Short answer: Most healthy adults who eat a varied diet don’t need a multivitamin. Large studies have found that multivitamins don’t help people live longer or lower heart disease risk. They can be useful if you’re pregnant or planning a pregnancy, vegan, over 50, on a very restricted diet, or have a condition or medicine that affects absorption. If you take one, choose a tested product with about 100% of the Daily Value for most nutrients, not megadoses.
About a third of American adults take a multivitamin, often as nutritional “insurance”. It’s an understandable habit: multivitamins are cheap, convenient and feel like they can only help. But decades of research have produced a more mixed picture. For some people, a multivitamin fills real gaps; for many others, it adds little to a reasonable diet. This guide summarizes what the major studies found, who’s most likely to benefit, and how to choose a good product.
If you’re thinking about a specific nutrient instead, see our guides to vitamin D supplements, iron supplements and types of magnesium.
Multivitamins at a glance
- Longer life
- No benefit found in large studies
- Heart disease
- No reduction in risk in trials
- Cancer
- One large trial found a small reduction in men; overall evidence is insufficient
- Memory in older adults
- Some evidence of a modest benefit
- Most likely to benefit
- Pregnancy, vegans, older adults, restricted diets, absorption problems
- What to look for
- USP or NSF seal, about 100% DV, no megadoses
What the research shows
Major studies on multivitamins
- Lifespan: an NIH analysis that followed about 390,000 healthy US adults for more than 20 years found that people who took a daily multivitamin didn’t live longer than those who didn’t. In fact, the risk of death was slightly higher in the first years of follow-up, though that may reflect who chooses to take supplements (Loftfield et al., 2024).
- Heart disease and cancer: in the Physicians’ Health Study II, about 14,600 male doctors took a multivitamin or placebo for around 11 years. The multivitamin group had an 8 percent lower rate of total cancer, but no reduction in heart attacks or strokes (Gaziano et al., 2012).
- Official guidance: in 2022, the US Preventive Services Task Force concluded there isn’t enough evidence to recommend multivitamins for lowering the risk of heart disease or cancer in healthy adults. It recommended against beta-carotene and vitamin E supplements for this purpose.
- Memory: the COSMOS trials, involving more than 5,000 adults over 60, found that a daily multivitamin modestly slowed age-related memory decline over 2 to 3 years compared with placebo. The effect was small, and more research is needed.
Limited evidence Taken together, the research suggests multivitamins are generally safe but aren’t a shortcut to better health for people who are already well nourished. Their real value is in correcting or preventing specific shortfalls.
Who may benefit from a multivitamin
- Pregnant women and those who could become pregnant: the CDC recommends 400 mcg of folic acid daily for anyone who could become pregnant, to lower the risk of neural tube defects. Prenatal vitamins also provide iron, iodine and vitamin D. Ask your doctor which one to take.
- Vegans and some vegetarians: vitamin B12 is found almost only in animal foods, so vegans need a supplement or fortified foods. Vitamin D, iodine, zinc, iron and omega-3s can also run low.
- Adults over 50: stomach acid declines with age, which reduces absorption of vitamin B12 from food. The recommendation is to get most B12 from fortified foods or supplements. Older adults also often fall short on vitamin D and calcium.
- People on restrictive or low-calorie diets: eating fewer than about 1,200 calories a day, or cutting out whole food groups, makes it hard to meet nutrient needs.
- After weight-loss surgery: lifelong supplements are usually required, often at higher doses than a standard multivitamin.
- People with absorption problems: celiac disease, Crohn’s disease and some other digestive conditions reduce nutrient absorption.
- Certain medicines: long-term metformin and acid-reducing medicines can lower B12 levels. Some anti-seizure medicines affect vitamin D and folate.
- People with limited access to food, or whose diet is very low in fruit, vegetables and whole grains.
Who probably doesn’t need one
If you’re a healthy adult under 50 who eats a varied diet with fruit, vegetables, whole grains, protein foods and some dairy or fortified alternatives, a multivitamin is unlikely to make a noticeable difference. It won’t make up for a poor diet either: whole foods provide fiber, protein and thousands of plant compounds that a pill doesn’t. If you take one anyway, it’s very unlikely to cause harm at standard doses, but it’s an optional extra rather than a necessity.
