Do multivitamins actually work?
For most well-nourished adults, a multivitamin does not improve athletic performance, and large trials show little or no effect on heart disease, cancer or death. It does help specific groups: people on restrictive diets, vegans needing B12, pregnant women and some older adults, where the COSMOS trial found a small memory benefit. In South Africa, your diet matters more than the brand.
- A meta-analysis of 21 trials found multivitamins had no effect on all-cause, heart disease or cancer mortality (NIH ODS summary).
- COSMOS (about 21 000 adults, median 3.6 years) found no reduction in cancer or cardiovascular events.
- COSMOS ancillary studies found improved global cognition and episodic memory in older adults, which needs confirmation.
- The AIS lists multivitamins in Group B (emerging evidence).
- South African multivitamins cost about R3 to R18 a day as of October 2026.
What do the big trials show?
The NIH Office of Dietary Supplements summarises the research plainly: multivitamin and mineral products do not reliably reduce chronic disease risk or mortality.
| Outcome | What trials found | Evidence level |
|---|---|---|
| Death from any cause, heart disease or cancer | A meta-analysis of 21 trials found no effect | Weak for benefit |
| Cancer | Physicians' Health Study II found an 8% drop, but not for any single cancer or for cancer deaths | Weak, mixed |
| Heart events | No reduction in major cardiovascular events | Weak for benefit |
| Memory in older adults | COSMOS ancillary studies (about 5 000 people, mean age 69 to 73) found better global cognition and episodic memory | Emerging, needs confirmation |
The main COSMOS trial followed about 21 000 adults for a median of 3.6 years and found no reduction in total invasive cancer or cardiovascular events.
Who is most likely to benefit?
- People on restricted or low-energy diets, including some weight-loss diets, where whole food cannot supply every micronutrient.
- Vegans, mainly for vitamin B12 (how much B12 vegans need).
- Pregnancy and planning pregnancy, using a prenatal formula with folic acid, not a standard multivitamin.
- Older adults, where B12 absorption from food declines and the COSMOS memory signal is of interest.
- People with conditions that impair absorption, under medical supervision.
Do multivitamins help athletes?
Not for performance in well-fed athletes. The AIS classes multivitamins in Group B, meaning emerging evidence and use under a protocol. A multivitamin is also a weak tool for a real deficiency: a typical product carries 200 to 400 IU of vitamin D and 1 to 10 mg of iron, so a runner with low ferritin needs testing and targeted treatment, not a multi (see iron for runners). If you are drug-tested, remember that SAIDS applies strict liability to everything you swallow, and no multivitamin sold in South Africa is endorsed by SAIDS.
Are there downsides?
At about 100% of daily needs, risk is low. The concerns are megadoses and stacking:
- Smokers should avoid products with large amounts of beta-carotene or vitamin A, which were linked to more lung cancer in trials.
- Excess preformed vitamin A in pregnancy can increase the risk of birth defects.
- Warfarin users should speak to their doctor before taking anything containing vitamin K.
- Iron-containing products must be stored away from young children.
What does this mean in rand?
As of October 2026, a South African multivitamin costs roughly R3 to R18 a day (Dis-Chem Living Fit and Faithful to Nature). If your diet is varied and you eat protein, vegetables, fruit and dairy or fortified alternatives, the same money is usually better spent on food. If you do choose one, compare label doses in our multivitamin guide, see the ranking on our best multivitamin page and read which vitamins athletes actually need. A multivitamin cannot compensate for a poor diet, and it does not give you energy.
Products mentioned, with dated prices
| Product | Size | Price | Servings | R per serving | Sweeteners |
|---|---|---|---|---|---|
| Dis-Chem Gold Multivitamin Supreme Active 60 softgels | 60 softgels | R200Dis-Chem Living Fit, Oct 2026 | 60 | R3.33 | glycerol (132 mg sugar source per capsule) |
| Viridian High Five Multivitamin and Mineral 90 capsules | 90 capsules | R675Faithful to Nature, Oct 2026 | 90 | R7.50 | none |
Compare the options
- Best Magnesium Supplement in South Africa 2026: 7 Products Compared
- Best Omega-3 Fish Oil in South Africa 2026: 9 Products Compared
- Best Multivitamin in South Africa 2026: 7 Products Compared
Related questions
- What is the best multivitamin in South Africa?
- How much vitamin B12 do vegans need in South Africa?
- Can you overdose on vitamins and minerals?
- Which vitamins and minerals do athletes actually need in South Africa?
- What is the best multivitamin for over 50s in South Africa?
Sources
- NIH Office of Dietary Supplements: Multivitamin/mineral supplements, health professional fact sheet
- COSMOS trial: multivitamin supplementation and cognitive function in older adults (Am J Clin Nutr 2024, PubMed)
- Australian Institute of Sport Supplement Framework, Group B
- SAIDS (South African Institute for Drug-Free Sport) FAQ: supplements, strict liability, medication check
Educational information only, not medical advice. Speak to a doctor, pharmacist or registered dietitian before using supplements if you are pregnant or breastfeeding, under 18, taking medication, or living with kidney, liver or heart disease.
Cite this page: Healthnews24, “Do multivitamins actually work?”, updated 27 October 2026, https://www.healthnews24.co.za/answers/do-multivitamins-work/. Plain-text version: /answers/do-multivitamins-work.md