Quick answer

A multivitamin adds vitamins and minerals to what you get from food, which matters most when your diet falls short. In a study NIH cites, about three quarters of men had adequate intakes from food alone and 84% did once a multi was counted. Large trials have not shown that a daily multi helps people live longer.¹

Key facts

About one third of US adults take a multivitamin and mineral supplement.¹
There is no standard multi: each maker chooses which nutrients go in and how much.¹
Basic multis usually contain only small amounts of calcium and magnesium.²
Added to fortified foods and other supplements, a multi can push iron, vitamin A, zinc, niacin or folic acid over their upper limits.²
A multi that contains vitamin K can change how warfarin works, so ask first if you take it.¹

What a multivitamin is

Multis have no standard or regulatory definition. Each maker decides which vitamins, minerals and other ingredients go in, and in what amounts.¹

Most multis fall into a few types. Basic ones are taken once a day and keep most nutrients near the amounts people need. High-potency products go well above those amounts, and specialized ones add herbs or other ingredients for a stated purpose.¹

Some multis are sold for a purpose such as energy, sport, immune function or eye health. These often add herbs or other ingredients such as green tea, coenzyme Q10 or probiotics, and some contain nutrients well above the Daily Value.^1,2

Labels show each nutrient as a percentage of its Daily Value (DV). The DV is often, but not always, close to the Recommended Dietary Allowance, the daily amount that covers the needs of nearly all (97 to 98%) healthy people.^1,2

So 100% of the Daily Value means one serving gives roughly a full day's recommended amount of that nutrient for many adults, before food is counted. For some nutrients the DV is set at the higher need of one group: the iron DV of 18 mg matches what women aged 19 to 50 need, while men need 8 mg.^1,3

What the evidence shows

Each claim below carries a grade and the amount behind it. All three are about meeting your needs: none of them means that more than you need does more.

Helps fill gaps in vitamin and mineral intake when diet falls short*¹

Moderate evidence

The NIH Office of Dietary Supplements states that taking a multivitamin and mineral raises nutrient intakes and helps people reach recommended amounts when food alone does not. In a study of 90,771 adults that it cites, about three quarters of men had adequate intakes from food alone and 84% did once a multivitamin was counted. This product supplies 50% or more of the Daily Value for 18 of its 20 listed nutrients; calcium (4%) and magnesium (12%) are token amounts.

Amount studied: One basic multivitamin and mineral a day, with most nutrients close to recommended amounts

Provides B vitamins that contribute to normal energy-yielding metabolism*^4,5

Moderate evidence

Thiamin, riboflavin, niacin, pantothenic acid, vitamin B6, vitamin B12 and biotin are needed by the enzymes that release energy from food; niacin alone is part of a coenzyme used by more than 400 enzymes. 'Contributes to normal energy-yielding metabolism' is the wording European regulators permit for each of these vitamins, and this product supplies more than the Daily Value of each. It does not mean extra B vitamins give more energy to someone who already gets enough.

Amount studied: The recommended daily intake of each B vitamin, from food and supplements together

Provides vitamin C, vitamin D, zinc and selenium, which contribute to normal immune function*^4,6

Moderate evidence

Each of these nutrients, along with vitamin A, vitamin B6, vitamin B12, folate and copper, has an established role in the normal working of the immune system, and each carries that permitted wording in the EU list of nutrient-function statements. NIH describes zinc as having a role in immune function. This is about meeting needs. No trial shows that this formula makes people ill less often.

Amount studied: The recommended daily intake of each nutrient, from food and supplements together

The notes under each claim come from our review of Men's Multi, so 'this product' there means that formula. The roles they describe belong to the nutrients themselves.⁴

People who take multis often already get more vitamins and minerals from food than people who do not, while the groups most likely to fall short are the least likely to take one.^1,2

The two longest trials tested one formula, Centrum Silver: 14,641 male doctors took it for a median of 11.2 years, and 21,442 older adults for a median of 3.6 years. Trials like these have not shown that a daily multi helps people live longer.¹

Results from one multivitamin cannot be applied to others: no two large trials have used the same nutrients in the same amounts.¹

No US government health agency, private health group or health professional organization promotes regular use of multivitamins.¹

Who might consider one

People who do not get enough vitamins and minerals from food, eat low-calorie diets, have a poor appetite or avoid certain foods, such as strict vegetarians and vegans, might consider a multi.²

People over 50 should get recommended amounts of vitamin B12 from fortified foods or supplements, because their bodies might not absorb enough of the B12 found naturally in food.²

All women and teen girls who could become pregnant should get 400 mcg of folic acid a day from supplements, fortified foods or both, on top of the folate in a healthy diet.⁷

If none of these fits you and you eat a varied diet, a multi has little to do. It fills gaps, and NIH notes that people who take multis often get more vitamins and minerals from food in the first place.²

A multi cannot take the place of a varied diet: foods also supply fiber and other components that a multi does not. Federal dietary guidelines say most nutrients should come from food and drinks.²

Multivitamins for men

The main difference for men is iron. Men need 8 mg a day, less than half the 18 mg that women aged 19 to 50 need, and on average men already take in 16 to 18 mg a day from food.³

Multis with iron, especially those designed for women, typically provide 18 mg, 100% of the Daily Value. Multis for men or seniors often contain less iron or none.³

