Epidermal hydration maintenance

Epidermal hydration maintenance refers to the collection of molecular and structural mechanisms that prevent dehydration of the outermost layers of the skin (primarily the stratum corneum)[1][3][5][7]. Major contributors include: - Natural moisturizing factors (NMFs): Hygroscopic molecules (including amino acids, urea, lactic acid, PCA) inside corneocytes that retain water[1][3][6][7]. - Stratum corneum intercellular lipids: Lamellar structures composed of ceramides, cholesterol, and free fatty acids that limit water loss to the outside environment[5][7]. - Aquaporin-3: A membrane channel protein transporting water and glycerol across keratinocyte membranes, critical for epidermal moisture distribution and barrier function[1][2][3][6]. - Hyaluronan: Present in the epidermis and dermis, contributes to water binding and maintaining healthy skin structure[3][6]. - Hydrolipid film and pH: Surface emulsion and acid mantle further minimize water loss and support enzymatic function for proper desquamation[1][5][7]. - Corneocyte structure and keratin filaments: Water uptake affects corneocyte swelling and viscoelastic properties of the skin[4][5]. “Epidermal hydration maintenance” is not a single, druggable molecular target but a skin function dependent on a constellation of proteins (e.g., aquaporin-3), lipids, endogenous humectants, and structural features[1][3][5]. Multiple drug classes—including moisturizers (occlusives, humectants, emollients), barrier repair agents, and some topical pharmaceuticals—affect these components, but no drug acts on a receptor or enzyme named “epidermal hydration maintenance.” Markers such as TEWL and corneometer readings are used to monitor this process. Defects contribute to common dermatological disorders such as xerosis and atopic dermatitis.

Other names

Skin hydration maintenanceMaintenance of epidermal hydrationHydration of the stratum corneumMoisturization