Vitamin C 500 mg

Ascorbic acid (Vitamin C) is a water-soluble electron donor that participates as a cofactor in at least 15 enzymatic reactions, most critically the prolyl and lysyl hydroxylases that hydroxylate procollagen chains — a mandatory step for triple-helix formation and collagen fibril stability. As the primary aqueous-phase antioxidant in human plasma, ascorbate neutralises superoxide, hydroxyl radicals, and singlet oxygen, and regenerates lipophilic Vitamin E from its radical form. Meta-analyses of randomised trials confirm that Vitamin C supplementation reduces cold duration by 8% in adults and 14% in children. The 500 mg dose represents the optimal bioavailable range, as absorption efficiency diminishes significantly above 1 g.