How to Choose a Multivitamin: A Label-Reading Guide Without Brands

Nutrition · Published 2026-10-24

White capsules spilling out of an unlabelled white bottle — Capsules spilling from an unlabelled bottle.

Shelves and online shops offer hundreds of multivitamins, each promising something. Choosing well is less about finding the "best" product than about knowing what you need, what to avoid, and how to read a label. This guide names no brands and recommends no products.

Step 1: ask whether you need one at all

Large trials in healthy, well-nourished adults have not shown that multivitamins prevent heart disease or extend life (see do multivitamins work?). Official advice targets specific nutrients for specific groups: folic acid before and in early pregnancy, vitamin D in winter or with little sun, vitamin B12 for vegans and many older adults. If one of those is your only need, a single-nutrient supplement may be simpler than a multivitamin. A doctor, pharmacist or dietitian can help you decide; see who may need supplements.

A multivitamin can make sense when several needs overlap (for example, a vegan who also wants vitamin D and iodine), when appetite or diet is limited, or after medical advice such as following weight-loss surgery, where specific formulations are prescribed.

Step 2: read the label like a pharmacist

Ignore the front of the pack and turn to the panel listing the nutrients: "Supplement Facts" in the US, a nutrition table with "% NRV" in the EU and UK.

Amount per serving. Check the serving size: some products require two or more tablets or gummies a day to deliver the amounts listed.
%DV or %NRV. These compare each amount to a single reference figure. Percentages around 100% are typical; very high percentages (several hundred or thousand percent) are a signal to check upper limits. Remember that the EU NRV for vitamin D (5 mcg) is lower than current advice, so a percentage over 100% for vitamin D on a European label is normal. See how to read reference intakes.
Units. Vitamin D may be given in micrograms or IU (1 mcg = 40 IU); folate in mcg DFE on US labels; vitamin A in mcg RAE.

Step 3: check the nutrients that need care

Nutrient	What to check
Iron	Many adult men and postmenopausal women do not need supplemental iron, and the NIH ODS notes that formulas for these groups often contain little or none. Iron is dangerous for young children: keep any iron-containing product out of reach. People with haemochromatosis should avoid it.
Vitamin A	Check whether it is preformed (retinol, retinyl acetate or palmitate) or beta-carotene. In pregnancy, avoid supplements with retinol unless prescribed; pregnancy-specific formulas are designed for this. Smokers and former smokers should avoid high-dose beta-carotene, which raised lung cancer risk in trials.
Vitamin B6	EFSA lowered its adult upper limit to 12 mg a day in 2023 because of nerve damage reports. Many products contain more; add up B6 from all supplements you take.
Folic acid	The adult upper limit for folic acid is 1,000 mcg a day. Pregnancy planning usually calls for 400 mcg (higher doses only on prescription).
Vitamin D	The adult upper limit is 100 mcg (4,000 IU) a day. Check whether you also take a separate vitamin D product.
Vitamin K	Can reduce the effect of warfarin. People on warfarin should discuss any multivitamin with their anticoagulation clinic or pharmacist.
Zinc, selenium, iodine	Useful in normal amounts, harmful at high doses over time; compare with the upper limits.

The simplest rule: a general multivitamin should provide nutrients at around the reference intake, not megadoses. Stacking several products is the most common way people exceed upper limits.

Step 4: match the formula to your life stage

Planning a pregnancy or pregnant: a pregnancy-specific product with 400 mcg folic acid and 10 mcg vitamin D (NHS advice), without retinol. Ask your midwife or doctor.
Vegan: check for vitamin B12, vitamin D, iodine and possibly calcium. See vitamin B12 and iodine.
Over 50: B12 in supplement form is absorbed even when stomach acid is low; vitamin D needs rise after 70 in US guidance; iron is often unnecessary.
Children: use only products made for the child's age; the NHS recommends vitamins A, C and D for children aged six months to five years, not general adult multivitamins.

Step 5: look for independent quality testing

Supplements are not licensed medicines. In the United States they do not need FDA approval for safety or effectiveness before going on sale, though manufacturers must follow good manufacturing practice rules. In the EU and UK they are regulated as foods: the nutrients and forms allowed are listed, and health claims must come from an authorised list, but products are not tested by regulators before sale.

Independent certification programmes help with quality, not with whether you need the product:

USP Verified (United States Pharmacopeia): checks that a product contains the listed ingredients in the declared amounts, does not contain specified harmful levels of contaminants, will break down and release ingredients in the body, and was made under good manufacturing practices.
NSF/ANSI 173 certification (NSF): tests that label contents match, screens for contaminants and audits manufacturing. "NSF Certified for Sport" adds screening for substances banned in sport, relevant to athletes subject to drug testing.

A certification mark should be verifiable on the certifier's own website. Absence of a mark does not mean a product is poor, but presence of a verified one reduces uncertainty about what is in the bottle.

Step 6: be sceptical of marketing claims

"Whole food", "natural" or "food-based" vitamins are not shown to be more effective for most nutrients; some synthetic forms (folic acid, B12) are better absorbed than food forms.
Methylfolate for "MTHFR" variants: the US CDC states that people with common MTHFR variants can process folic acid, and recommends folic acid for neural tube defect prevention regardless of MTHFR status.
Gummies often contain sugar, may provide fewer nutrients (many lack iron), and appeal to children, increasing the risk of accidental overdose.
"Energy", "immunity" or "detox" claims do not mean the product does more than a standard formula; in the EU and UK, only authorised wording such as "vitamin C contributes to the normal function of the immune system" is permitted, and it applies to any product with enough vitamin C.
Price is not a reliable guide to quality.

Step 7: tell your pharmacist

Mention every supplement you take when you get a prescription or buy medicines. Calcium, iron, magnesium and zinc can reduce the absorption of thyroid medicine and some antibiotics; vitamin K affects warfarin. Store supplements as labelled, respect the use-by date, and keep them away from children.

In short

First decide whether you need a multivitamin, or just one specific nutrient.
Choose amounts around reference intakes, not megadoses, and add up what you get from all products.
Watch iron, vitamin A, B6, vitamin D, folic acid and vitamin K.
Independent marks such as USP Verified or NSF certification indicate quality, not need.

This page is general information, not medical advice, and does not recommend any product. Ask a pharmacist, doctor or registered dietitian before starting a supplement, particularly if you are pregnant, take medication or have a long-term condition.