Stratum corneum water content regulation

Stratum corneum water content regulation" refers to the physiological processes and structural features that control the amount of water retained within the stratum corneum, which is the outermost layer of human skin. The stratum corneum consists primarily of **corneocytes** embedded in an **intercellular lipid matrix** composed mainly of ceramides, free fatty acids, and cholesterol[1][3]. Water is stored mainly within the corneocytes but also interacts with lamellar structures formed by intercellular lipids. Two main types of lamellar structures exist—short lamellar (S-La) and long lamellar (L-La)—with S-La containing hydrophilic regions that can hold small amounts of water[2][3]. The **water content in healthy human stratum corneum is typically regulated at 20–30% by weight**, which stabilizes these lipid structures and maintains optimal barrier function[1]. Changes in hydration affect both lipid organization and permeability; for example, drying increases lipid order and improves barrier properties but reduces flexibility[4]. Conversely, increased hydration disrupts lipid packing and can enhance penetration by drug carriers or other substances[2][3]. This entry does not correspond to a single molecule or receptor but rather describes an emergent property resulting from interactions among proteins (such as keratins), lipids, natural moisturizing factors, and environmental influences like humidity. Therefore, it should not be considered a canonical therapeutic target such as an enzyme or receptor. In summary: > "Stratum corneum water content regulation" describes how various structural elements—primarily intercellular lipids and keratin-rich cells—work together to maintain appropriate hydration levels in the outermost skin layer. This process underpins normal skin barrier function but does not represent a discrete molecular target suitable for direct pharmacological intervention[1][2][3][4]. Because this term refers to a complex physiological mechanism rather than an individual molecule or receptor: **is_target:** false **is_incorrect:** true

Not applicable (not a discrete molecular target; rather, it is a physiological process involving multiple components)