Urea, like glycerol and amino acids, is a component of the skin's moisture retention system. As substance naturally found in the human body, it is especially compatible with other substances. For cosmetics, it is manufactured synthetically and often used to treat eczema, psoriasis and cornification disorders. Urea is water-binding and loosens dead skin cells. Thus, it makes sebum flow easier, which is especially important in clearing up oily, blemished skin. In higher concentrations, urea also has slight antibacterial and anti-itching properties. Another characteristic of urea is its absorption enhancing the effect, in that it improves the capacity of the skin to absorb moisture. Moreover, the skins' natural barrier function is supported by urea's properties.
see: Heike Käser 2010 "Natural Cosmetic Raw Materials", Linz, Freya Verlag, 3rd Edition 2012