How to choose a multivitamin: read the label first

There is no single best multivitamin. There is one that fits what you need and one that does not, and the label is the only place you can tell them apart. If you want the short version: look for doses close to the NRV (the nutrient reference value printed on European labels), avoid megadoses, be wary of long lists of herbs and botanicals, and prefer a product that has been tested by an independent body. A higher price is not a quality signal. The Harvard T.H. Chan School of Public Health notes that generic store brands can deliver the same results as premium ones.

That same source also makes a point worth sitting with: for people who already eat a varied, balanced diet, a multivitamin may offer little or no benefit. That is not an argument against supplements. It is an argument for buying with your eyes open, especially since the shelf is crowded and the label is rarely clear.

What actually separates one multivitamin from another

Most multivitamins contain around 26 vitamins and minerals, and many supply 100% of the recommended daily amount of each. That is the pattern Harvard describes. The average hides enormous variation between products, though.

What changes from bottle to bottle? Which nutrients are included, the chemical form of each one, how much is in a serving, and how many tablets or gummies count as that serving. Extras matter too — plant extracts, for instance — and so does whether the product has been independently tested. In practice the label is your only comparison tool, and it is where most people get lost.

How to read the label without getting lost in the table

Start with the percentage of the NRV per serving. In the European Union, Directive 2002/46/EC sets a harmonised list of vitamins and minerals and of the sources permitted in food supplements, precisely to protect consumers and prevent misleading information. Nutrients on a label are therefore authorised ones — but that says nothing about whether two products are equivalent.

A product declaring 100% of the NRV for most nutrients is in line with what Harvard describes as typical. A product declaring 1000% of the NRV for one vitamin and 10% for another is making an editorial choice. It may be deliberate. You still have the right to know why.

Next, check the serving. Nutrition information always refers to a specific serving, which might be one tablet, two gummies or three capsules. If the label says "per 2 gummies", that is the number that counts. Comparing products without accounting for this is comparing different things.

What to avoid in the table

Megadoses — many times the recommended daily amount — are not advisable. Harvard explains why: they can interfere with the absorption of other nutrients or of medicines, or become toxic if taken in excess over long periods. If a product boasts doses far above what the body needs, ask yourself who benefits.

Be cautious, too, with products carrying a long list of herbs and botanicals. The same source warns that these extras usually have no research behind them on long-term effects. That does not make them dangerous. It does mean you do not know what you are taking together.

The label promises you should ignore

"Supports brain health", "boosts energy", "improves skin and hair". Harvard advises treating this kind of wording with suspicion. It is marketing, not an authorised health claim, and it tells you nothing about what is actually in the bottle.

The pull towards the most expensive bottle because it promises more is understandable. Price is not an indicator of quality, though. A store brand can carry the same nutrient, in the same form, at the same dose. What differs is the packaging and the marketing.

Independent testing: the seal worth looking for

Harvard recommends looking for a multivitamin that contains the recommended amounts and carries the United States Pharmacopeia (USP) seal. That seal confirms that the ingredients and amounts listed on the label are really in the product, and that it has been tested for contaminants such as heavy metals and pesticides.

You can look for information about independent testing on the manufacturer's website or ask directly. If a brand gives you nothing at all about quality control, that is already an answer.

Do not confuse "tested" with "certified". The right question is: tested for what, and by whom?

What the evidence does not let anyone claim

The US Preventive Services Task Force concluded in 2022 that evidence is insufficient to assess the balance of benefits and harms of multivitamins for preventing cardiovascular disease or cancer in non-pregnant, community-dwelling adults. That does not mean they do nothing. It means nobody knows for certain whether they do anything in those contexts.

So be sceptical of anyone promising you specific results. A multivitamin does not replace a varied, balanced diet or a healthy lifestyle. If you suspect a specific deficiency, the route is a test and the opinion of a healthcare professional — not a bottle bought on impulse.

Who should take care before buying

Some medicines can affect nutrient levels. Harvard gives two examples: certain diuretics can deplete magnesium, potassium and calcium, and proton pump inhibitors can block the absorption of vitamin B12. If you take medication, always tell your doctor about every supplement you use, because of possible interactions.

Pregnant and breastfeeding women, and people with chronic conditions, should speak to a healthcare professional before starting any supplement. This is not a formality. It is the difference between supplementing safely and supplementing blind.

There are also upper intake levels you should not exceed. EFSA defines the tolerable upper intake level (UL) as the maximum total chronic daily intake of a nutrient from all sources that is not expected to pose a risk of adverse health effects. For adults, EFSA gives, for example, 100 µg/day for vitamin D, 25 mg/day for zinc and 255 µg/day for selenium. These figures are useful for comparing products: if a multivitamin approaches or exceeds the UL for a nutrient, that is a sign you may be getting more than you need.

A worked example: the Multivitamin Gummies label

TuttiBear's Multivitamin Gummies declare, per 2-gummy serving, among other things: Vitamin C 20 mg (25% NRV), Vitamin D 50 µg (1000% NRV), Vitamin E 4.5 mg (38% NRV), Riboflavin 0.4 mg (29% NRV), Vitamin B6 2 mg (143% NRV), Folic Acid 10 µg, Vitamin B12 8 µg (320% NRV), Biotin 180 µg (360% NRV), Pantothenic Acid 2 mg (33% NRV), Zinc 3 mg (30% NRV), Omega-3 Fatty Acids (Chia Seed Extract) 1 mg, and a blend of glycine, glutamic acid and L-glutathione 100 mg.

Note that vitamin D sits at 1000% of the NRV, which means one daily serving of this product already supplies ten times the reference amount. It is not a megadose in Harvard's sense, but it is a quantity worth factoring in if you take other supplements containing vitamin D. The same reasoning applies to B12 and biotin, both above 300% of the NRV.

The recommended dose is 2 gummies a day. Do not exceed the recommended daily dose. The product is intended for adults and contains polyols; excessive consumption may have a laxative effect. Keep out of reach of young children. In case of pregnancy, breastfeeding, illness or use of medication, consult a healthcare professional before consuming.

None of this is a recommendation to buy. It is an example of how to read a label: identify the serving, compare each nutrient against the NRV, check whether any nutrient exceeds the UL, and read the warnings. The same exercise works on any brand.

Questions to ask before you pay

• What is the daily serving, and how many nutrients sit above 100% of the NRV?
• Does any nutrient exceed EFSA's tolerable upper intake level for adults?
• Does the product have third-party testing, or a seal confirming its contents and the absence of contaminants?
• Does the label promise specific benefits (brain, energy, skin, hair)? If so, be sceptical.
• Does it contain herbs or botanicals with no long-term research?
• Do you take any medicine that could interact with vitamins or minerals? If yes, speak to your doctor or pharmacist before buying.

There is no magic number of nutrients that makes one product better. There is a set of checks that helps you rule out the ones that do not suit you. And if you conclude you do not need a multivitamin, that is a perfectly good decision too. Harvard says the benefit may be nil for people who eat well. Knowing that is more useful than any claim on a label.