Should men over 40 take a multivitamin?

A standard multivitamin for men over 40 is not harmful but is unlikely to be meaningfully beneficial if your diet is reasonably varied, the evidence from large RCTs (Physicians' Health Study II with 14,641 male physicians followed for 11 years) shows multivitamin supplementation reduces cancer incidence by 8% but has no effect on cardiovascular events or mortality, suggesting modest benefit in nutritional insurance rather than meaningful disease prevention (Gaziano et al., JAMA, 2012).

The argument for a multivitamin in men over 40: insurance against subclinical deficiencies (B12, which requires active transport that declines with age; zinc; B6; folate) that are clinically meaningful but difficult to track through diet alone. The argument against: fat-soluble vitamins (A, D, E, K) accumulate, and megadose formulations can reach toxic levels; antioxidant vitamins (E, beta-carotene) at supplemental doses have negative trial data in smokers and possibly others; and the money is better spent on creatine, magnesium, vitamin D, and omega-3, which have more specific evidence.

Honesty Scale: Standard multivitamin for general health in men over 40, Promising (2) as nutritional insurance. Multivitamin for cardiovascular disease prevention, Unsupported (5) based on RCT evidence.

What to do: A basic men's multivitamin (not megadose) is a reasonable low-cost insurance product if your diet is variable. Prioritize the targeted supplements (D3, magnesium, omega-3, creatine) over relying on a multi to cover these specific needs, as multi formulations typically underdose these relative to evidence-based targets.

For the full picture, read The Supplementation Deep Dive