Identity
a synthetic lysine (amino-acid) analogue — trans-4-(aminomethyl)cyclohexanecarboxylic acid — originally developed as an antifibrinolytic medication to reduce bleeding. In skincare it is used as a small, stable, water-soluble topical active, typically at 2–5%, valued for its effect on the appearance of hyperpigmentation. For the full readable explanation of what it is and how it works, see the companion guide, what is tranexamic acid?
Development & history
- Developed in the mid-20th century as an antifibrinolytic medication (to reduce bleeding), still used medically in that role.
- Its effect on skin was discovered incidentally: melasma patients taking oral tranexamic acid noticed their pigmentation lightened.
- That observation drove interest in a topical cosmetic form, which grew into a mainstream brightening ingredient through the 2010s, often paired with niacinamide and vitamin C in tone-evening formulas.
Mechanism (as proposed)
it works primarily by inhibiting plasmin formation, which interrupts the UV-driven cascade (UV → plasmin → arachidonic acid → prostaglandins → melanocyte activation) that stimulates excess melanin. It may also modestly reduce tyrosinase activity, and has an anti-angiogenic effect that addresses the vascular, redness component of melasma. The net cosmetic action is to calm the triggers of pigment rather than to bleach existing pigment — which is why results are gradual and depend heavily on daily sun protection.