Vitamin C

Vitamin C has multiple mechanisms:

• Antioxidant: Directly scavenges free radicals and reactive oxygen species. Regenerates vitamin E.
• Collagen Synthesis: Cofactor for prolyl and lysyl hydroxylases, enzymes essential for collagen cross-linking and stability.
• Carnitine Synthesis: Required for producing carnitine, which transports fatty acids into mitochondria.
• Neurotransmitter Synthesis: Cofactor for dopamine β-hydroxylase (converts dopamine to norepinephrine).
• Iron Absorption: Reduces ferric iron (Fe³⁺) to ferrous iron (Fe²⁺) for better intestinal absorption.
• Immune Support: Enhances various immune cell functions including neutrophil function and lymphocyte proliferation.

Key Benefits

• Immune support: Shortening common cold duration modestly and supporting white blood cell function.
• Collagen and skin health: Essential for collagen synthesis, wound healing, and skin integrity.
• Antioxidant protection: Regenerating vitamin E and protecting cells from oxidative stress.
• Iron absorption: Enhancing non-heme iron uptake, especially important in iron deficiency.

Deficiency leads to scurvy with bleeding gums, poor wound healing, and fatigue.

How Vitamin C is Used

• Daily intake: Meeting the RDA (75–90 mg) through diet, with higher intakes (e.g., 200–500 mg/day) common for additional antioxidant and immune support.
• Immune support: 500–1,000 mg/day in divided doses during cold season.
• Clinical contexts: Higher oral or IV doses are sometimes used in hospital settings under medical supervision.

GI tolerance is the practical upper limit for oral dosing; splitting doses improves absorption and reduces side effects.