Cholesterol is a type of fat and, together with free fatty acids and sphingolipids such as ceramides, is a major component of the lipid fraction of the stratum corneum. Healthy skin synthesizes cholesterol on its own in the epidermis.

Following a disruption of the skin barrier, the early phase of repair is characterized by an increase in fatty acid and cholesterol biosynthesis, followed by epidermal sphingolipid synthesis. This highlights the importance of these epidermal lipids for the integrity and function of the skin barrier.(1)