Should everyone take a multivitamin? (Updated 2026)

Last reviewed: April 28, 2026

Summary

The honest answer is 'it depends.' For healthy adults overall, daily multivitamins do not reduce heart disease, cancer, or premature death — but newer COSMOS trials suggest a small benefit for cognitive aging in adults over 60, and vegans genuinely do need to supplement B12 and several other nutrients. A vegan-formulated multivitamin is a sensible baseline for plant-based eaters; a generic 'everyone should take one' claim is not supported by current evidence.

Supported by 11 cited sources

Key Points

1USPSTF 2022 still concludes evidence is insufficient to recommend multivitamins to the general population for preventing cardiovascular disease or cancer; this remains the formal guideline position.
2COSMOS (2022, n=21,442) found no benefit for the primary composite cardiovascular endpoint (HR 0.98) or total invasive cancer (HR 0.97) over 3.6 years.
3Loftfield et al. 2024 (3 prospective US cohorts, ~390,000 adults, up to 27 years follow-up) found NO mortality benefit and a small early-follow-up hazard increase (HR 1.04, 95% CI 1.02-1.07), most plausibly explained by residual confounding (people start multivitamins when they feel less healthy) rather than true causal harm.
4Three independently designed COSMOS substudies (COSMOS-Mind, COSMOS-Web, COSMOS-Clinic) and the 2024 pooled meta-analysis show a small but statistically significant slowing of cognitive decline — roughly equivalent to about 2 years of cognitive aging in older adults. This is real, reproducible within the COSMOS family, and modest in absolute terms.
5Vegans need reliable B12 supplementation — this is non-negotiable. A standard regimen is 50-100 mcg cyanocobalamin daily or 2,000 mcg weekly. Vitamin D, iodine, omega-3 EPA/DHA from algal oil, zinc, selenium, and sometimes iron are common shortfalls on plant-based diets.
6Targeted supplementation of documented deficiencies is well-supported by evidence; a generic blanket recommendation that every healthy adult take a daily multi is not.
7USPSTF specifically recommends AGAINST beta-carotene and vitamin E supplements (D-grade), based on evidence of possible harm — particularly increased lung cancer risk in smokers.

Evidence Summary

The 2022 US Preventive Services Task Force statement concluded that current evidence is insufficient to recommend multivitamins for cardiovascular disease or cancer prevention in healthy non-pregnant adults (an 'I' statement), and recommended against beta-carotene and vitamin E (a 'D' statement). The 2022 COSMOS randomized trial confirmed no significant cardiovascular or total-cancer reduction. The 2024 NIH-AARP/PLCO/AHS pooled cohort analysis (Loftfield, JAMA Network Open) found no mortality

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All three cognitive substudies share a common parent trial (COSMOS) and the same supplement formulation (Centrum Silver); independent external replication is pending. COSMOS participants were predominantly older (≥60), well-nourished, and approximately 89 percent non-Hispanic White, which limits generalizability. Loftfield 2024 is observational, and the small early hazard increase is most plausibly residual confounding rather than causal harm. Cognitive effect sizes are statistically significant but modest in absolute terms, and clinical relevance for any individual is uncertain. No randomized trial has tested a vegan-specific multivitamin against placebo in vegans; the case for a vegan multi rests on the well-established individual-nutrient evidence rather than direct trial evidence.

Supporting Evidence

USPSTF finds insufficient evidence for broad multivitamin use to prevent major chronic diseases in general adults.

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COSMOS (Sesso et al. 2022, n=21,442, mean follow-up 3.6 years) found a hazard ratio of 0.98 (95% CI 0.86-1.11) for the primary composite cardiovascular endpoint and 0.97 (95% CI 0.88-1.08) for total invasive cancer in adults randomized to a daily multivitamin versus placebo. Effects were statistically null for the prespecified primary endpoints.

Caveats: COSMOS used Centrum Silver in a generally well-nourished older US population; results may not generalize to nutritionally deficient populations. Trial duration (3.6 years) is short for cancer outcomes.

