Urea is one of the components of a natural moisturizing factor (NMF), that is present in all tissues and fluids in human body. Together with the aging process, the concentration of urea in the epidermis decreases. Urea may also be obtained by a chemical process. It is then non-toxic and hypoallergenic so it may be used for cosmetic purposes.
Urea binds water in the epidermis improving its hydration and elasticity; urea works on calloused skin cells having softening and moisturizing effect.
Depending on the concentration of urea in skin care products, its functions are different:
- 2-5% – visible hydration
- 5-10% – optimal hydration, facilitates binding of water through the skin
- 10% and more – intensive keratolytic (exfoliating) action