Intercellular substances (which I often refer to as ingredients that mimic the structure of skin) should be the backbone of every moisturizer. In fact, moisturizers are not about giving skin moisture or keeping water in skin. All current research is about moisturizers keeping the outer layer of skin resilient and healthy, and that has little to do with water content. But it does have everything to do with giving skin the substances that keep skin cells intact so they can defend themselves against the environment, feel soft and supple, and maintain a reliable protective balance. Ingredients such as ceramides, cholesterol, fatty acids (linoleic acid, triglycerides, glycerin, phospholipids, lecithin), and glycosaminoglycans (hyaluronic acid, sodium PCA) are essential for helping skin to function normally, as it once did before sun damage and age got the better of us. (Sources: Clinical and Geriatric Medicine, February 2002, pages 103-120; Progress in Lipid Research, January 2003, pages 1-36; Journal of the European Academy of Dermatology & Venereology, November 2002, pages 587-594; Contact Dermatitis, June 2002, pages 331-338; Journal of Investigative Dermatology, May 1996, pages 1096-1101; British Journal of Dermatology, November 1995, pages 679-685; Skin Pharmacology and Physiology, September-October 2004, pages 207-213; Free Radical Research, April 2002, pages 471–477; and Journal of Lipid Research, May 2002, pages 794–804.)