Stratum corneum hydration (SCH) (SCH)

Stratum corneum hydration (SCH) refers to the water content maintained within the outermost layer of the epidermis, which is vital for maintaining the skin's physical properties and biological functions [1]. While the user's term mentions the extracellular matrix, water in the stratum corneum is primarily sequestered within corneocytes by Natural Moisturizing Factors (NMFs), though small amounts exist in the intercellular lipid lamellae [2]. This hydration is essential for the activity of enzymes like kallikreins, which regulate desquamation, and for maintaining the flexibility of the protein-lipid structure [3]. Reduced hydration leads to clinical conditions such as xerosis and atopic dermatitis, characterized by a compromised barrier and increased transepidermal water loss (TEWL) [4]. Therapeutic strategies do not target a single molecule but rather modulate hydration using humectants to draw water in and occlusives to prevent its escape [1,2]. Consequently, SCH is a key physiological endpoint in dermatological research and product development rather than a specific molecular target like a receptor or enzyme [3,4].

Other names

Extracellular matrix water content in stratum corneumSkin hydrationStratum corneum water contentCorneal layer moistureTransepidermal water retention

Therapeutic agents increase hydration through three primary mechanisms: humectancy (binding water via hygroscopic molecules), occlusion (forming a physical barrier to prevent evaporation), and emolliency (filling intercellular spaces to restore barrier integrity).