So for most men, a multi with little or no iron fits better than one made for women, unless a doctor has found a need for more.³

How much to take

Basic multis are taken once a day and contain all or most vitamins and minerals, most of them in amounts that do not exceed the Daily Value or the recommended intake.^1,2

High-potency products contain some vitamins or minerals well above the Daily Value, in some cases above the upper limit, and may come as two or more pills to take each day.^1,2

Going over an upper limit is more likely when a multi is combined with single vitamin or mineral supplements, or with fortified foods and drinks such as breakfast cereals.^1,2

Taking two of a once-a-day multi does not double what it does for you. It doubles every nutrient, including the ones that already sit close to their upper limits. The dosage guide sets out those limits.⁸

What's in ours

What’s in ours

Men's Multi: Vitamin A, 600 mcg RAE per serving, from the label

Our Men's Multi is two capsules once a day with a meal. Its label lists 20 vitamins and minerals, with no iron, iodine or vitamin K, and only small amounts of calcium and magnesium.

Side effects, medicines, and who should ask first

Studies of multivitamin users report no adverse effects except minor stomach and gut complaints, which people taking a placebo had too.¹

Combined with fortified foods or other supplements, a multi can push some nutrients over their upper limits. NIH names iron, vitamin A, zinc, niacin and folic acid.²

There is no upper limit for a multivitamin as a whole: each nutrient has its own. Adult limits include 35 mg of niacin from supplements, 1,000 mcg of folic acid from supplements and fortified foods, and 350 mg of magnesium from supplements and medicines. From all sources combined, they include 40 mg of zinc, 45 mg of iron, 3,000 mcg of preformed vitamin A, 100 mcg (4,000 IU) of vitamin D and 100 mg of vitamin B6. Beta-carotene has no upper limit.^3,5,7,8,9,10

In two trials, smokers who took 20 mg of beta-carotene a day, or 30 mg with vitamin A, had more lung cancer than those on placebo. NIH says smokers, and possibly former smokers, should avoid multis with large amounts of beta-carotene or vitamin A.¹

Accidental swallowing of iron supplements caused about a third of the poisoning deaths in US children reported from 1983 to 1991. Keep any product that contains iron out of children's reach.³

Ask your pharmacist or doctor first

Vitamin K counters warfarin, and the warfarin label lists more vitamin K in the diet among the factors that weaken its effect. NIH says people who take warfarin should talk with their health care provider before taking any multivitamin that contains vitamin K.^1,11

On the medicine's label

Ask your pharmacist how far apart to take them

Two groups of antibiotics, quinolones such as ciprofloxacin and levofloxacin and tetracyclines such as doxycycline, can bind to calcium, magnesium, iron or zinc, so less of the antibiotic is absorbed. The ciprofloxacin and levofloxacin labels name multivitamins among the products that can keep the antibiotic from working correctly, and NIH says zinc, calcium and magnesium supplements interact with these antibiotics.^{6,12,13,14,15,16}

On the medicine's label

Ask your pharmacist how far apart to take them

Calcium and iron can reduce how much levothyroxine is absorbed. The levothyroxine label tells patients that iron and calcium supplements can decrease its absorption, and MedlinePlus names calcium carbonate and iron supplements, and also niacin, among products that may interact with it. Many multivitamins contain calcium, and some contain iron.^3,15,17,18

On the medicine's label

Ask your pharmacist or doctor first

Methotrexate works against folate. NIH says people taking it for cancer should check with their oncologist before taking folate supplements, which include the folic acid in multivitamins, because folate could interfere with the treatment.^7,19

Expected from how the two work, not shown in studies

Do not take a multi with large amounts of beta-carotene or vitamin A if you smoke or used to smoke²
Ask first if you are pregnant, could become pregnant or are nursing
Ask first if you take warfarin, levothyroxine, an antibiotic, methotrexate or a medicine for epilepsy⁷
Ask first if you already take other vitamin or mineral supplements
Before a blood test, tell your doctor or the lab that you take a multi with biotin²⁰

Questions people ask

Do multivitamins give you energy?

Only if you were running short of something. The B vitamins in a multi help release energy from food, but more than you need does not add energy, and the sources we use do not show that a multi makes well-fed people less tired. If you feel worn out most days, see a doctor.⁴

Does a multivitamin help your skin?

The sources we use do not test multis for skin. The one skin effect they describe is a side effect: niacin in the nicotinic acid form can make the face, arms and chest flush red at 30 to 50 mg or more.⁵

What is the difference between men's and women's multivitamins?

Mainly iron. Multis made for women often have 18 mg, the full Daily Value, because women aged 19 to 50 need 18 mg a day. Men, and women over 50, need 8 mg, so their multis often have less or none.³

Is it better to get vitamins from food?

Where you can, yes. NIH and the federal dietary guidelines say most nutrients should come from food, because food also brings fiber and other components a multi does not. A multi is for the gaps.²

Can I take a multivitamin with other supplements?

Often, but add them up first. Iron, vitamin A, zinc, niacin and folic acid are the nutrients NIH names as most likely to go over their upper limits when a multi is combined with other supplements or fortified foods.²

See what we make

Every product shows its whole label and what its lab report covers. The store opens soon.

See the Full Measure line Men's Multi

Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.