Azelaic Acid

Dicarboxylic acid from wheat, rye, and barley. Dual-action: antibacterial for acne-causing bacteria AND tyrosinase inhibitor for brightening. Safe during pregnancy. At 10–15% shows clinical evidence for rosacea and acne. Gained K-Beauty popularity in the 4th Wave as an alternative for sensitive skin unable to tolerate retinol or high-dose AHAs.