The daily multivitamin is bought as a hedge. Insurance against a diet you privately suspect is not quite good enough. It is the single most common supplement in the world, and for most of the people taking it, it is doing very little.
That is not the same as saying nobody should take one. There are groups for whom supplementation is genuinely important, and a few for whom it is close to essential. The problem is that those groups are not the ones the marketing targets.
What happens when you study it properly
In 2024, researchers at the US National Cancer Institute pooled three large cohorts — 390,124 generally healthy adults, followed for up to 27 years, with 164,762 deaths recorded.
Daily multivitamin users did not have a lower risk of death than non-users. Not from any cause, and not specifically from cancer, heart disease or stroke.
This is observational data and it carries the usual caveats — people who start multivitamins sometimes do so because their health is already declining, which can distort things in either direction. The authors handled that as well as the design allows. The conclusion stands: taking a multivitamin to live longer is not supported.
The US Preventive Services Task Force reached a compatible position in 2022. Insufficient evidence that multivitamins prevent cardiovascular disease or cancer — and an active recommendation against beta-carotene, which increased lung cancer risk in smokers, and against vitamin E, which showed no benefit.
Taking a shelf of supplements and not sure which ones are earning their place? Send me the list and your last blood report and I will tell you what to keep.
So who actually needs one?
This is the useful half of the article.
Anyone who could become pregnant. The strongest case in the entire supplement aisle, and it is folic acid specifically. It needs to be started before conception, because the neural tube closes in the first few weeks, often before a pregnancy is confirmed. This is not a wellness choice; it is prevention of a serious birth defect, and it is why a prenatal supplement is standard medical advice rather than marketing.
Vegetarians and vegans. Vitamin B12 is effectively absent from plant foods. This is not a debate — it is a supplementation requirement, and in India it is the single most common deficiency I see in otherwise careful eaters. Iron and zinc are worth watching too, since plant forms are absorbed less efficiently. If you are building a plant-based diet, B12 is the non-negotiable part.
Anyone on long-term metformin. It depletes B12 quietly, over years, and the tingling feet that follow get blamed on the diabetes instead.
Anyone on long-term acid-suppressing medication. Stomach acid is required to release B12 from food. Years of a proton pump inhibitor make that harder.
Older adults, for the same reason — absorption of B12 falls with age independently of diet.
After bariatric surgery, where lifelong supervised supplementation is part of the procedure, not an optional extra.
Anyone eating very little, whether through an aggressive diet, illness, or appetite loss. Below roughly 1,200 calories a day it becomes difficult to hit micronutrient requirements however well you choose.
Who needs what, and at what dose
| Group | What they actually need | Why a multivitamin falls short |
|---|---|---|
| Planning a pregnancy | Folic acid, started before conception | A general multivitamin may carry too little folate and too much retinol |
| Vegetarians and vegans | B12, reliably and lifelong | The trace dose is a top-up, not a correction |
| Long-term metformin | B12, checked and replaced | Depletion outpaces a maintenance dose |
| Long-term acid suppressants | B12, and often magnesium | Absorption is the problem, not intake |
| Menstruating women with low ferritin | A proper iron protocol | Multivitamin iron is a fraction of a treatment dose |
| Low sun exposure | Vitamin D at a corrective dose | 400 IU will not move a deficient level |
| After bariatric surgery | A supervised, specific regimen | Requirements are far above any off-the-shelf product |
Maintenance dose versus treatment dose
| Nutrient | Typical multivitamin | Typical corrective course |
|---|---|---|
| Vitamin B12 | A few micrograms | Hundreds to over a thousand micrograms, sometimes by injection |
| Vitamin D | Around 400 IU | Weekly high-dose courses prescribed and rechecked |
| Iron | A token amount | A dedicated salt, dosed and timed around food and tea |
| Folate | Maintenance level | Specific pre-conception dosing set by your doctor |
The exact figures belong to whoever is treating you. The point of the comparison is the order of magnitude: these are different categories of intervention, not different sizes of the same one.
Why a multivitamin cannot fix an actual deficiency
This is the part that costs people months.
A multivitamin carries maintenance doses — enough to top up someone who is broadly fine. A genuine deficiency needs a treatment dose of one specific nutrient, which is often ten or fifty times higher, and sometimes has to bypass the gut entirely.
Someone with a vitamin D level of 12 will not fix it with the 400 IU in a multivitamin. Someone with genuinely low B12 needs a proper replacement course, not 2.4 micrograms. Someone with iron deficiency needs an iron protocol, and the trace of iron in a multivitamin will not touch it.