Common nutrient gaps in the US
According to the Dietary Guidelines for Americans, the nutrients most people fall short on are fiber, potassium, calcium and vitamin D. Notice that only vitamin D is something a standard multivitamin covers well:
| Nutrient | In a typical multivitamin? | Better sources |
|---|---|---|
| Fiber | No | Beans, lentils, whole grains, fruit, vegetables |
| Potassium | Only a small amount | Potatoes, beans, bananas, leafy greens, yogurt |
| Calcium | Usually only 10–25% DV | Dairy, fortified plant milks, tofu made with calcium |
| Vitamin D | Yes, often 100% DV or more | Sunlight, oily fish, fortified milk |
| Magnesium | Usually only a small amount | Nuts, seeds, whole grains, beans |
Shortfall nutrients from the Dietary Guidelines for Americans 2020–2025. Multivitamin contents vary by product.
Potassium, calcium and magnesium are bulky minerals, so there isn’t room to fit a full day’s worth into one tablet. Food is the main source. Our guides to foods high in potassium, magnesium-rich foods and high-fiber foods can help.
How to choose a multivitamin
- Look for a testing seal: USP Verified or NSF Certified means an independent lab confirmed the product contains what the label says and isn’t contaminated.
- Aim for about 100% of the Daily Value: for most vitamins and minerals. More isn’t better, and some nutrients are harmful in excess.
- Match iron to your needs: women who menstruate generally need a formula with iron. Men and postmenopausal women usually don’t, and should choose iron-free or “50+” formulas unless a doctor advises otherwise.
- Check vitamin A: look for a product where much of the vitamin A comes from beta-carotene rather than retinol, especially during pregnancy. Smokers and former smokers should avoid high-dose beta-carotene.
- Choose B12 if you’re vegan or over 50: most multivitamins include it, but check.
- Be wary of gummies: they’re easy to take but often contain sugar and leave out iron, calcium and other minerals. They’re also tempting to children.
- Skip the extras: herbal blends, “energy” boosters and proprietary blends add cost without proven benefit.
Our guide to reading a supplement label walks through the Supplement Facts panel step by step.
Safety and interactions
Who should be careful
- Doubling up: if you also take vitamin D, calcium, iron or other single supplements, add up the totals to stay under the upper limits.
- Warfarin: vitamin K in many multivitamins can affect warfarin. Keep your intake consistent and tell your doctor.
- Children: keep multivitamins, especially those with iron, out of reach. Iron overdose is dangerous for young children.
- Pregnancy: avoid products with high-dose preformed vitamin A (retinol), which can cause birth defects in large amounts. Use a prenatal vitamin your doctor recommends.
- Medicines: minerals such as calcium, iron and zinc can reduce absorption of levothyroxine and some antibiotics. Take them several hours apart.
- Kidney disease: ask your doctor before taking a multivitamin, as some minerals can build up.
Food first
A multivitamin can fill specific gaps, but it can’t replace the benefits of a healthy diet. Fruit, vegetables, beans, nuts, whole grains and fish provide fiber and plant compounds that are linked to better long-term health and that no tablet contains. Start by looking at what you eat, then use supplements to fill the gaps that remain. Our food nutrition lookup can show how much of each nutrient your favorite foods provide.
Check the nutrients in your food. Look up full USDA nutrition labels for thousands of foods.
Multivitamin FAQ
Is it bad to take a multivitamin every day?
No. For most people, a standard multivitamin with about 100% of the Daily Value is safe to take daily. Problems mainly come from high-dose products or combining several supplements.
When is the best time to take a multivitamin?
With a meal, which improves absorption of fat-soluble vitamins and reduces the chance of an upset stomach. Choose a time you’ll remember.
Do multivitamins give you energy?
Only if you’re low in a nutrient such as iron or B12. For people who aren’t deficient, there’s no good evidence that multivitamins boost energy.
Are gummy vitamins as good as tablets?
They can be, but many gummies contain fewer minerals and added sugar. Check the label and look for a third-party testing seal.
Should men and women take different multivitamins?
The main difference is iron. Women who menstruate usually need more iron, while most men and postmenopausal women don’t need iron in a multivitamin.
Sources
- NIH Office of Dietary Supplements. Multivitamin/mineral supplements: fact sheet for health professionals.
- National Institutes of Health (2024). Daily multivitamin use not linked to lower risk of death (Loftfield et al.).
- Gaziano JM, et al. (2012). Multivitamins in the prevention of cancer in men: the Physicians’ Health Study II randomized controlled trial.
- US Preventive Services Task Force (2022). Final recommendation on vitamin, mineral and multivitamin supplements for heart disease and cancer risk.
- Healio (2024). Third COSMOS study links daily multivitamin supplementation to cognitive benefits.
- CDC. About folic acid.
- Dietary Guidelines for Americans, 2020–2025.