The short answer
For most well-fed adults, a supplement is hard to justify: the largest trial reviews found little or no benefit from vitamins and minerals in people without a known deficiency. Yet health bodies tell specific groups to take one specific nutrient, such as vitamin D in winter. Both are true, because they answer different questions.
Do supplements work for healthy adults?
For healthy adults, the evidence for general use is weak. The 2022 evidence report for the US Preventive Services Task Force covered adults without known deficiencies and found little or no benefit on cancer, heart and circulation disease or death from any cause. The Task Force called the evidence on multivitamins insufficient.1,3
Two numbers show the scale. Across 27 trials with 117,082 people, vitamin D showed no clear effect on death from any cause (odds ratio 0.96). Across 9 trials with 107,772 people, vitamin E showed none either (odds ratio 1.02).1 A 2013 review of 24 studies with 324,653 nutrient-sufficient adults found no clear evidence of benefit or harm from single and paired nutrients.2
These reviews did not study people with a deficiency. That limit matters, as the next sections show.
Why does research on supplements look so disappointing?
Three structural reasons explain why trial results look flat, and none of them means supplements are useless for everyone. First, trials mostly recruit people who already have enough of the nutrient being tested, so there is no gap for the supplement to fill. Second, supplement users are healthier to begin with, which distorts observational comparisons. Third, a trial reports an average effect across very large groups of people, which is not the same as an answer for you as an individual.
Do trials study people who already have enough?
Mostly, yes. The 2022 review included only adults with no known vitamin or mineral deficiencies.1 If nearly everyone in a trial already gets enough from food, adding more can show very little. That result does not tell you what a person with a real gap would gain, because the trial never asked.
Are supplement users healthier to begin with?
Yes, on average. In the German EPIC-Heidelberg cohort, regular supplement use was reported by 47% of women and 41% of men, and users of vitamins or minerals were more often non-smokers or ex-smokers, leaner, more active and better educated.6 A 2025 Portuguese study of 1,122 adults found that users often kept healthier lifestyles already.5 So when users look healthier in a survey, much of that health arrived with them.
Does a trial average say anything about you?
Only in part. A pooled odds ratio from tens of thousands of people tells you what happened on average. It does not tell you what happens to one person. Your diet, age, skin colour and time outdoors decide whether you resemble the people in that trial.
Why do official bodies still recommend some supplements?
Official bodies answer a different question. A prevention trial tests one pill across a broad group of people. Official advice asks whether one nutrient closes one known gap in one group. The NHS advises everyone to consider 10 micrograms of vitamin D a day in autumn and winter, because between October and early March we do not make enough from sunlight.8
The Dutch Voedingscentrum says most people do not need supplements, then names the exceptions: pregnant women (folic acid and vitamin D), young children (vitamin D) and older people (vitamin D).11 Vegans are another clear case. Vitamin B12 is not found naturally in fruit, vegetables or grains,10 and a 2024 meta-analysis found lower serum B12 in adult vegans than in omnivores.4 Advice differs per country, so check the guidance where you live.
Who has an official reason to take a supplement?
Five situations come up in the official advice we read: everyone in winter (NHS), people rarely outdoors or with dark skin (NHS), pregnancy and planning a pregnancy, young children and older people, and vegans. For doses in pregnancy, ask a midwife, doctor or pharmacist.
| Group | Nutrient | Whose advice | What the advice does not cover |
|---|---|---|---|
| Everyone, autumn and winter | Vitamin D, 10 µg a day | NHS (UK) | April to September, when most people can make enough from sunlight |
| People rarely outdoors, or with dark skin | Vitamin D, 10 µg a day all year | NHS (UK) | Any other nutrient |
| Planning a pregnancy, first 12 weeks of pregnancy | Folic acid | NHS (UK),9 Voedingscentrum (NL)11 | Who needs a higher dose: ask a midwife, doctor or pharmacist |
| Pregnant women, young children, older people | Vitamin D | Voedingscentrum (NL) | General multivitamins |
| Vegans | Vitamin B12 | NHS (UK) | A fixed supplement dose: the NHS names a need of about 1.5 µg a day for adults |
Does a general multivitamin hold what the advice asks for? Not always. A UK survey of 67 children's multivitamins found that only 25% to 36% of them, depending on the child's age, gave at least 400 IU of vitamin D a day.7
Who is unlikely to gain from a supplement?
An adult who eats a varied diet, has no known deficiency and fits none of the groups above has no official reason to buy a supplement, and that includes buying from us. The NHS says most people should get all the nutrients they need from a varied and balanced diet,12 and the Voedingscentrum says the same.11
Where diet can fall short, nutrient by nutrient, is covered in can you get everything from food alone.
Is a multivitamin a waste of money?
A multivitamin bought as general insurance is hard to defend: the Task Force found the evidence insufficient.3 In a US survey, 31% of adults had used a multivitamin in the prior 30 days,3 so it is a common habit. A common habit is not evidence that it works.
