How urea changes what skin cells do

This study asked what urea actually does inside skin, rather than whether it works. In twenty-one volunteers, topical urea improved barrier function and increased production of the skin's own antimicrobial peptides. The researchers showed urea is not passively soaking in — it is carried into skin cells by specific transporter proteins, and blocking those transporters blocks the effect. Once inside, urea raised production of filaggrin, loricrin and the enzymes that build barrier fats. This matters because it separates urea from ordinary humectants. Most water-binding ingredients sit in the outer layer and hold moisture. Urea does that and also changes what the cells beneath are making. Some of the authors sit on a scientific advisory board for a company selling urea products, which is disclosed.