Will Vitamin C Help Prevent Colds?

Reviewer's conclusions: Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds. There appears to be a modest benefit in reducing duration of cold symptoms from ingestion of relatively high doses of vitamin C.

How much vitamin C should I take to prevent a cold?

So there's some evidence of the benefit of vitamin C supplements (500 mg to 2000 mg per day) for the prevention of colds in physically active people.

Does vitamin C make a cold worse?

Although vitamin C supplements have no effect on the risk of catching a cold, they appear to reduce its severity and duration.