If you have one known gap, buy for that gap. The children's survey above shows why: a general product may hold less of the nutrient you came for.7 A single-nutrient product is often the simpler choice, and it need not be the expensive one. Why prices differ so much is explained in why two supplements with the same nutrient can cost so differently.
Can a supplement do harm?
Yes, and beta carotene is the clearest example. In the 2022 pooled analysis of adults without known deficiencies, beta carotene with or without vitamin A was linked to more lung cancer (odds ratio 1.20, 4 trials, 94,830 people).1 The Task Force recommends against beta carotene and vitamin E supplements for prevention.3 More is not automatically better.
The NHS warns that too much vitamin D over a long period can cause too much calcium to build up in the body.8 The Voedingscentrum says large amounts of vitamins, minerals or bioactive substances can be harmful with long-term use.11 At EU level there are no binding maximum levels for supplement ingredients, according to EFSA, so the dose on a label is no proof of safety.13 A food supplement is not a substitute for a varied, balanced diet.
How do you decide if a supplement is worth it for you?
Ask four questions before you buy. Is there official advice for your group? Do you have evidence of a personal gap, from your diet or a blood test? Does the product hold the nutrient and amount that the advice names? And does it fit within what you already get from food and fortified products?
For the second question, our guide to which blood markers are worth checking before you supplement explains what a test can and cannot show.
How does our own range pass this test?
Our range passes on labelling and fails on fit for several groups, so here are the limits. Our vitamin D3 + K2 drops give 125 µg of vitamin D3 per 0.25 ml serving, once every 3 days. By our own calculation that averages about 42 µg a day, about four times the 10 µg in the NHS advice, so this is not the NHS dose. It is not intended for pregnant or breastfeeding women, and anyone taking anticoagulants (blood thinners) should consult a physician first. Vitamin D contributes to the maintenance of normal bones and to the normal function of the immune system.
Our vitamin B complex holds all eight B vitamins plus choline and inositol, including 500 µg of vitamin B12 as methylcobalamin. That is far above the 1.5 µg a day the NHS names as the adult need. It is not recommended during pregnancy or breastfeeding, or for those under 18, without medical advice. Vitamin B12 contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.
We sell no folic acid product for pregnancy and no iron product. If you are in that group, ask a pharmacist or midwife and buy elsewhere.
Frequently Asked Questions
Do supplements actually do anything?
It depends on your starting point. Official bodies name specific groups because food or sunlight leaves a known gap there.8,11 For well-fed adults without a deficiency, the large reviews found little or no benefit.1
Is a daily multivitamin a waste of money?
For most well-fed adults, it is hard to justify. The US Task Force found the evidence on multivitamins insufficient.3 Insufficient means the question is open, which is different from proven useless.
Why does the NHS still recommend vitamin D?
Because between October and early March, people in the UK do not make enough vitamin D from sunlight, so the NHS says everyone should consider 10 µg a day in autumn and winter.8 That is advice about one nutrient and one season, not a general case for supplements.
Can I just eat well instead of taking supplements?
For most people, yes. That is the position of both the NHS and the Voedingscentrum.11,12 The exceptions are the groups in the table above.
Are higher doses better than the recommended amount?
No. Beta carotene is the example of more going wrong,1 and the NHS warns about too much vitamin D over a long period.8 Match the amount to your reason for taking it, and do not exceed the dose on the label.
The Bottom Line
Most well-fed adults have no official reason to take a supplement, and the large reviews support that restraint.1 Specific groups have specific advice: vitamin D in the darker months, folic acid around pregnancy, B12 for vegans. Find your group, check what the product holds, and keep your money when there is no reason to spend it. We apply that test to our own range too.
Sources
- Vitamin and Mineral Supplements for the Primary Prevention of Cardiovascular Disease and Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force, JAMA, 2022
- Vitamin and mineral supplements in the primary prevention of cardiovascular disease and cancer: An updated systematic evidence review for the U.S. Preventive Services Task Force, Annals of Internal Medicine, 2013
- Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement, JAMA, 2022
- A systematic review and meta-analysis of functional vitamin B12 status among adult vegans, Nutrition Bulletin, 2024
- Exploring the Lifestyle and Dietary Patterns of Food Supplement and Non-Food Supplement Users: A Cross-Sectional Study in the Portuguese Population, Nutrients, 2025
- Lifestyle and diet in people using dietary supplements: a German cohort study, European Journal of Nutrition, 2007
- Vitamin D supplementation: are multivitamins sufficient?, Archives of Disease in Childhood, 2020
- Vitamin D, NHS
- Folic acid, NHS
- B vitamins and folic acid, NHS
- Voedingssupplementen, Voedingscentrum
- Vitamins and minerals, NHS
- Food supplements, European Food Safety Authority
- Regulation (EU) No 432/2012, EUR-Lex
