About a third of American adults take a multivitamin. For many, it is a kind of insurance policy: one pill a day to cover whatever the diet misses. It is an appealing idea. So does it work? The answer depends a lot on who you are.
What the big studies found
Researchers have spent decades testing whether multivitamins help healthy people live longer or avoid serious disease. A few highlights:
- The U.S. Preventive Services Task Force reviewed the evidence in 2022 and concluded there is not enough evidence to say whether multivitamins prevent heart disease or cancer in healthy adults. It also recommended against taking beta-carotene or vitamin E supplements for this purpose, since beta-carotene raised lung cancer risk in smokers. You can read the Task Force recommendation online.
- The Physicians' Health Study II, which followed about 14,000 male doctors for over a decade, found a small reduction in cancer, about 8 percent, but no effect on heart disease.
- A large 2024 analysis of nearly 400,000 adults found that people who took a daily multivitamin did not live longer than those who did not.
- The COSMOS trials found a possible small benefit for memory in older adults taking a daily multivitamin. These findings are interesting but need confirming.
Put simply, for a healthy adult who eats reasonably well, a multivitamin is unlikely to make a meaningful difference to long-term health. The best evidence still points to food, activity, sleep and not smoking.
Who is more likely to benefit
That said, multivitamins can help people who have real gaps:
- Older adults, who often eat less and absorb some nutrients, like vitamin B12, less well. See vitamin B12 for adults over 50.
- People who are pregnant or planning a pregnancy. A prenatal vitamin with folic acid is strongly recommended. See our prenatal vitamins guide.
- People on restricted diets, including vegans, people with food allergies, or anyone eating very little because of illness or low appetite.
- People after weight-loss surgery, who need lifelong supplements under a doctor's care.
- People with conditions that affect absorption, like celiac disease or inflammatory bowel disease.
- People taking medicines that deplete nutrients, such as metformin, which can lower B12. See supplement and drug interactions.
Is it a waste of money for everyone else?
Not necessarily a waste, but not much of an investment either. If you like the peace of mind and choose a sensible, inexpensive product, a basic multivitamin is generally safe. The bigger risks come from mega-dose products, or from stacking a multivitamin on top of several other supplements so that you go over upper limits. See percent daily value on supplement labels.
How to choose a sensible multivitamin
Aim for about 100 percent of the Daily Value
Look for most vitamins and minerals at around 100 percent of the Daily Value, not 1,000 or 5,000 percent. More is not better, and some nutrients can build up.
Match it to your age and sex
- Men and women after menopause usually do not need extra iron. Look for a "50+" or "iron-free" formula unless your doctor says otherwise. See iron supplements: who needs them.
- Women of childbearing age benefit from 400 mcg of folic acid and usually some iron.
- Older adults benefit from a formula with B12 and vitamin D.
Do not expect calcium to be complete
Calcium is bulky, so most one-a-day multivitamins contain only a small amount. If you need more, get it from food or a separate supplement. See calcium and bone health.
Skip the extras
Herbs, "energy blends," and proprietary mixes add cost without clear benefit. See proprietary blends explained.
Choose a tested product
A USP Verified seal means an independent lab checked that the product contains what the label says and dissolves properly. Many affordable store brands carry it.
Pick a form you will take
Tablets are usually the cheapest. Gummies are easier to swallow but often contain less, lack iron and minerals, and contain sugar. See capsules vs powders vs gummies.
Tips for taking one
- Take it with a meal. It helps absorption of fat-soluble vitamins and reduces stomach upset. See taking supplements with or without food.
- Tell your doctor you take it, especially before blood tests. Biotin in some formulas can affect lab results. See supplements and lab tests.
- If you smoke or used to smoke, avoid products with high-dose beta-carotene.
- Keep it away from children, especially if it contains iron.
The bottom line
A multivitamin is not a substitute for a healthy diet, and for most well-fed adults it will not add years to your life. For older adults, pregnant women, people on restricted diets and people with absorption problems, it can fill real gaps. If you take one, choose a simple, tested product near 100 percent of the Daily Value. Visit our daily essentials goal page and vitamins category for more.