Ascorbyl palmitate is a fat soluble vitamin C ester. An ester is simply a compound formed by the combination of an organic acid and an alcohol – in this case it is ascorbic acid and palmitic acid (a fat – which is composed of fatty acids and glycerol - an alcohol). Therefore, ascorbyl palmitate is formed by the esterification of ascorbic acid with palmitic acid to form vitamin C ester. Ascorbyl palmitate is an amphipathic molecule, meaning one end is water-soluble and the other end is fat-soluble. This dual solubility allows it to be incorporated into cell membranes. When incorporated into the cell membranes of human red blood cells, ascorbyl palmitate has been found to protect them from oxidative damage and to protect alpha-tocopherol (a fat-soluble antioxidant) from oxidation by free radicals. Basically, the fat-soluble aspect of ascorbyl palmitate extends vitamin C free radical protection into the fat parts of the body. However, the protective effects of ascorbyl palmitate on cell membranes have only been demonstrated in the test tube (in vitro). Taking ascorbyl palmitate orally may not result in any significant incorporation into cell membranes because most of it appears to be hydrolyzed (broken apart into palmitate and ascorbic acid) in the human digestive tract before it is absorbed. The ascorbic acid released by the hydrolysis of ascorbyl palmitate appears to be as bioavailable as ascorbic acid alone. The presence of ascorbyl palmitate in oral supplements contributes to the ascorbic acid content of the supplement and probably helps protect fat-soluble antioxidants in the supplement. This is also true for food products. Ascorbyl palmitate is used to increase the shelf life of vegetable oils and potato chips. The role of vitamin C in promoting collagen synthesis and its antioxidant properties have generated interest in its use on the skin. Ascorbyl palmitate is frequently used in topical preparations because it is more stable than some aqueous (water-soluble) forms of vitamin C. It is also suggested that this form of vitamin C is better able to penetrate the skin and the thin membrane of cells (due to its dual solubility), which can then go on to help produce collagen and elastin.