Going Beyond Ceramides in Moisturizers: The Role of Natural Moisturizing Factors

Xerosis is experienced by almost everyone at some time in their lives and the foundation of management of dry skin (both consumer- and healthcare professional--directed) rests on the use of moisturizers. Given the wide range of available moisturizers, counseling patients about selecting the optimum moisturizer for their individual situation relies on knowledge of ingredients and formulations. Traditionally, the main focus for many moisturizers centered on the core functional and structural role of ceramides within the epidermal barrier. However, while a key aspect of transepidermal water loss and other skin barrier functions, components other than ceramides are equally essential in increasing moisturization. The skin's natural moisturizing factors (NMFs) are a complex mixture of water-attracting compounds such as amino acids, urea, lactate, pyrrolidone carboxylic acid (PCA), and electrolytes which play a fundamental role in preserving physiologic function by regulating the water content of the stratum corneum. By facilitating water retention, NMFs contribute significantly to the suppleness, elasticity, normal desquamation, and overall integrity of the skin barrier. Incorporation of NMFs into moisturizers addresses critical deficiencies in the skin's moisture balance that exist in xerotic and atopic skin, and in many skin disorders, mitigating signs and symptoms associated with xerosis and promoting optimal skin health. The biochemical composition of NMFs and the intricate interplay with epidermal homeostasis translate to a central role in moisturizers used for prophylactic and therapeutic management of various dry skin conditions, beyond ceramides alone.