The skin barrier is the protective function of the skin’s outer surface. The stratum corneum—the outermost layer of the epidermis—helps limit water loss and protects the body from outside substances.
The stratum corneum
The stratum corneum contains flattened cells called corneocytes set in lipids. “Bricks and mortar” is a shorthand for this arrangement.
Natural moisturizing factor (NMF) is a mixture inside corneocytes that binds water.
Acid mantle
The acid mantle is the skin’s naturally acidic surface environment. Its measured pH varies by body site and conditions; skin pH is associated with barrier function and resident microbes. [1,2]
Related measure: TEWL
Transepidermal water loss (TEWL) is water moving through the skin and evaporating from its surface. It is one measure of barrier function; hydration describes water in the outer skin.
Related entry: Hydration & moisturizing.
