One of the primary elements in keeping skin healthy is making sure the structure of the epidermis (outer layer of skin) is intact. The components that do this are often called Natural Moisturizing Factors (NMF) or ingredients that mimic the structure and function of healthy skin. While the oil and fat components of the skin prevent evaporation of moisture and provide lubrication to the skin surface, it is the intercellular matrix, along with the skin’s lipid content, that gives the skin its texture and feels.
The role of the NMF is to maintain adequate skin hydration. Adequate hydration serves three major functions: (1) it maintains the elasticity of the skin, protecting it from damage (2) it allows hydrolytic enzymes to function in the process of desquamation, and (3) it contributes to the optimum stratum corneum barrier function. Traditionally, the stratum corneum is thought of as nonviable tissue. While this is true, the stratum corneum is a dynamic structure in which numerous enzymes still function, and these enzymes require a certain amount of water to perform. NMF water-binding provides much of this necessary water. Many of these enzymes are involved in the process of desquamation, breaking the various bonds and forces holding the corneocytes together in the most superficial layers of the skin. Research shows the activity of these desquamatory enzymes is affected by water levels within the tissue.
Reduction or the lack of NMF has been correlated with various stratum corneum abnormalities that manifest clinically as areas of dry skin with scaling, flaking, or even fissuring and cracking. These conditions include psoriasis, ichthyosis Vulgaris, and xerosis It has been shown that the reduction in NMF levels is a normal feature, while in psoriatic skin and ichthyosis, the NMF is essentially absent.