Vitamin C vs zinc — which is better for colds?

For the classic "take this when you feel a cold coming on" use case, zinc has the better evidence. An updated Cochrane review found zinc reduces cold duration when started within 24 hours of symptom onset — a specific, actionable, and consistently-replicated finding. Vitamin C's evidence is weaker than its reputation: a well-known Cochrane review found regular supplementation does not reduce how often you catch a cold in the general population, only modestly shortening the duration once you have one — much less exciting than the popular "vitamin C prevents colds" belief. Zinc also has a separate, unrelated evidence strength vitamin C doesn't share: the landmark AREDS trial found high-dose zinc combined with antioxidants slows progression of age-related macular degeneration. If cold relief is the goal, zinc — timed early — currently has the stronger, more specific case.