Your skin’s ability to prevent evaporative moisture loss, i.e. transepidermal water loss, is dependent upon the integrity of the fatty acid “mortar” between your skin cells. For the mortar to maintain a water seal it must remain acidic.
Normal skin is slightly acidic (pH 5.6-5.8), and this acidity maintains the fatty acid mortar barrier. Almost everything in the environment that contacts our skin is basic: dirt, common bath soaps, dish detergents, makeup, some lotions and moisturizers. As a result, the water barrier is constantly under deterioration. Ever wonder why soaking in a bubble bath makes you itch?
Maintenance of the water barrier can be achieved in two ways. First and foremost, use a cleanser that is slightly acidic. Second, add a toner to your skin care program. Toners acidify the skin to counter environmental alkaline exposure.
Maintaining healthy skin is chemistry too!