Like Urea, Lactate (the salt of Lactic Acid) is also a “natural moisturising factor” (NMF), and is produced naturally by the skin. Lactate absorbs and retains moisture within the stratum corneum, or upper layer of the skin, and therefore plays a vital role in maintaining the skin’s physical properties. Low levels of Lactate within the stratum corneum are known to be associated with dry skin.