Moisturizing Agent

Several categories of ingredients make it possible to maintain hydration:

• Humectant agents which retain water thanks to their hygroscopic capability (having strong affinity for water). Among humectants: Urea, Amino-Acids, Sodium Lactate, Glycerol or Glycerin, Propylene Glycol, PEG (Polyethyleneglycol), and Sorbitol.
• Film-forming agents, substances which together with water form semi-permeable hydrogels, less effective in time than  occlusive agents, but more acceptable agents because they allow the skin to 'breathe'. Among the film forming agents: Collagen, Elastin, DNA, Pectin, Gelatine, Chitosan, the Glycosaminoglycans (like Hyaluronic Acid).
• Occlusive agents which form an impermeable film on the surface of the skin. Among the occlusive agents: Petroleum Jelly, Paraffin, Vaseline Oil, Sweet Almond Oil (Prunus Amygdalus Dulcis Oil), Wheat germ Oil, Shea Butter (Butyrospermum Parkii Butter), Beeswax (Cera Alba).
• Lyotropic agents which can retain water thanks to their amphiphilic character: these molecules have at the same time an absorbent part (which has affinity for water) and a hydrophobic part (which does not have affinity for water). Among the lyotropic agents: Lanolin and its derivatives, Ceramides, AGE (essential fatty-acids).