Azelaic acid is a dicarboxylic acid that exhibits anti-inflammatory activity. It is known for it's anti acne activity in vitro. Azelaic acid directly inhibits kallikrein 5 (KLK5), downregulating expression of KLK5, toll-like receptor 2 (TLR 2), and cathelicidin, and suppresses activity of serine proteases in vitro, in vivo, and in clinical settings. In PUFA-treated fibroblasts, azelaic acid decreases generation of ROS and upregulates expression of antioxidative enzymes, inhibiting cell damage; agonist activity at PPARν is thought to drive these effects. Azelaic acid also inhibits proliferation of melanocytes. This compound displays antiacne and anticancer potential as well, inhibiting the proliferation of cutaneous melanoma due to suppression of mitochondrial oxidoreductive activity and DNA synthesis.