Conclusion: The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise. Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it m
PubMed 23440782 ↗Vitamin C
People mainly take Vitamin C for energy, skin & hair, immunity. Based on 458 first-hand reports and 738 meta-analyses & systematic reviews in the medical literature. Ranked #146 of 1,974 overall.
Of reports that state an outcome, 73% are positive.
What Vitamin C does, according to users
Of the people who reported each effect, the share who said it got better.
What the research says
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
3+ meta-analyses or systematic reviews and 10+ randomized controlled trials in humans. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: This study suggests the potential ability of vitamin C and E in alleviating pain symptoms experienced by individuals with endometriosis.
PubMed 38820340 ↗Conclusion: Deficiencies or imbalances in specific vitamins and minerals, especially vitamin B, vitamin D, Fe, Se, and Zn are involved in the pathogenesis of AGA and may represent modifiable risk factors for the treatment and prevention of this condition.
PubMed 39440586 ↗Conclusion: This guideline should enable addressing suboptimal and deficient status of a bundle of MNs in at-risk diseases. In particular, it offers practical advice on MN provision and monitoring during nutritional support.
PubMed 35365361 ↗Dosage people report
As stated by users — not a recommendation. Follow the label or your doctor.
Reported side effects
How often each side effect came up across all reports.
What users say
Verbatim quotes, shortened only — each links to the original discussion.
“2000Vit.C”
“For me vitamin C did the trick. I used to have 4-5 flus a year but now usually none. I take 500mg a day.”
“I take red yeast rice, coq10, vitamin d, vitamin c, a probiotic and a multivitamin.”
“Vitamin C”
“Eat some fruit, no need to supplement vitamin C.”
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Other options for energy
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 2, 2026. How we rate