Do multivitamins actually do anything?

For a well-nourished person, the findings are underwhelming for the industry. In 2022 the US Preventive Services Task Force reviewed the evidence for healthy adults without a known deficiency and concluded it was insufficient to tell whether multivitamins prevent cardiovascular disease or cancer. For two single nutrients the verdict was sharper: it recommends against beta-carotene and vitamin E, because beta-carotene raises lung cancer risk in smokers and vitamin E shows no benefit. The systematic review behind it (Fortmann and colleagues) found at most a small, borderline reduction in cancer risk in men and no effect on cardiovascular disease.

The picture is not entirely one-sided. COSMOS-Web, a three-year randomized trial in over 3,500 adults aged 60 and older, found that a daily multivitamin produced slightly better episodic memory than placebo, both after one year and on average across three. The effect was small and showed up on one of several measures, but it was real, and it hints that older brains may get a marginal benefit.

So where does this land? For the outcomes people most hope for, living longer and avoiding cancer and heart disease, a multivitamin gives an already well-nourished person little or no measurable effect. Where there is a genuine deficiency or a raised need, such as pregnancy, certain diets or a documented low level, targeted topping-up is another matter entirely. A broad multivitamin taken for prevention rarely fixes anything; mostly it fills a gap where the food already suffices.

The multivitamin is cheap, feels responsible and asks nothing of you. Swallowing a tablet becomes a small daily receipt that you're taking care of yourself, an insurance policy against a vague worry that your diet falls short. That feeling sells. Supplements are a multibillion-dollar industry where a bottle costs little to make and can be marketed with health words that never have to be proven the way a drug does. Phrases like "supports your immune system" or "gives you energy" are legally vague enough that they can never be disproven. Add confirmation bias: someone who feels good credits the pill, while someone who notices nothing keeps taking it just in case. No single player profits from saying food is usually enough.

If you have a demonstrated deficiency or a raised need — something a blood test or a clinician can confirm — targeted supplementation makes sense. Without that, a broad multivitamin rarely does measurable good for a well-nourished body, and the money is better spent on food. Spend your effort on what actually moves your health: enough protein, vegetables, sleep and movement. A multivitamin rarely harms, but it does not replace a diet that falls short, and it is rarely the answer to tiredness or feeling off.