Does Vitamin C Prevent Colds?
No, but it might shorten them slightly. 29 trials involving 11,306 people show vitamin C doesn't prevent colds in the general population. Once sick, it may reduce duration by 8% (about half a day). Not the miracle Linus Pauling promised.
The Numbers
How much scientific truth is there?
How much is just marketing?
Marketing vs Reality
What Marketing Says
- "Immune system support"
- "Take at first sign of cold"
- "Mega-dose for mega protection"
- "Essential for fighting illness"
What Science Says
- Cochrane review (2013): No prevention benefit in general population.
- Regular supplementation: Colds 8% shorter (about 8 hours on a 4-day cold).
- Taking vitamin C after symptoms start: No benefit.
- Exception: Marathon runners and extreme exercisers see 50% reduction in colds.
Reality Check
Linus Pauling (Nobel laureate) claimed vitamin C megadoses prevented colds in the 1970s. He was wrong. Decades of research proved it. But the myth persists because it feels intuitive. When sick, we want to "boost" something. Vitamin C is the something.
What To Do Instead
- 1Get vitamin C from food. Citrus, peppers, broccoli have plenty.
- 2Don't mega-dose when sick. It won't help.
- 3Focus on sleep and hydration when you have a cold.
- 4If you want insurance, 200mg daily is the studied dose. Not 2000mg.
The Exception
Athletes training heavily may benefit from regular vitamin C supplementation. Extreme physical stress appears to be a special case where vitamin C helps prevent illness.
The Bottom Line
Eat your oranges, but don't expect miracles. Vitamin C is a vitamin, not a cold cure.
Related Supplements
But Wait...
Doesn't work. Studies show taking vitamin C after symptoms start has no effect.
More Myths to Bust
About this information: Our recommendations draw from peer-reviewed clinical trials, systematic reviews, and the same medical databases your doctor uses. These statements have not been evaluated by the FDA. Supplements are not intended to diagnose, treat, cure, or prevent any disease.
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