Ceramides are a type of lipid naturally present in the outermost layer of the epidermis. In cohesion with other lipids such as cholesterol, ceramides form the cutaneous barrier, whose role is to limit transepidermal water loss. The cutaneous barrier is essential for maintaining the skin's moisture level and protecting it from external aggression.

Whether synthetic or plant-based, ceramides are highly prized in cosmetics for their role in reinforcing the cutaneous barrier and preventing dehydration.

Ceramides are also alpha-hydroxy acids (AHAs): their exfoliating action stimulates cell renewal, smoothing skin texture and unclogging pores.