Component of urine, although synthetic versions are used in cosmetics. In small amounts urea has good water-binding and exfoliating properties for skin; in larger concentrations it can cause inflammation.
- Wohlrab J, Siemes C, Marsch W. The influence of L-arginine on the regulation of epidermal arginase. Skin Pharmacol Appl Skin Physiol. 2002;15(1):44-54.