Taking a multivitamin while deficient feels like doing something. It is the reason people arrive six months later with the same number on the report.
What is worth being careful about
The fat-soluble vitamins accumulate. A, D, E and K are stored rather than excreted. Taking a multivitamin plus a separate vitamin D plus a fortified drink is how people quietly stack a dose nobody intended.
Vitamin A in pregnancy. High-dose retinol is teratogenic. A prenatal supplement is formulated for this; a general multivitamin may not be.
Iron you do not need. Most multivitamins aimed at men and postmenopausal women still contain it. Iron is not a vitamin you top up casually — excess is stored, and in people with undiagnosed haemochromatosis it does real harm.
Gummies. They are sweets with a vitamin profile, they frequently contain less than the label claims because the actives degrade, and they are easy to over-consume precisely because they taste good.
If you are going to take one anyway
Plenty of people will, and that is a reasonable choice for a cheap, low-risk product. Buy it sensibly.
| Check | What good looks like |
|---|---|
| Form | Tablet or capsule, not gummies |
| Iron | Absent unless you have a reason to need it |
| Vitamin A | Mostly as beta-carotene; low retinol, especially if pregnancy is possible |
| B12 | Present and meaningful if you are vegetarian |
| Megadoses | Nothing at many multiples of requirement — more is not better here |
| Herbal extras | None. A multivitamin with a herbal blend is two products badly combined |
And take it with food. The fat-soluble vitamins need some fat present to be absorbed at all, which is why a tablet on an empty stomach at 6 am is partly wasted.
Test rather than guess
The honest alternative to a daily multivitamin is knowing your numbers. Ferritin, B12, vitamin D and thyroid between them explain most of the fatigue that sends people to the supplement shelf in the first place, and most standard health packages leave several of them out.
Correct what is actually low, at a dose that actually corrects it. Then stop.
The three mistakes I see most
Stacking without adding up. A multivitamin, a separate vitamin D, a calcium tablet and a fortified drink is four products, and nobody totals the overlap. Fat-soluble vitamins are stored, so the surplus does not simply wash out.
Treating the multivitamin as the test result. Someone feels tired, buys a multivitamin, feels no different in six weeks, and concludes nothing was wrong. What actually happened is that a maintenance dose was applied to a problem that needed measuring first.
Taking it forever without review. Requirements change. A vegetarian needs lifelong B12; someone who started a multivitamin during a stressful year two jobs ago probably does not need it now. Supplements should come up at every prescription review, and they almost never do.
What I would actually do
If you asked me to compress this into a plan: test ferritin, B12, vitamin D and thyroid once. Correct whatever is genuinely low, at a dose that corrects it, and recheck. Take B12 permanently if you are vegetarian or on long-term metformin. Take folic acid before and during early pregnancy. Beyond that, put the money into protein and vegetables, which is where the same rupees do considerably more work.
What I will not tell you
That multivitamins are harmful. For most people they are a modest, largely harmless expense — the problem is the false reassurance, not toxicity.
That food always beats supplements. It usually does, but not for B12 in a vegetarian and not for folic acid before pregnancy. Ideology is a poor guide here.
That you can tell what you are short of by how you feel. Fatigue is the final common pathway for a dozen unrelated things, several of which are not nutritional at all.
The short version
- A study of 390,000 adults over two decades found no mortality benefit from daily multivitamin use
- Guideline bodies find insufficient evidence for multivitamins in preventing heart disease or cancer, and recommend against beta-carotene and vitamin E
- Genuine cases exist: pre-conception folic acid, vegetarians and vegans needing B12, long-term metformin or acid-suppressant users, older adults, post-bariatric patients, and very low intakes
- A multivitamin carries maintenance doses and cannot correct a real deficiency — that needs a treatment dose of the specific nutrient
- Fat-soluble vitamins accumulate, and stacking multiple products is how people overdo it without noticing
- Testing ferritin, B12, vitamin D and thyroid tells you more than any daily tablet does
Before you act on any of this
I am a pharmacist and a nutritionist. I am not your doctor, and this article is general information rather than advice about you specifically. If you are pregnant or planning a pregnancy, follow your obstetrician’s advice on supplementation rather than anything written here. Nothing here is a reason to start, stop or change a prescribed medicine or a supplement your doctor has recommended. What this article can do is tell you which questions are worth asking at your next appointment.
Sources
- Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts (JAMA Network Open, 2024)
- Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer (US Preventive Services Task Force, 2022)
- Multivitamin/mineral Supplements: Fact Sheet for Health Professionals (NIH Office of Dietary Supplements)
