Company: GANX
Filing Date: 2025-07-15
Form Type: 424B5
Source: 0001104659-25-068103
Chunk: 28

Company: Gain Therapeutics, Inc.
Filing Date: 2025-07-15
Form: 424B5
Chunk 28
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 expenses to us.

| ​                                         | ​ | ​ | Effective PricePer Share andaccompanyingCommonWarrant |   |     |   | ​ | ​ | Effective PricePer Pre-FundedWarrant andaccompanyingCommon Warrant |   |     |   | ​ | ​ | Total WithoutOption | ​ | ​ | Total WithOption | ​ |
|:------------------------------------------|:--|:--|:------------------------------------------------------|:--|:----|:--|:--|:--|:-------------------------------------------------------------------|:--|:----|:--|:--|:--|:--------------------|:--|:--|:-----------------|:--|
| Public offering price(1)(2)               | ​ | ​ | ​                                                     | $ |     | ​ | ​ | ​ | ​                                                                  | $ |     | ​ | ​ | ​ | ​                   | ​ | ​ | ​                | ​ |
| Underwriting discounts and commissions(2) | ​ | ​ | ​                                                     | $ |     | ​ | ​ | ​ | ​                                                                  | $ |     | ​ | ​ | ​ | ​                   | ​ | ​ | ​                | ​ |
| Proceeds, before expenses, to us          | ​ | ​ | ​                                                     | $ |     | ​ | ​ | ​ | ​                                                                  | $ |     | ​ | ​ | ​ | ​                   | ​ | ​ | ​                | ​ |

(1) Based on a price of $ per set of two shares of common stock and one accompanying Common Warrant to purchase one share of common stock, including $ per accompanying whole Common Warrant. (2) Based on a price of $ per set of two Pre-Funded Warrants and one accompanying Common Warrant to purchase one share of common stock, including $ per accompanying whole Common Warrant. (3) The underwriting discount is 7.0% of the gross proceeds received from the sale of the securities in the offering. Over-Allotment Option In addition to the discount set forth in the above table, we have granted to the underwriter an option, exercisable not later than 30 days after the date of this prospectus supplement, to purchase up to a number

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of additional shares of common stock equal to 15% of the shares of common stock and Pre-Funded Warrants sold in this offering and/or a number of additional Common Warrants equal to 15% of the Common W