Multivitamin

Does it work?

• -Mostly no. For healthy people who eat a reasonably varied diet, a daily multivitamin doesn't lower your risk of dying, heart disease, or cancer — the largest trials and reviews keep landing on "no meaningful benefit." It's a cheap insurance policy against a problem most well-fed lifters don't have. Real, diagnosed deficiencies are worth treating; a generic multi as a catch-all is not where your money goes.

The catch

• -Big trials don't show it works for prevention. The USPSTF systematic review and the COSMOS trial found multivitamins didn't meaningfully cut cardiovascular events, cancer, or death in healthy adults — and a 2024 cohort of 390,000 people found no mortality benefit at all.
• -A pill can't fix a bad diet. Multivitamins deliver small doses of isolated nutrients, not the fiber, protein, and food matrix you'd get from actually eating better — which is what the prevention data actually rewards.
• -Shotgun dosing isn't free of downside. Some ingredients (beta-carotene, vitamin E) showed harm in trials, and 'more vitamins' isn't a benefit if you weren't short on them in the first place.

Better option

• -Eat a varied diet with enough protein, fruit, and vegetables, and if you suspect a shortfall, test for it (vitamin D, iron, B12) and treat the specific gap instead of guessing with a multi.

Safety

• -Generally low-risk at label doses, but it is not harmless: skip beta-carotene if you smoke (raised lung cancer risk in trials) and avoid mega-dose 'high potency' formulas.
• -A multi can mask or delay diagnosis of a real deficiency — if you have symptoms (fatigue, hair loss, low energy), get bloodwork rather than self-treating.
• -Watch for stacking: if you already take vitamin D, iron, or a greens powder, a multi can push some nutrients (iron, vitamin A, niacin) past safe levels.

Key research

• Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation StatementJAMA · 2022 · Position stand
• Vitamin and Mineral Supplements for the Primary Prevention of Cardiovascular Disease and Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task ForceJAMA · 2022 · Systematic review
• Multivitamin-multimineral supplementation and mortality: a meta-analysis of randomized controlled trialsAm J Clin Nutr · 2013 · Meta-analysis
• Multivitamin Use and Mortality Risk in 3 Prospective US CohortsJAMA Netw Open · 2024 · Cohort study
• Multivitamins in the prevention of cancer in men: the Physicians' Health Study II randomized controlled trialJAMA · 2012 · RCT

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