Company: GANX
Filing Date: 2025-11-07
Form Type: S-3/A
Source: 0001104659-25-108472
Chunk: 1

Company: Gain Therapeutics, Inc.
Filing Date: 2025-11-07
Form: S-3/A
Chunk 1
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 of the earlier effective registration statement for the same offering. ☐ If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ☐ If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act. ☐

| ​ | Large accelerated filer: 
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 ​                        | ​ | ​ | Accelerated filer:         
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| ​ | Non-accelerated filer:   
 ☒                        
 ​                        | ​ | ​ | Smaller reporting company: 
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| ​ | ​                        | ​ | ​ | Emerging growth company:   
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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 7(a)(2)(B) of Securities Act. ☐ This registration statement shall hereafter become effective in accordance with the provisions of Section 8(a) of the Securities Act of 1933.

TABLE OF CONTENTS

**The information in this prospectus is not complete and may be changed. A registration statement relating to these securities has been filed with the Securities and Exchange Commission. These securities may not be sold until the registration statement is declared effective. This prospectus is not an offer to sell these securities, and is not soliciting an offer to buy these securities, nor shall there be any sale of these securities, in any state or other jurisdiction where such offer, solicitation or sale is not permitted or would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction.**

#### Subject to completion, dated November 7, 2025

### PRELIMINARY PROSPECTUS