The only functional role of vitamin C categorically established is its ability to prevent and/or cure scurvy. In this role, however, it affects to some extent every body function. For example, normal development of cartilage, bone, and dentine depends on an adequate supply of vitamin C. In addition, the basement membrane lining the capillaries, the “intracellular cement” holding together the endothelial cells, and the scar tissue responsible for wound healing all require the presence of vitamin C for their formation and maintenance. Ascorbic acid is an antioxidant, cofactor of hydroxylating enzymes involved in synthesis of collagen, carnitine, norepinephrine. Horses can produce endogenous vitamin C, there is no evidence supplementation is needed.