Tranexamic acid is obtained from lysine, which is an amino acid. Earlier, the conventional use the acid was used to treat heavy menstrual bleeding. However, when you use the same topically, it modifies the way melanin is produced by the cells. Melanin is responsible for skin color. So, more about the essential features of the acid are described here. 
https://businessupside.com/2022/05/10/tranexamic-acid-who-is-eligible-to-use-it-benefits-and-takeaway/