Urea is a substance naturally created by the human body through protein metabolism and is also a component of the natural moisturizing factor (NMF) produced by the skin. It is a humectant, which means it is able to absorb moisture and draw it into the skin. In nail and skin care products, it is used to help moisturize dry skin, as well as act as a chemical exfoliator (if the product contains more than 10%).