The Relation of pH and Skin Cleansing.

Abstract

Several epidermal barrier functions, like skin barrier regeneration and antimicrobial response, are related to the acidic nature of the skin surface pH (ss-pH). However, the epidermal acidification is known to be fragile and it is commonly accepted that cosmetic products, especially soaps and skin cleansing products, can induce significant changes in ss-pH. As a consequence, epidermal barrier function and skin microflora are affected negatively. ss-pH even increases after a single washing procedure or after rinsing the skin with water alone. The skin pH recovery needs time up to several hours before it can reach the physiological level. For cosmetic-relevant skin conditions, skin disorders and specific consumer groups, maintaining of the acidic ss-pH is beneficial for epidermal physiology and cutaneous microflora. In this context, cleansing and skin care products with a pH level of 4.0-5.0 may be helpful. In addition, combining the acidic product pH level with the ideal mix of surfactants, thereby enhancing product compatibility and minimizing skin irritation and intolerance, is a major challenge for the future. Beyond innovative cleansing technology, further multifaceted cosmetic research is a prerequisite to get deeper knowledge on the interrelation of product pH level, surfactant composition and corneobiology.