Do multivitamins work? Dietitians explain when they help — and when they don't

According to data from the National Health and Nutrition Examination Survey, 57% of U.S. adults use dietary supplements, with multivitamins being the most commonly used. Yet, despite their popularity, there’s still plenty of debate over whether multivitamins actually work. As with most things related to nutrition and health, the answer is more nuanced than a simple yes or no.

At their core, multivitamins are “designed to supplement your diet, providing essential vitamins and minerals that may be missing in your daily food intake,” says Juliana Vocca, MS, RD, a private-practice dietitian.

Some products also include additional ingredients — such as whole-food blends, probiotics or antioxidants — marketed to support specific areas of health, including eye, gut or heart health.

If you eat a mostly balanced diet, you likely don’t need a multivitamin, according to Elizabeth Keck, MS, RD. “If you eat fruits, vegetables, whole grains, milk and protein foods like meat, fish or beans — or foods with added vitamins — you’re probably getting the nutrients you need from food,” she says.

That said, some people do have higher nutrient needs or greater difficulty meeting them through food alone. Pregnant or breastfeeding people, for example, need more of certain nutrients to support the health of mom and baby. Other groups — including older adults, vegans and people with certain medical conditions — may fall short due to factors like food restrictions, reduced appetite, chewing or swallowing difficulties or changes in digestion that affect nutrient absorption.

So, with all of that in mind, I put on my dietitian cap, dove into the science and spoke with three fellow registered dietitians to answer the question: Do multivitamins actually work — and who, if anyone, might benefit from taking one?

What do multivitamins actually do?

Multivitamins are dietary supplements that contain a combination of essential vitamins and minerals — aka nutrients your body can’t make on its own and must get from food (or, in the case of vitamin D, from both diet and sunlight). Although they’re needed only in small amounts — hence the term micronutrients — vitamins and minerals play a critical role in keeping your body healthy and energized.

Multivitamins can vary widely in their ingredients and dosages. Some are relatively basic and designed simply to help fill nutritional gaps, while others are formulated to meet the needs of specific life stages, such as pregnancy or adulthood after age 50. Some are also intended to support particular health concerns, like heart health or hair, skin and nails.

It’s also important to note that multivitamins are meant to supplement your diet, not replace it. Whole foods provide a complex mix of nutrients and other beneficial compounds that supplements can’t fully replicate, which is why a balanced diet remains the foundation of good health.

Are multivitamins worth it?

The answer depends on why you’re taking one. Below, we break down the most common reasons people consider taking a multivitamin — and whether it’s actually likely to help.

They can help correct nutritional deficiencies

“This is where multivitamins shine,” says registered dietitian Jamie Lee McIntyre, MS, adding, “If bloodwork shows you’re low in something like vitamin D or iron, or your diet makes certain nutrients hard to get, supplements can be really helpful.”

Just keep in mind that depending on the severity of your deficiency, your health care provider may recommend a high-dose single-nutrient supplement instead, as multivitamins typically don’t contain high enough doses to correct serious deficiencies. However, if the issue is more that you’re getting inadequate amounts of a nutrient, a multivitamin can be a helpful way to shore up those gaps.

They’re important for supporting pregnancy and breastfeeding

Pregnancy is a period of rapid growth, which means nutrient needs increase to support the health and development of both the parent and the baby, as well as the placenta. While overall nutrient requirements rise, some nutrients are especially important for maternal health and fetal brain and physical development. These include iron, omega-3 fatty acids (especially DHA), calcium, choline, iodine, magnesium, vitamin B6, vitamin B12, vitamin D and zinc.

For this reason, the American College of Obstetricians and Gynecologists (ACOG) and the Academy of Nutrition and Dietetics recommend that pregnant women take a prenatal supplement throughout pregnancy and for at least six months after delivery, or for as long as they are breastfeeding.

One nutrient that’s particularly important is folic acid, which helps prevent neural tube defects. The challenge is that folic acid is needed in higher amounts very early in pregnancy — sometimes before a person even knows they’re pregnant. Because of this, the American Academy of Pediatrics recommends that anyone who may become pregnant take 400 micrograms (mcg) of folic acid per day, either as a single-nutrient supplement or as part of a multivitamin.

