Vitamin C

L-ascorbic acid, L-dehydroascorbic acid

Vitamin C (L-ascorbic acid) is a water-soluble carbohydrate that occupies a singular position in human biochemistry. Humans, along with other primates and guinea pigs, have lost the ability to synthesize vitamin C due to mutations in the GLO gene, making dietary intake absolutely essential. Its most significant role is as a cofactor for prolyl and lysyl hydroxylase enzymes that create collagen's triple-helix structure. As an antioxidant, it scavenges reactive oxygen species and regenerates vitamin E.