Epidermal permeability barrier function

The **epidermal permeability barrier** is a physiological property rather than a discrete molecular target. It refers to the skin’s ability—primarily through the outermost layer called the stratum corneum—to regulate water loss from inside the body and prevent entry of harmful substances from outside. This function is achieved by multiple lipid bilayers composed mainly of ceramides, cholesterol, and free fatty acids that fill intercellular spaces between dead keratinocytes (corneocytes). These lipids are derived from lamellar granules produced by keratinocytes in deeper epidermal layers. The acidic pH at the skin surface supports enzymatic processes essential for forming these lipids and maintaining an effective barrier. Disruption leads to increased transepidermal water loss, heightened inflammatory responses both locally and systemically, greater risk for infections due to impaired antimicrobial peptide expression, and has been associated with various dermatological conditions as well as systemic diseases linked to chronic inflammation.

Other names

Skin barrierStratum corneum permeability barrierEpidermal barrier function

Restoration or enhancement of lipid bilayer integrity in the stratum corneum