Vitamin C (ascorbic acid) is a water-soluble nutrient with numerous physiological functions, and it is essential to human health. While most mammals are able to synthesize vitamin C as needed, humans do not have this capability and must obtain it exogenously. Vitamin C is the primary aqueous phase antioxidant. It is necessary for the development and maintenance of collagen, cartilage, and blood vessels; critical for the absorption of iron; needed for synthesis of
carnitine, neurotransmitters, and as a cofactor for metabolic enzymes; and significant for its role in immune system function.