text: Vitamin C is a water-soluble nutrient essential for life, used by the human body for many purposes. It is one of a number of such key nutrients called vitamins.\n\nTo the best of scientific knowledge, all animals and plants synthesize their own vitamin C, except for humans and a small number of other animals, including, apes, guinea pigs, the red-vented bulbul, a fruit-eating bat and a species of trout. This has led a minority of scientists, most notably Linus Pauling to conclude that failure to produce the chemical by an animal species is a genetic defect and to hypothesize that if it were replaced in humans to the level found in animals better health would result.\n\nVitamin C was first isolated in 1928, and in 1932 it was proved to be the agent which prevents scurvy. In 1937 Albert Szent-Györgyi was awarded the Nobel Prize for this feat.\n\nVitamin C is a weak acid, called ascorbic acid or ascorbate (an L-enantiomer of ascorbic acid; an L-enantiomer is simply one of two mirror image forms of the same chemical molecular structure, see optical isomers). The active part of the substance is the ascorbate ion, which can express itself as either an acid or a salt of ascorbate that is neutral or slightly basic. Commercial vitamin C is often a mix of ascorbic acid, sodium ascorbate and/or other ascorbates. Some supplements contain in part the D-enantiomer, which is useless but harmless. See the ascorbic acid article for a full description of the molecule's chemical properties.\n\nFunctions in the body\n\nAs a participant in hydroxylation, vitamin C is needed for the production of collagen in the connective tissue. These fibers are ubiquitous throughout the body; providing firm but flexible structure. Some tissues have a greater percentage of collagen, especially: skin, mucous membranes, teeth and bones. \n\nVitamin C is required for synthesis of dopamine, noradrenaline and adrenaline in the nervous system or in the adrenal glands. \n\nVitamin C is also needed to synthesize carnitine, important in the transfer of energy to the cell mitochondria. \n\nIt is a strong antioxidant. \n\nThe tissues with greatest percentage of vitamin C — over 100 times the level in blood plasma — are the adrenal glands, pituitary, thymus, corpus luteum, and retina. \nThe brain, spleen, lung, testicle, lymph nodes, liver, thyroid, small intestinal mucosa, leukocytes, pancreas, kidney and salivary glands usually have 10 to 50 times the concentration present in plasma. \n\nNo bodily organ stores ascorbate as a primary function, and so the body soon depletes itself of ascorbate if fresh supplies do not continue to arrive through the digestive system, eventually leading to death if unresolved.