Understand the biological terms and physiological processes that define skin and scalp barrier functions.
The thin, slightly acidic film (pH 4.5 - 5.5) on the surface of the skin. It is made of lipids, amino acids, and sweat, and acts as a barrier to block harmful bacteria and virus particles.
Dead squamous skin cells that form the cellular 'bricks' of the stratum corneum. They are packed with keratin proteins and surrounded by lipids to shield the skin.
An androgen hormone byproduct. When it binds to hair follicle receptors, it shrinks the follicles, shortening the hair's growth phase and leading to thinning.
A genus of lipophilic yeast flora naturally found on the skin. An overgrowth of Malassezia feeding on excess sebum can lead to scalp scaling, dandruff, and seborrheic dermatitis.
The biochemical process by which epidermal melanocytes produce melanin pigment granules. This process is triggered by UV radiation or inflammatory hormones.
The biological process of building new collagen fibers. This process is stimulated by active ingredients (like Vitamin C or Retinol) to support skin firmness and elasticity.
The passive evaporation of water from inside the body through the skin barrier into the surrounding air. High TEWL is a primary sign of a compromised skin barrier.