Moisturizing agents are ingredients that are specially designed
with functionality to restore or increase water to the external
layer of the skin (stratum corneum). By restoring moisture it
will make the skin softer and more pliable. Modes of
effectiveness to increase the skin's hydration (water content) include humectancy and occlusivity (reducing evaporation). Naturally occurring skin lipids and sterols, as well as artificial or natural oils, humectants, emollients, lubricants, etc., may be part of the composition of commercial skin moisturizers.