Verified Supplement Data

Best Time to Take Iron

Take iron in the morning on an empty stomach, once a day or every other day. That means 30 minutes before eating, or 2 hours after (NHS); food can cut absorption by up to 75%. Keep tea, coffee, calcium and thyroid medicine 2 hours or more away.

By Erin Rose Updated October 6, 2026 How we score

When to take it, and what to keep away

  1. Morning, on an empty stomach: 30 minutes before eating, or 2 hours after

    UK guidelines say iron is best taken fasting first thing in the morning, or between meals (BSG 2021). The NHS puts it in hours: 30 minutes before eating, or 2 hours after.

  2. Once a day at most; every other day is fine

    Iron raises hepcidin, a hormone that lowers how much of the next dose is absorbed. A 60 mg dose every other day was absorbed better than daily (Stoffel 2017), and caused fewer stomach side effects with the same gain in stores (von Siebenthal 2023). US guidelines say once a day at most (AGA 2024).

  3. Not with a meal, if you can manage it

    Taking iron with meals can cut absorption by up to 75% (BSG 2021). If it upsets your stomach, a small snack is better than skipping it.

  4. Tea and coffee 2 hours apart

    The NHS advises a 2-hour gap between iron and tea, coffee, eggs or dairy. In a study of iron from meals, a cup of coffee cut absorption by 39% and tea by 64% (Morck 1983).

  5. At a different time from calcium

    Calcium might interfere with iron absorption; experts advise taking the two at different times (NIH). That includes calcium supplements and calcium antacids.

  6. Hours apart from thyroid medicine and levodopa

    Iron can make levothyroxine and levodopa work less well (NIH). Ask your pharmacist how far apart.

All the iron we score · How much to take

Every day or every other day?

Either works. Every other day may let more of each dose in. After an iron dose, the body raises hepcidin, a hormone that limits how much iron the gut takes in for about a day. In iron-depleted women, a 60 mg dose every other day was absorbed better than the same dose daily (Stoffel 2017). In a 6-month trial, every-other-day iron gave the same gain in iron stores as daily iron, with fewer stomach side effects and less iron deficiency at the end (von Siebenthal 2023). UK guidelines suggest every other day when a daily tablet is not tolerated (BSG 2021).

With food or without?

Without, if you can. Tea, coffee and the phytate in whole grains and beans lower iron absorption, and calcium might too (BSG 2021; Morck 1983; NIH), and taking iron with meals can cut absorption by up to 75% (BSG 2021). The catch is the stomach: iron on an empty stomach upsets some people. If it does, a small snack is better than stopping. Taking it every other day may help too.

Vitamin C: the guidelines disagree

A 2024 US guideline for doctors says to add vitamin C to oral iron (AGA 2024). The 2021 UK guideline does not recommend it, because a large randomized trial found vitamin C neither improved the response to iron nor reduced side effects (BSG 2021). A 2023 review found no clear benefit, with very low-quality evidence (Loganathan 2023). A glass of orange juice does no harm; you do not need to pay extra for iron with vitamin C added.

Questions

Is it better to take iron in the morning or at night?

The morning, on an empty stomach, if you can. UK guidelines advise a fasting dose first thing in the morning or between meals (BSG 2021), and the absorption trials gave iron in the morning (Stoffel 2017). If night is the only time you will remember, take it then, away from dinner.

Should I take iron with vitamin C?

Guidelines disagree. A US guideline for doctors says to add it (AGA 2024). The UK guideline does not recommend it, because a large randomized trial found it neither improved the response nor reduced side effects (BSG 2021). It does no harm, but you do not need a product with vitamin C added.

Can I take iron with coffee?

Not together. The NHS advises leaving 2 hours between iron and coffee or tea. In a study of iron from meals, a cup of coffee cut absorption by 39% (Morck 1983).

Can I take iron and a multivitamin together?

Check the label. If your multivitamin has calcium, take it at a different time from your iron; calcium might interfere with iron absorption (NIH).

What if iron upsets my stomach?

Take it every other day, or with a small snack. Every-other-day iron caused fewer stomach side effects in a trial of iron-depleted women (von Siebenthal 2023). If it still does, try a gentler form such as bisglycinate.

Sources

  1. Snook J, et al. British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults. Gut. 2021. PubMed 34497146; full text PMC8515119, read October 6, 2026.
  2. DeLoughery TG, et al. AGA Clinical Practice Update on Management of Iron Deficiency Anemia. Clin Gastroenterol Hepatol. 2024. PubMed 38864796
  3. Stoffel NU, et al. Lancet Haematol. 2017. PubMed 29032957
  4. von Siebenthal HK, et al. EClinicalMedicine. 2023. PubMed 38021373
  5. Morck TA, Lynch SR, Cook JD. Inhibition of food iron absorption by coffee. Am J Clin Nutr. 1983. PubMed 6402915
  6. Loganathan V, et al. Clin Nutr ESPEN. 2023. PubMed 37739692
  7. NHS. How and when to take ferrous sulfate (last reviewed February 9, 2023; read October 6, 2026).
  8. NIH Office of Dietary Supplements. Iron fact sheet for health professionals (updated September 4, 2025; read October 6, 2026).