Vitamin C
An essential antioxidant. Contrary to popular belief, it does not prevent colds in the general population — but it may shorten them slightly.
What the science says
- Cold prevention Limited evidence
A Cochrane review with over 11,000 participants: regular supplementation does NOT reduce cold incidence in the general population. Exception: people under extreme physical stress (marathon runners, soldiers), whose risk was cut in half.
- Shorter cold duration Moderate evidence
Regular use (not use started after symptoms appear) modestly reduced cold duration: ~8% in adults and ~14% in children.
Dosage & safety
Studied doseThe daily requirement (~90 mg) is easily met through diet. Studies use 200 mg to 1 g/day for the effect on cold duration.
SafetyVery safe; excess is excreted in urine. Doses above 2 g/day can cause diarrhea and increase kidney stone risk in predisposed people.
Scientific references
Where to buy
California Gold Nutrition, Gold C®, USP Grade Vitamin C, 1,000 mg, 60 Veggie Capsules
View on iHerbReferral link — this site may earn a commission on purchases.
Related in Immunity
- Zinc Moderate evidence
- Elderberry Limited evidence
- L-Lysine Limited evidence
- Echinacea Limited evidence
- Andrographis Moderate evidence
- Astragalus Limited evidence