Question 1

Does vitamin C actually prevent colds?

Accepted Answer

No. The Cochrane Collaboration's analysis of 29 randomized controlled trials found that regular vitamin C supplementation did not reduce cold incidence in the general population. Taking vitamin C after symptoms begin, the most common use, showed no consistent benefit at all.

Question 2

Why do people still take vitamin C for colds if it doesn't work?

Accepted Answer

The belief persists because Linus Pauling, a prestigious two-time Nobel laureate, promoted it in his 1970 bestseller. His authority created a cultural halo around the claim that the clinical evidence never supported. Commercial interests in the supplement industry have further reinforced this association for decades.

Question 3

Is there any group where vitamin C supplements actually help with colds?

Accepted Answer

Yes, among extreme athletes like marathon runners and ultramarathoners undergoing sustained physical stress, vitamin C supplementation reduced cold incidence by about half. However, this narrow exception does not apply to ordinary people experiencing typical cold symptoms.

evidence-based-medicine

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The Long Half-Life of a Nobel Laureate's Mistake