Keratin fiber and intercellular lipid of the stratum corneum

Keratin fibers and intercellular lipids of the stratum corneum represent the main structural components of the outermost layer of the skin, which acts as a protective barrier. Keratin fibers are organized into a dense network of intermediate filaments within corneocytes, providing mechanical strength and contributing to the skin's elasticity and water-holding properties[1][2][3][4][5]. Intercellular lipids—primarily ceramides, cholesterol, and free fatty acids—are arranged between corneocytes, forming lamellar structures essential for water barrier function and cohesion of the stratum corneum[2][3][4]. This combined architecture prevents transepidermal water loss and protects against environmental insults and pathogens. Disruption in either component is associated with impaired barrier function and various skin diseases. As they are not single molecular targets but complexes of structural proteins and lipids, these entities do not fit conventional definitions of drug targets (such as receptors or enzymes), though they are the focus of many dermatological formulations aiming to repair or protect the barrier[2][4][5].

Other names

Stratum corneum keratinCorneocyte keratin filamentsStratum corneum intercellular lipid

Restoration or augmentation of lipid barrier (for emollients and ceramides); Softening and hydration of keratin (keratolytics); Modulation of corneocyte cohesion/desquamation (topical formulations)