Walk into any pharmacy and you’ll find shelves packed with multivitamins promising everything from “complete nutrition” to “optimal health.” The global supplement industry generates billions annually, with multivitamins sitting firmly at the top of sales charts. But here’s the thing most manufacturers won’t tell you: for the average person eating a reasonably balanced diet, these pills might be doing very little.

That’s not to say multivitamins are useless. For certain groups of people, they fill genuine nutritional gaps. For others, they’re essentially expensive urine. The trick lies in understanding which camp you fall into.

What exactly are multivitamins?

Multivitamins are supplements combining multiple vitamins and minerals in a single dose. A typical formulation includes at least 13 vitamins (A, C, D, E, K, and the eight B vitamins) plus around 16 minerals (calcium, iron, magnesium, zinc, selenium, and others).

These nutrients participate in thousands of biochemical reactions throughout your body. Some act as enzyme cofactors or hormone precursors; others serve as signalling molecules or become part of actual tissue structures like bone. When you’re short on any of them, something eventually stops working properly.

The question isn’t whether vitamins and minerals matter - they clearly do. The question is whether you need to take them in pill form.

Who actually needs multivitamins?

Current evidence doesn’t support blanket recommendations for everyone to take multivitamins. However, specific groups face higher risks of deficiency due to physiological demands or dietary restrictions.

Older adults often struggle with nutrient absorption as digestive efficiency declines with age. Vitamin B12, vitamin D, and calcium deficiencies are particularly common in this demographic. The body’s ability to convert sunlight into vitamin D also diminishes, making supplementation more relevant.

Vegetarians and vegans may lack nutrients found primarily in animal products. Vitamin B12 deficiency is almost inevitable without supplementation or fortified foods, since plant sources don’t contain bioavailable forms. Iron, zinc, and calcium can also run low depending on dietary choices.

Pregnant and breastfeeding women face dramatically increased nutrient demands. Growing a human requires substantial amounts of folate, iron, iodine, and other nutrients. Prenatal vitamins aren’t optional for this group - they’re a medical recommendation backed by strong evidence for reducing birth defects and complications.

People with malabsorption conditions like coeliac disease, Crohn’s disease, or those who’ve had bariatric surgery often can’t extract sufficient nutrients from food regardless of diet quality.

What the research says about multivitamin benefits

Let’s examine what controlled studies actually tell us. You might find some of these findings surprising.

1. Cardiovascular disease: no clear benefit

Given that heart disease remains the leading cause of death globally, researchers have devoted considerable attention to whether supplements might help. The results are underwhelming.

A systematic review of 18 clinical trials involving over 2 million participants found no association between multivitamin supplementation and cardiovascular mortality, coronary heart disease, or stroke risk [1]. Subgroup analyses looking at age, sex, smoking status, and other factors also showed no protective effects.

This shouldn’t be entirely surprising. Cardiovascular disease develops over decades through complex mechanisms involving diet, exercise, genetics, and lifestyle factors. A daily pill was always unlikely to overcome those variables.

2. Prenatal use may reduce autism risk

Here’s a more promising finding. A meta-analysis of five observational studies covering over 230,000 children found that mothers taking prenatal multivitamins had significantly lower rates of autism spectrum disorder in their offspring compared to mothers who didn’t supplement [2].

This doesn’t prove causation - women who take prenatal vitamins might differ from those who don’t in ways researchers can’t fully account for. But the association is notable enough that researchers continue investigating the connection.

3. Blood pressure regulation in certain patients

A meta-analysis of 12 randomised controlled trials with over 23,000 participants found that multivitamin supplementation reduced both systolic and diastolic blood pressure [3]. However, subgroup analysis revealed something important: the blood pressure-lowering effect only appeared in patients with existing chronic diseases or hypertension. Healthy individuals saw no benefit.

The weighted mean differences were modest: roughly 6 mmHg for systolic and 2 mmHg for diastolic pressure in the chronic disease group. That’s not nothing, but it’s nowhere near what medications achieve.

4. Cognitive function: limited effects

Who wouldn’t want a sharper memory? Unfortunately, multivitamins don’t appear to be cognitive enhancers.

A meta-analysis of 10 studies with 3,200 participants found that vitamin supplementation improved immediate free recall memory but showed no significant effects on delayed memory recall or language fluency [4]. A separate analysis of 20 studies in children suggested possible improvements in fluid intelligence and academic performance [5], though the evidence quality varied considerably.

