Stratum corneum (skin moisture barrier)

The **skin moisture barrier** refers to the outermost layer of the epidermis—primarily the **stratum corneum**—which acts as a selectively permeable shield that prevents excessive water loss from the body while protecting underlying tissues from environmental insults such as pathogens, chemicals, allergens, and mechanical stress[1][2][4]. The stratum corneum is composed mainly of dead keratin-filled cells called *corneocytes* ("bricks") embedded in a lipid matrix ("mortar") made up primarily of ceramides, cholesterol, and fatty acids. This structure is further supported by proteins like filaggrin and involucrin that help maintain its integrity[2][3][5]. The skin moisture barrier is not a single molecule or receptor but rather a complex physical structure essential for maintaining hydration and overall skin health. It also plays roles in immune defense by supporting an acidic environment hostile to pathogens while fostering beneficial microbiota[5][7]. Disruption or dysfunction can lead to increased transepidermal water loss (TEWL), dryness, inflammation (as seen in eczema), increased susceptibility to infection or allergen penetration. Because it is not a discrete molecular target such as an enzyme or receptor but rather an anatomical-functional concept describing tissue organization at the microscopic level,[1][2] "skin moisture barrier" should not be considered a canonical therapeutic target. Instead therapies aim to support its function through topical agents that restore lipids or attract/retain moisture. > "The stratum corneum forms a 'brick-and-mortar' structure... The bricks are flattened dead cells called corneocytes; the mortar consists mainly of lipids... Together they create an effective permeability barrier against both water loss from within and entry by external substances."[1][2] In summary: **"Skin moisture barrier"** describes an essential physiological property conferred by the stratum corneum's unique architecture—not a specific molecule/receptor—and thus does not fit standard drug-target classification schemes.

Other names

Skin barrierMoisture barrierEpidermal barrierPermeability barrier

Restoration or enhancement of lipid matrix and natural moisturizing factors