Tranexamic Acid 3% (PLG inhibitor)

Originally developed and still used medically as an anti-fibrinolytic (it controls bleeding by inhibiting plasminogen activation). Its dermatological use is a repurposed application of the same core mechanism.

Melasma and inflammation-driven hyperpigmentation involve keratinocytes activating plasminogen, which triggers a cascade that stimulates melanocytes to overproduce melanin. Tranexamic acid inhibits plasminogen activation in the skin, interrupting that inflammatory-to-pigment cascade. This is a genuinely different mechanism from azelaic acid's enzymatic (tyrosinase) approach.

Combining azelaic acid (enzymatic blocking) with tranexamic acid (inflammatory pathway blocking) targets melanin production through two independent biological routes at once. That makes duo-therapy a mechanistically justified description, not just two actives bundled together.