Age-related macular degeneration destroys central vision and affects millions of older adults. Can supplements slow its progression?

A Cochrane Review of five studies with over 76,000 participants found that multivitamins don’t prevent macular degeneration from developing [6]. However, a separate Cochrane Review of 19 studies found that for people who already have the condition, supplementation may slow disease progression [7]. The AREDS and AREDS2 formulations (specific combinations of vitamins C, E, zinc, copper, and carotenoids) are the best-studied options for this purpose.

6. Breast cancer: no clear link

A Swiss population study suggested multivitamin use might increase breast cancer risk [8], which understandably caused concern. However, a larger meta-analysis of 27 studies covering 355,000 participants found no significant association in either direction [9]. Multivitamins don’t appear to cause breast cancer, but they also don’t prevent it.

7. Stress and mood improvements

A few small studies have looked at stress and mood. One double-blind trial of 50 men over 8 weeks showed improvements in stress scores and alertness [10]. Another study of 76 women over 4 weeks found improvements on the Depression, Anxiety and Stress Scale, with stress showing the biggest change [11].

The samples are tiny, and nobody knows which nutrients might be responsible. Interesting? Maybe. Actionable? Not yet.

8. Chronic fatigue syndrome

An observational study in 38 women found that multivitamin supplementation improved fatigue scores and quality of life measures [12]. Participants reported reduced sleep disturbances, fewer headaches, and increased levels of the antioxidant superoxide dismutase.

One study of 38 people doesn’t prove much, but if you’re dealing with unexplained fatigue, it’s not the worst idea to check whether you’re deficient in anything.

9. Cancer survival in malnourished patients

Malnutrition affects over 85% of cancer patients and contributes to roughly 20-40% of cancer deaths [13]. One observational study following 7,728 women with aggressive breast cancer for 7 years found that multivitamin users had 30% lower cancer mortality compared to non-users [14].

This makes intuitive sense: well-nourished bodies tolerate treatment better and fight infections more effectively. But observational studies can’t prove causation, and researchers note that multivitamin users may differ from non-users in other health-related behaviours.

10. Cataract risk reduction

Age-related cataracts are the leading cause of vision loss worldwide. A systematic review of 12 studies found that multivitamin use was associated with lower cataract risk, with longer duration of use and older age showing stronger associations [15].

11. Hip fracture prevention

Osteoporotic hip fractures carry devastating consequences: mortality rates between 20-40% within one year, and only 30-40% of survivors regaining their previous functional status.

A meta-analysis of eight observational studies with 80,000 participants found that multivitamin use was associated with significantly lower hip fracture risk [16]. However, as with other findings, observational data can’t establish that the vitamins themselves caused the protection.

Side effects and safety concerns

For healthy individuals taking standard doses, multivitamins are generally safe. The most common complaints are mild: gastrointestinal upset, constipation, or loose stools.

Allergic reactions are uncommon but can occur. Anyone experiencing rash, itching, facial swelling, dizziness, or difficulty breathing after taking a multivitamin should seek medical attention immediately.

The greater concern isn’t acute side effects but long-term excessive intake. Fat-soluble vitamins (A, D, E, K) accumulate in body tissues and can reach toxic levels with chronic high-dose supplementation. Vitamin A toxicity, for instance, can cause liver damage, bone problems, and birth defects.

Drug interactions represent another consideration. Iron interferes with the absorption of antacids, bisphosphonates, levodopa, thyroid medications, and certain antibiotics. Folic acid can reduce the effectiveness of antiepileptic drugs. Vitamin K affects blood thinners like warfarin.

Anyone taking medications should consult a healthcare provider before adding supplements.

How to choose a quality multivitamin

If you’ve determined that a multivitamin makes sense for your situation, here are three factors worth considering.

1. Check that nutrient amounts are appropriate

A quality multivitamin should contain close to 100% of the Daily Value for most vitamins and minerals. The label will list these percentages.

Calcium and magnesium are exceptions - including 100% of these bulky minerals would make pills impossibly large to swallow. Most multivitamins provide only a fraction of daily calcium and magnesium needs, which is fine if you’re getting the rest from diet.

