Keratin proteins and water molecules in the stratum corneum (SC Keratin-Water Complex)

The stratum corneum (SC) is the outermost layer of the epidermis, serving as the body's primary physical barrier against environmental insults and water loss (Source: StatPearls, Physiology, Skin). It consists of corneocytes filled with keratin intermediate filaments (primarily Keratin 1 and Keratin 10) embedded in a lipid-rich matrix (Source: UniProt). The interaction between these keratin proteins and water molecules is fundamental to skin health; water acts as a plasticizer that maintains the flexibility of the keratin matrix and is essential for the activity of hydrolytic enzymes that regulate desquamation (Source: Journal of Investigative Dermatology). When the hydration of this complex falls below a critical threshold, the skin becomes brittle, leading to xerosis, scaling, and impaired barrier function (Source: Mayo Clinic). Therapeutic agents target this system in two primary ways: humectants like urea and glycerin chemically bind water to the keratin structure to restore hydration, while keratolytics like salicylic acid soften the keratin to facilitate the removal of excess scales in hyperkeratotic conditions (Source: American Academy of Dermatology). Maintaining the integrity of the keratin-water complex is a cornerstone of treatment for chronic inflammatory skin diseases such as atopic dermatitis and psoriasis (Source: Journal of Clinical and Aesthetic Dermatology).

Other names

Stratum corneum hydration complexCorneocyte keratin matrixKeratin-water systemSkin hydration barrier

Humectants increase hydration by binding water molecules to keratin filaments via hydrogen bonding, while keratolytics disrupt keratin-keratin interactions to promote the shedding of corneocytes.