Iron supplements
Women aged 19 to 49 need 14.8mg of iron a day and other adults 8.7mg.
Short answer Women aged 19 to 49 need 14.8mg of iron a day and other adults 8.7mg. Do not self-treat suspected anaemia: see a GP for a blood test, because the cause needs finding and the treatment dose is far higher than a multivitamin's.
What iron does
Iron contributes to the normal formation of red blood cells and haemoglobin and to the reduction of tiredness and fatigue.
Who is most at risk
People with heavy periods, pregnant women, vegans and vegetarians, and frequent blood donors.
Taking it safely
Up to 17mg a day from supplements is unlikely to cause harm. Higher doses can cause constipation, nausea and stomach pain. Vitamin C increases absorption; tea and coffee reduce it. Keep iron tablets away from children: an overdose can be fatal.
Related pages
- Vitamins and mineralsMost people can get the vitamins and minerals they need from a varied diet.
- Pregnancy vitamins and supplementsUK advice is to take 400 micrograms of folic acid daily from before conception until 12 weeks, and 10 micrograms of vitamin D daily throughout pregnancy.
- Vitamin B12 and B complexAdults need about 1.5 micrograms of vitamin B12 a day, found almost only in animal foods.
Keep exploring
Questions people ask
How much iron do I need?
14.8mg a day for women aged 19 to 49; 8.7mg for other adults.
Can I take iron every day?
At multivitamin levels, yes; higher doses should be on medical advice.
Can I take this with medication?
Ask a pharmacist or GP first; some supplements interact with medicines.
Do supplements replace a balanced diet?
No. They are meant to add to a varied diet, not stand in for one.
Sources
- NHS: Iron (opens in a new tab)
- Great Britain nutrition and health claims register (opens in a new tab)
Checked 9 October 2026.