The easiest way to understand and to communicate the structure of skin is to view the stratum corneum as a brick and mortar wall. The ‘bricks’ are corneocytes while the ‘mortar’ are the lipids. Corneocytes are connected by proteins called desmosomes. Inside each corneocyte are Natural Moisturising Factors (NMFs) that draw moisture into the cell.
The stratum corneum regulates a natural rate of water loss in the skin, a process called Transepidermal Water Loss (TEWL). Normal healthy moisturised skin loses about 80-100 grams of water into the atmosphere each day. The TEWL process is affected by the integrity of the lipid structure and the Natural Moisturising Factor. For healthy moisturised skin, these elements regulate the rate of TEWL and help maintain the proper moisture levels within the stratum corneum.
