Urea is a humectant referred to as hydroxyethyl urea not to be confused with the preservative sdiazolidinyl urea & imidazolidinyl urea which I discuss in more detail below. A healthy skin will typically contain 28 micrograms of urea per square centimetre a dehydrated dry skin can see a reduction of as much as 50% & those with eczema as much as 80%.