They may help improve energy levels

A common reason people take a multivitamin is to try to boost energy levels — but are they actually effective? According to a 2020 review published in Nutrients, low levels or deficiencies of certain vitamins and minerals — including iron, vitamin C, magnesium, zinc and B vitamins — are associated with increased feelings of fatigue. If you’re not getting enough of one or more of these nutrients through your diet, taking a multivitamin may help you feel more energized.

However, if your diet already meets your nutrient needs, it’s unlikely that a multivitamin will make a noticeable difference in your energy levels.

They may help improve hair, skin and nail health

Similar to energy levels, you may see improvements in hair, skin and nail health after starting to take a multivitamin on a regular basis — but typically only if you were previously deficient in key nutrients involved in these areas, such as iron and zinc, McIntyre says. “If you’re already eating well, adding more vitamins usually — and unfortunately — won’t suddenly give you glowing skin or thicker hair.” Also keep in mind that hair, skin and nails change slowly, so it can take weeks, if not months, to notice any differences.

They probably won’t help prevent chronic disease

According to older survey data, one of the main reasons adults take a multivitamin is to try to prevent disease — but does it actually work? Unfortunately, several large studies indicate that the answer appears to be no.

A 2024 analysis of nearly 400,000 healthy U.S. adults followed for more than 20 years found no association between multivitamin use and a lower risk of death. Similarly, a 2023 study published in The American Journal of Clinical Nutrition found no protective effect against cancer in older adults, and a 2018 review from the American Heart Association reported no benefit of multivitamin use for reducing the risk or outcomes of heart disease.

Some studies have suggested modest benefits in specific groups, particularly people with nutrient deficiencies or limited access to a varied diet. However, in generally well-nourished populations, large reviews consistently show little to no protection against major chronic diseases from taking a daily multivitamin.

That doesn’t mean vitamins are useless. “Vitamins work best as part of a healthy lifestyle — not as a substitute for a balanced diet,” Vocca says.

Part of the challenge is that studying multivitamins is complicated. Products vary widely by brand and formulation, people absorb nutrients differently and those who take multivitamins are often more health-conscious overall, making it difficult to isolate their specific effects.

Do you need a multivitamin?

Some groups are more likely to benefit from a multivitamin, including:

• Pregnant people: Pregnancy increases the need for nutrients such as folic acid and iron. A prenatal multivitamin can help ensure that both you and your baby get the nutrients needed for healthy growth and development.

• Lactating people: Breastfeeding also increases nutrient and calorie needs. Many people continue taking their prenatal vitamin during lactation, though some may choose a postnatal or breastfeeding-specific formulation.

• Vegans and vegetarians: Research shows that plant-based diets can be low in certain nutrients, particularly vitamin B12, iron and vitamin D. A multivitamin formulated for plant-based diets can help fill these common gaps.

• People with digestive disorders: Conditions such as celiac disease or Crohn’s disease can impair the body’s ability to absorb nutrients, increasing the risk of deficiencies.

• People taking certain medications: Some medications interfere with nutrient absorption. “These include proton pump inhibitors for acid reflux, metformin, cholesterol-lowering statins, steroids and diuretics,” says Vocca.

• Bariatric surgery patients: Weight loss surgery alters the digestive system, which can significantly affect how well the body absorbs vitamins and minerals. For this reason, lifelong supplementation is often recommended.

• Adults over 50: As we age, the body’s ability to absorb certain nutrients declines. Factors such as reduced appetite and chewing or swallowing difficulties can also make it harder to meet nutrient needs through food alone. Multivitamins formulated for older adults can help address these changes.

• People with limited or inconsistent food intake: Chronic illness, poor appetite, chewing or swallowing difficulties or very restrictive diets can make it challenging to meet nutrient needs through food alone. In these cases, alternative multivitamin formats, such as liquid or powdered options, may be easier to take.

• People with diagnosed nutrient deficiencies: Bloodwork showing low levels of certain vitamins or minerals may signal the need for targeted supplementation. While single-nutrient supplements are often recommended, a multivitamin may help maintain adequate nutrient levels once a deficiency has been corrected.

When in doubt, the best course of action is to talk with your doctor or other health care professional about whether a multivitamin is necessary or appropriate.

