Vitamin C
Ascorbic acid, a powerful water-soluble antioxidant essential for immune function, collagen synthesis, iron absorption, and protection against oxidative stress.
Marketing vs Evidence
What brands claim
"Boosts immunity, prevents colds, fights oxidative stress" — one of the most over-marketed vitamins.
What the research shows
Reduces cold duration by roughly 8% in adults — a real but modest effect. Does not prevent colds in the general population. Megadoses above ~500 mg provide little additional benefit once tissues are saturated.
What it’s good for
Vitamin C supports immune function by enhancing neutrophil chemotaxis, phagocytosis, and reactive oxygen species generation. It also supports epithelial barrier function, increases natural killer cell activity, and modulates T-cell maturation.
Dose: 500–1000 mg
Vitamin C is required for collagen synthesis (hydroxylation of proline and lysine), essential for wound healing and tissue repair. It also enhances immune cell function, reduces oxidative stress from injury, and supports iron absorption for tissue oxygenation.
Dose: 500–2000 mg