Naturally occurring skin lipids (fats) that are major structural components of the skin’s outer structure. Skin as a barrier system inhibits water movement via its extracellular matrix, which has a unique composition of 50% ceramides, 25% cholesterol, and 15% free fatty acids (Sources: Journal of Lipid Research, September 2007; Journal of Investigative Dermatology, November 2001, pages 1126–1136; and Experimental Dermatology, October 2005, pages 719–726). Ceramides are necessary for the skin’s water-retention capacity as well as for cell regulation. Adding ceramides to skin-care products can help to restore the skin’s barrier system (Sources: American Journal of Clinical Dermatology, June 2005, pages 215–223; Journal of Dermatological Science, September 2006, pages 159–169; Skin Pharmacology and Applied Skin Physiology, September–October 2001, pages 261–271; and Cutis, December 2005, Supplemental, pages 7–12).