Who doesn’t actually need a multivitamin

If you don’t fall into any of the groups above, you likely don’t need a multivitamin. “Most healthy adults who eat a wide variety of foods do not need a multivitamin,” Keck says.

McIntyre adds that many people spend money on supplements they don’t need. If you’re generally healthy and eating a balanced diet, you can probably skip the multi. If you’re unsure, consider talking with a doctor or registered dietitian.

Another important tip? If you’re already taking supplements, like protein powder or collagen, make sure to check the supplement label before you invest in a multivitamin. Oftentimes, these supplements are fortified with vitamins and minerals, so stacking them with a multivitamin can increase your risk of consuming potentially toxic amounts of certain nutrients.

Are multivitamins ever risky?

Yes — especially if you overdo it.

Many nutrients can cause side effects or even serious complications when taken in excess. “Look for a multivitamin that doesn’t greatly exceed 100% of the Daily Value for most nutrients,” McIntyre says.

Vocca notes that this is particularly important for fat-soluble vitamins — A, D, E and K — which are stored in the body and can build up over time.

“I’ve seen people double-dosing vitamins and minerals found in multiple supplements,” McIntyre says. Always check labels if you take more than one supplement.

While nutrient toxicity is a concern for adults, it’s especially risky for children. Kids are more susceptible to excessive intakes due to differences in their metabolism, and gummy vitamins can be easily mistaken for candy. If you have young children at home, it’s important to keep supplements out of reach — and ideally out of sight.

Medical considerations

Multivitamins can also interact with certain medications or be unsafe for people with specific health conditions. For example, some supplements may interfere with blood thinners or other prescription drugs, and people with kidney disease may need to limit nutrients like potassium, phosphorus or vitamin A. If you take medications or have a chronic health condition, it’s best to check with a health care professional before starting a multivitamin.

Regulatory concerns

Lastly, because the Food and Drug Administration (FDA) does not require dietary supplements to be tested for safety, purity or label accuracy before they reach the market, it’s important to choose products from reputable brands. Look for supplements that are third-party tested for purity and potency by organizations such as NSF, Informed Choice or the United States Pharmacopeia (USP).

How to choose the right multivitamin

Still think that a multivitamin is right for you? Here are some key factors to keep in mind when deciding what to buy:

• Formulation: The most important factor is choosing a product formulated to meet your needs. For example, if you’re pregnant, opt for a prenatal vitamin rather than a standard multivitamin. Many brands also offer formulations for men and women. If you’re unsure which nutrients or dosages are appropriate for you, work with a registered dietitian or health care provider for personalized guidance.

• Form: Multivitamins come in many forms, including capsules, chewable tablets, gummies, liquids and powders. Choose one you can take safely and comfortably on a daily basis (or as directed).

• Purity and potency testing: To help ensure you’re getting what’s listed on the label — and nothing else — look for a multivitamin that’s rigorously tested for purity and potency by a reputable third-party organization. Some brands also make their testing results publicly available.

• Diet appropriateness: If you have food allergies or follow a specific eating pattern, such as a vegan or gluten-free diet, look for products that meet those needs. Third-party certifications can make this easier to identify, but the ingredient list is still your best resource.

• Overall value: Since you’ll likely be taking your multivitamin regularly, choose a product that fits comfortably into your monthly budget.

Is it good to take a multivitamin every day?

If a multivitamin helps fill nutrient gaps in your diet, taking it daily is usually best. Consistency helps ensure your body has a steady supply of essential vitamins and minerals. Not everyone needs a multivitamin, but for most healthy adults, taking one daily is generally safe — as long as you’re not exceeding recommended amounts from other supplements or fortified foods. If you have specific health conditions or take medications, it’s best to talk with a health care provider to be sure a multivitamin is appropriate for you.

Do multivitamins work for kids?

Like adults, not all kids need a multivitamin. In most cases, children can get the nutrients they need from a balanced diet alone, and the American Academy of Pediatrics does not recommend daily multivitamin use. That said, a kids’ multivitamin may be helpful for some — such as picky eaters or those with restricted diets — to help ensure they’re getting nutrients that support healthy growth and development. Choose a multivitamin specifically formulated for children, since their nutritional needs differ from adults’, and excessive intake of certain nutrients can be harmful.