Physical barrier formation on the skin surface

The **physical barrier formation on the skin surface** is a coordinated multi-step process, primarily achieved by the stratum corneum, the outermost layer of the epidermis[1][2][4][6][9]. This barrier consists of "bricks" (flattened, cornified keratinocytes known as corneocytes) and "mortar" (extracellular lipid matrix, including ceramides, cholesterol, and fatty acids)[1][2]. Key molecular components include filaggrin, involucrin, loricrin, desmosomal proteins, and enzymes responsible for cross-linking proteins and synthesizing lipids[1][7]. The barrier restricts transepidermal water loss, blocks pathogen entry, and minimizes chemical penetration, essential for overall health and prevention of skin disease[1][2][4][6][9]. Barrier dysfunction due to genetic (e.g., filaggrin mutations) or environmental factors leads to dry skin, increased sensitivity, and inflammation,[7] and is a central feature of disorders such as atopic dermatitis and ichthyosis[7]. Therapeutic approaches aim to restore or enhance this barrier, often by supplementing key lipids or proteins, reducing protease activity, or hydrating the stratum corneum[1][4][7].

Other names

Physical skin barrierStratum corneum barrierEpidermal barrierSkin barrier

Restoration or enhancement of skin barrier integrity (for barrier-improving topical drugs) Modulation of lipid production Promotion of protein cross-linking in the stratum corneum