Multivitamins and Longevity: What the Trials Show
What randomized trials and large cohort studies show about daily multivitamins, cancer, heart disease, memory and death in older adults, and what remains unproven.
Content last updated . This page has not been medically reviewed.
The US Preventive Services Task Force (USPSTF) concluded in 2022 that evidence was insufficient to judge the balance of benefits and harms of multivitamins for preventing cardiovascular disease or cancer. [1]
The main trials
| Study | Who | Result |
|---|---|---|
| Physicians' Health Study II, heart | 14,641 male US physicians aged 50+, median follow-up 11.2 years | No effect on major cardiovascular events (hazard ratio 1.01); total death 0.94, not statistically significant [2] |
| Physicians' Health Study II, cancer | Same men | Small reduction in total cancer (hazard ratio 0.92, 95% CI 0.86 to 0.998); no effect on prostate or colorectal cancer [3] |
| COSMOS-Mind | 2,262 adults, mean age 73, 3 years | Better global cognition scores (0.07 standard-deviation units) [4] |
| COSMOS-Clinic and combined analysis | Substudies of 21,442 US adults aged 60+ | Small gains in global cognition and episodic memory [5] |
| COSMOS-Mind, impairment | Same trial | No significant change in mild cognitive impairment or dementia; few cases, so low power [6] |
Observational data: users versus non-users
In a pooled analysis of three large US cohorts (390,124 adults, up to 27 years), daily multivitamin users did not have lower all-cause mortality; the hazard ratio was 1.04 early in follow-up. [7] Observational studies cannot prove cause and effect, but this one tried to account for healthy habits and for people who started vitamins because of illness.Bottom line
Label: mixed overall, insufficient evidence for preventing heart disease and cancer, promising but limited for cognition. No source we read shows that a multivitamin extends human lifespan.See also Longevity interventions: what human evidence exists and Supplements for healthy aging.
Frequently asked questions
Do multivitamins help you live longer?
Not in the evidence we read. The Physicians' Health Study II found no significant effect on total death, and a three-cohort analysis found no lower death risk among users. [2][7]
Did the COSMOS trial prove multivitamins protect memory?
No. It found small improvements in cognitive test scores, but not a significant reduction in mild cognitive impairment or dementia. Confirmation is needed. [4][6]
Do multivitamins prevent cancer?
One trial of male physicians found a small reduction in total cancer, but none for prostate or colorectal cancer. The USPSTF still found the evidence insufficient. [3][1]
Is a multivitamin safe to take every day?
It depends on the product and the person. Ask a doctor or pharmacist, especially if you take medicines. [8]
Is this medical advice?
No. This page describes research and does not tell anyone to start, stop or change a supplement or medicine.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read these results
- Cancer signal. The result was close to the line of statistical significance, and the trial enrolled male physicians, so it may not apply to women or to other groups. [3]
- Memory signal. The effect sizes were small. The COSMOS-Mind authors said work is needed in a more diverse group, because 89% of participants were non-Hispanic White. [4] A change on a test score is not the same as preventing dementia, and the dementia analysis was underpowered. [6]
- Conflicts and funding. COSMOS investigators report NIH support, and some report ties to supplement-industry groups or companies in the trial paper's disclosures. [6] Read results with this in mind, not as a verdict either way.
Safety and who should check first
References
- US Preventive Services Task Force, JAMA 2022. Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: USPSTF Recommendation Statement. Read 2026-10-22.
- Sesso HD et al., JAMA 2012. Multivitamins in the prevention of cardiovascular disease in men: Physicians' Health Study II. Read 2026-10-22.
- Gaziano JM et al., JAMA 2012. Multivitamins in the prevention of cancer in men: Physicians' Health Study II. Read 2026-10-22.
- Baker LD et al., Alzheimers Dement 2023. Effects of cocoa extract and a multivitamin on cognitive function (COSMOS-Mind). Read 2026-10-22.
- Am J Clin Nutr 2024. Effect of multivitamin-mineral supplementation versus placebo on cognitive function: COSMOS-Clinic and meta-analysis. Read 2026-10-22.
- Sachs BC et al., Alzheimers Dement 2023. Impact of multivitamin-mineral and cocoa extract on incidence of mild cognitive impairment and dementia (COSMOS-Mind). Read 2026-10-22.
- Loftfield E et al., JAMA Netw Open 2024. Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts. Read 2026-10-22.
- National Institute on Aging, Dietary Supplements for Older Adults. Read 2026-10-22.