The Study
Vitamin C for preventing and treating the common cold.
This study looks at many smaller studies about vitamin C and colds. It can suggest that vitamin C might help with colds, but because we only have a summary and not all the details, we can't be totally sure.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
This study looked at many other studies to see if vitamin C stops or shortens colds.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 533 / 100
Quality score
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Small benefits only for specific groups; not helpful for treating colds once you have them.
- 2For most people, vitamin C doesn't prevent colds.
- 3For people under high stress, it might cut colds in half.
- 4It shortens colds a little if taken before getting sick, but doesn't help after symptoms start.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Cochrane database of systematic reviews
Year
2004
Authors
Hemilä Harri, Chalker Elizabeth, Treacy Barbara, Douglas Bob, Cochrane
Related Content
Claims (5)
This claim says that taking lots of vitamin C, echinacea, garlic, or vitamin D doesn't actually help you get better from a cold, according to real studies done on people.
Taking vitamin C after you already have a cold doesn't really help you get better faster or feel less sick, according to several big studies.
Taking vitamin C pills every day doesn't really help prevent colds for most people, according to studies with thousands of participants.
Taking vitamin C supplements might cut your chances of getting a cold in half if you're under a lot of physical stress, like running marathons, skiing, or doing tough military training in cold weather.
Taking vitamin C regularly might help you get over a cold a little faster—about 8% quicker for adults and 13% for kids, according to a big study.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.