2. Consider nutrient forms

Not all chemical forms of vitamins and minerals absorb equally well. While diving deep into biochemistry isn’t necessary, a few distinctions matter:

Nutrient	Better forms	Less ideal forms
Calcium	Calcium citrate-malate, calcium citrate	Calcium carbonate, oyster shell calcium
Magnesium	Magnesium glycinate, magnesium citrate	Magnesium oxide
Zinc	Zinc citrate, zinc picolinate, zinc gluconate	Zinc sulphate
Iron	Ferrous bisglycinate, ferrous fumarate	Ferrous sulphate (more GI upset)
Vitamin D	D3 (cholecalciferol)	D2 (ergocalciferol)
Vitamin E	D-alpha tocopherol (natural)	DL-alpha tocopherol (synthetic)

Natural forms (when available) typically absorb better than synthetic versions, though the differences vary by nutrient.

3. Avoid unnecessary additives

Manufacturing supplements requires binders, fillers, and flow agents to hold tablets together and keep production lines running smoothly. While most are harmless, some people prefer to avoid artificial colours, excessive preservatives, or ingredients they’re sensitive to. Reading labels helps identify products that align with your preferences.

The bottom line

So where does this leave us? Multivitamins sit in an awkward middle ground. The value depends entirely on your circumstances.

For pregnant women, older adults, strict vegetarians, and people with absorption issues, multivitamins fill genuine nutritional gaps. For healthy adults eating varied diets, the evidence for benefits remains weak.

What multivitamins cannot do is compensate for poor dietary choices, lack of exercise, smoking, or excessive alcohol. Those are the things that actually determine health outcomes. A daily pill doesn’t change that maths.

If you’re considering multivitamins, the honest question to ask is whether you actually need them - not whether the marketing makes you want them. Sometimes the answer is yes. Often, it’s not.

References

Jenkins DJA, et al. Supplemental Vitamins and Minerals for CVD Prevention and Treatment. J Am Coll Cardiol. 2018;71(22):2570-2584. PubMed
Li M, et al. Prenatal Micronutrient Supplementation and Risk of Autism Spectrum Disorder. Ann Epidemiol. 2019;35:1-8. PubMed
Poorolajal J, et al. Effects of Multivitamin/Mineral Supplementation on Blood Pressure. Nutr J. 2017;16(1):41. PMC
Grima NA, et al. The effects of multivitamins on cognitive performance: a systematic review and meta-analysis. J Alzheimers Dis. 2012;29(3):561-9. PubMed
Eilander A, et al. Multiple micronutrient supplementation for improving cognitive performance in children. Cochrane Database Syst Rev. 2010. PubMed
Evans JR, et al. Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration. Cochrane Database Syst Rev. 2017. PubMed
Evans JR, et al. Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration. Cochrane Database Syst Rev. 2017. PubMed
Roswall N, et al. Multivitamin Use and Breast Cancer Risk. Int J Cancer. 2010;126(4):991-7. PubMed
Chan A, et al. Multivitamin Use and Risk of Breast Cancer. Cancer Epidemiol Biomarkers Prev. 2011;20(5):846-54. PubMed
Kennedy DO, et al. Effects of high-dose B vitamin complex with vitamin C and minerals on subjective mood and performance in healthy males. Psychopharmacology. 2010;211(1):55-68. PubMed
Macpherson H, et al. Multivitamin-multimineral supplementation and mortality: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2016;103(3):881-7. PubMed
Castro-Marrero J, et al. Effect of coenzyme Q10 plus nicotinamide adenine dinucleotide supplementation on maximum heart rate after exercise testing in chronic fatigue syndrome. Clin Nutr. 2016;35(4):826-34. PubMed
Arends J, et al. ESPEN guidelines on nutrition in cancer patients. Clin Nutr. 2017;36(1):11-48. PubMed
Poole EM, et al. Postdiagnosis supplement use and breast cancer prognosis in the After Breast Cancer Pooling Project. Breast Cancer Res Treat. 2013;139(2):529-37. PubMed
Zhao LQ, et al. The effect of multivitamin/mineral supplements on age-related cataracts: a systematic review and meta-analysis. Nutrients. 2014;6(3):931-49. PubMed
Cheng L, et al. Multivitamin use and hip fracture risk: systematic review and meta-analysis. Osteoporos Int. 2021;32(5):923-933. PubMed

NHS guidance: Vitamins and minerals