Vitamins and supplements – what is worth taking
Which supplements have real evidence behind them, who actually needs one, how they interact with prescription medicines, and how to spot a product making claims it cannot keep.
Most people who eat reasonably do not need a multivitamin
Supplements are useful when there is a specific reason for one: a deficiency found on a blood test, a life stage that raises requirements, a diet that leaves something out, or a condition or medicine that interferes with absorption. Taken without a reason, a general multivitamin mostly produces expensive urine, and a few vitamins are genuinely harmful in large doses.
The ones with a clear reason behind them
- Folic acid before and during early pregnancy, to reduce the risk of neural-tube defects. Start before conception if you can, because the benefit is in the first weeks.
- Iron, when a blood test shows iron-deficiency anaemia. Iron taken without that confirmation can cause constipation and, in some conditions, harm.
- Vitamin D, for people with very little sun exposure, older adults, and some bone conditions.
- Vitamin B12, for people on long-term metformin, after certain stomach or bowel surgery, and for those eating no animal products.
- Calcium and vitamin D together, where a clinician is managing bone health.
- Specific supplements a clinician prescribes for a diagnosed condition.
Supplements used for a defined reason in South Africa:
Folic Acid — Folic Acid Lennon, Folik
Neural tube defect prevention; megaloblastic anaemia; folate supplementation in pregnancy
Ferrous Sulfate — FerroGrad, Ferrous Sulfate Lennon, Ferro-Gradumet, Fefol
Iron deficiency anaemia; iron supplementation in pregnancy
Cholecalciferol (Vitamin D3) — D-Vi-Sol, Vital D
Vitamin D deficiency; osteoporosis (with calcium); falls prevention in elderly
Cyanocobalamin (Vitamin B12) — Betolvex, Neurobion (combination)
Vitamin B12 deficiency; pernicious anaemia; neuropathy due to B12 deficiency
Zinc Sulphate — Zinplex, Zincovit
Zinc deficiency; adjunct in diarrhoea (children); wound healing; immune support
Omega-3 Fatty Acids (Fish Oil) — Omega-3, Caribsea, EPA/DHA
Hypertriglyceridaemia (adjunct); cardiovascular risk reduction; general health
Where supplements cause real harm
- Interactions. Several common supplements change how prescription medicines work, including blood thinners, epilepsy medicines, HIV treatment and thyroid medicine.
- Too much of a fat-soluble vitamin. Vitamins A, D, E and K build up in the body, and high-dose vitamin A in pregnancy can harm the baby.
- Iron overdose in children. Iron tablets look like sweets and are a leading cause of serious childhood poisoning. Keep them locked away.
- Unregistered products bought online or informally, which may contain undeclared prescription medicines.
Reading a supplement label honestly
- In South Africa, complementary medicines carry a disclaimer stating that the claims have not been evaluated by SAHPRA. That disclaimer is the most informative sentence on many packs.
- Treat any product claiming to cure, treat or prevent a serious disease as a warning sign — those claims are not permitted.
- Check whether the dose is anywhere near the recommended daily amount. Very high multiples are not automatically better and sometimes matter.
- "Natural" says nothing about safety. Several potent medicines and several poisons are plant-derived.
Common questions
- Do I need to take a multivitamin every day?
- Most people eating a reasonably varied diet do not. Supplements help where there is a specific reason — a confirmed deficiency, pregnancy, a restrictive diet, or a medicine that affects absorption.
- Can supplements interfere with my medication?
- Yes. Some affect blood thinners, epilepsy medicines, thyroid medicine and HIV treatment. List every supplement, herbal remedy and traditional medicine when you see a clinician or pharmacist.
- Are supplements regulated in South Africa?
- Complementary medicines are regulated by SAHPRA but most have not had their claims evaluated, which is why packs carry a disclaimer saying so. A product promising to cure a serious disease is making a claim it is not allowed to make.
Sources
- Medicines Online Directory and approved patient information leafletsSouth African Health Products Regulatory Authority
- Primary Healthcare Standard Treatment Guidelines and Essential Medicines ListNational Department of Health, South Africa
- Clinical and public health guidanceWorld Health Organization
Last reviewed 11 August 2026.