Sources:

Sesso HD, Rist PM, Aragaki AK, et al.. Multivitamins in the prevention of cancer and cardiovascular disease: the COSMOS randomized clinical trial (2022)

Loftfield et al. 2024 pooled three large prospective US cohorts (NIH-AARP, PLCO, AHS) with up to 27 years of follow-up. Daily multivitamin use was not associated with reduced all-cause mortality; in early follow-up there was a small hazard increase (HR 1.04, 95% CI 1.02-1.07), most plausibly explained by residual confounding — people often start multivitamins after a health scare or when they feel less well — rather than a causal harm.

Caveats: Observational design cannot prove causation; residual confounding by indication is the leading explanation for the small early-follow-up hazard increase. Does not address quality-of-life or disease-specific outcomes.

Sources:

Loftfield E, O'Connell CP, Abnet CC, et al.. Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts (2024)

COSMOS-Mind (Baker 2023), COSMOS-Web (Yeung 2023), and COSMOS-Clinic with the pooled meta-analysis of all three (Vyas 2024) consistently show a small benefit on global cognition and episodic memory in adults aged 60 and older. The pooled effect on global cognition was approximately 0.07 SD — modest but statistically significant, and described as roughly equivalent to about 2 years of cognitive aging.

Caveats: All three substudies share the parent COSMOS trial and the same supplement formulation (Centrum Silver); independent external replication is pending. Participants were predominantly older, well-nourished, and ~89 percent non-Hispanic White. Absolute clinical relevance for any individual is uncertain.

Sources:

Major dietetics bodies (Academy of Nutrition and Dietetics, British Dietetic Association) and NIH ODS fact sheets agree that vegans require reliable B12 (typically 50-100 mcg cyanocobalamin daily or 2,000 mcg weekly). Vitamin D, iodine, omega-3 EPA/DHA from algal oil, zinc, selenium, and sometimes iron are commonly low on plant-based diets and well-covered by a vegan multivitamin.

Caveats: No randomized trial has tested a vegan-specific multivitamin against placebo in vegans; the case rests on well-established single-nutrient evidence and dietary intake studies. Individual needs vary; periodic labs (B12/MMA, vitamin D, ferritin, TSH) are preferable to guessing.

Sources:

USPSTF. Vitamin/mineral supplementation for prevention of CVD/cancer (2022)

USPSTF 2022 issued an 'I' statement (insufficient evidence) for general-population multivitamin use to prevent CVD or cancer, and a 'D' recommendation against beta-carotene and vitamin E. Single-nutrient supplementation guided by labs and clinical context — for example B12 in vegans, vitamin D in deficiency, iron in iron-deficiency anemia — is well-supported and routinely recommended.

Caveats: Population-level guidance differs from individual clinical decisions; targeted supplementation should be guided by diet, labs, and a clinician, not by a generic 'everyone should take one' claim.

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The Bottom Line

For the general population, daily multivitamins do not prevent heart disease, cancer, or premature death. There is a real but modest signal that they slow cognitive aging in adults over 60. For vegans, the calculus is different: B12 is non-negotiable, and several other nutrients (vitamin D, iodine, omega-3 DHA, zinc, iron, selenium) are commonly low on plant-based diets. A well-formulated vegan multi is a reasonable, low-effort way to cover these — not a magic pill, but a sensible baseline.

Practical Takeaways

If you are vegan, take a reliable B12 supplement (50-100 mcg cyanocobalamin daily or 2,000 mcg weekly) — this is the single most important supplementation decision on a plant-based diet. Consider a vegan-formulated multivitamin that covers B12, vitamin D (≥400 IU/10 mcg), iodine (around 150 mcg), zinc, and selenium, especially if your diet variety is limited. Algal omega-3 (EPA+DHA, around 250 mg combined per day) is reasonable; ALA from flax, chia, or walnuts converts inefficiently. Get vitamin D, B12 (and ideally MMA or holoTC), ferritin, and TSH checked periodically — supplement based on what is actually low rather than guessing. Avoid high-dose isolated beta-carotene or vitamin E supplements (USPSTF D recommendation, possible harm). Do not take a multivitamin expecting it to extend your lifespan or prevent cancer — that is not what the evidence shows. If you are over 60, the cognitive signal from COSMOS is interesting but modest; a daily multi is a low-cost, low-risk choice if you want to act on it, not a guaranteed benefit.