inconsistent with a statement in another document having a later date —for example, a document incorporated by reference into this prospectus supplement — the statement in the document having thelater date modifies or supersedes the earlier statement. We further note th