Iron deficiency is very common in perimenopause, the treatment is cheap and effective, and a large number of women give up within a fortnight because the tablets make them feel awful. Most of that is avoidable — the standard advice on how to take iron has changed, and the newer approach is both better tolerated and better absorbed.

Where we stand: Menova is an independent publication. We sell no supplements, we are not your doctor, and this is general education, not medical advice or a dose recommendation. Do not take iron without a confirmed deficiency — excess iron is harmful.

Get tested first

Iron is not a supplement to take speculatively. Excess iron accumulates and causes harm, and some people have haemochromatosis without knowing.

Ask for ferritin, not just a full blood count. Ferritin falls before haemoglobin does, so you can be genuinely deficient and exhausted with a "normal" blood count. Ranges are wide at the bottom, and many women feel unwell at levels technically inside them — see low ferritin in perimenopause and reading your own blood test results.

Ferritin also rises with inflammation, so a normal result alongside raised inflammatory markers can be misleading.

The change worth knowing about

Traditional advice was several doses a day. Research on iron absorption changed that.

Taking iron raises hepcidin, a hormone that blocks further absorption for around 24 hours. So a second dose the same day is largely wasted — and it delivers all the side effects.

Current thinking, increasingly reflected in practice:

  • One dose a day, or
  • Alternate days, which studies suggest can achieve equal or better total absorption with fewer side effects

Alternate-day dosing is the single most useful thing in this article. If tablets are making you miserable, ask your clinician whether every other day would suit you. It is often as effective and much easier to continue.

Taking it well

  • On an empty stomach absorbs best — but if that makes you nauseated, taking it with a little food is far better than not taking it at all
  • With vitamin C. Orange juice or a vitamin C tablet meaningfully improves absorption of non-haem iron
  • Away from tea and coffee by about an hour — the tannins substantially reduce absorption. Morning tea with a morning iron tablet is a common self-defeating combination; see caffeine in menopause
  • Away from calcium by a couple of hours — including dairy and calcium supplements
  • Away from levothyroxine by four hours — see HRT and thyroid medication
  • Away from antacids and proton pump inhibitors, which reduce the stomach acid iron needs

Managing the side effects

Constipation, nausea, stomach pain and dark stools are the usual complaints. Dark or black stools are expected and harmless.

  • Try alternate days first. This resolves it for many people
  • Take it in the evening if nausea is the issue
  • Change the salt. Ferrous sulfate, fumarate and gluconate differ in tolerability. If one is unbearable, ask about another — gluconate is often gentler
  • Liquid iron allows smaller doses and suits some people better
  • Fibre and fluid for the constipation, and a stool softener if needed
  • Do not double up after a missed dose

Keep iron out of reach of children. Iron overdose is a leading cause of poisoning deaths in young children, and this is not widely known.

How long it takes

  • Energy often improves within two to four weeks
  • Haemoglobin typically corrects within about two to three months
  • Ferritin stores take considerably longer — commonly three to six months of continued treatment after the blood count normalises

That last point is where most people go wrong: stopping when they feel better refills nothing, and the deficiency returns. Ask what your target ferritin is and when to retest.

When tablets are not the answer

  • Severe deficiency, or intolerance to all oral forms — iron infusion is an option, corrects stores quickly, and is under-offered. Worth asking about if you have been struggling for months
  • Malabsorption — coeliac disease is a classic missed cause, and worth screening for in unexplained iron deficiency
  • Ongoing heavy blood loss. Supplementing while losing the same amount monthly is bailing out a boat with a hole in it

Fix the cause, not just the number

This is what turns a recurring problem into a solved one.

Heavy periods are the usual cause in perimenopause, and they are treatable — tranexamic acid, NSAIDs, a hormonal IUD, and other options. See heavy periods in perimenopause and irregular periods in perimenopause.

Iron deficiency without an obvious cause needs investigating, particularly after menopause when periods are no longer an explanation. Gastrointestinal blood loss is the concern, and bowel screening commonly begins at 45 — see health screening in your 50s.

Food

Useful alongside supplements, not a substitute when you are genuinely deficient.

  • Haem iron — red meat, liver, oily fish. Absorbed far more efficiently
  • Non-haem iron — lentils, beans, tofu, dark leafy greens, fortified cereal. Less well absorbed, and vitamin C alongside it makes a real difference
  • Cook in cast iron, which adds a small amount
  • If you eat no meat, this matters more — see vegetarian and vegan in menopause

What deficiency actually feels like

Worth listing, because every item gets attributed to menopause:

  • Exhaustion that sleep does not fix
  • Breathlessness on stairs
  • Brain fog and poor concentration
  • Hair shedding
  • Restless legs — a classic and frequently missed association; see restless legs in menopause
  • Feeling cold — see cold flashes and chills
  • Headaches, brittle nails, mouth ulcers
  • Cravings for ice or non-food substances, which is specific and worth mentioning

What to say

"I'd like ferritin checked, not just a full blood count — I have heavy periods and I'm exhausted. If I'm deficient, could we discuss alternate-day dosing, since I've read absorption is better and side effects are fewer? And what ferritin level are we aiming for before stopping?"

That covers the test, the dosing, and the endpoint — the three things that usually go unstated.

Our free printable visit prep sheet gives you a page for it, and the free 30-day symptom tracker records the bleeding that explains the deficiency.

The free 2-minute Menova self-check organizes your wider symptom picture — no account, not a diagnosis, and your answers never leave your device.

This article is general education, not medical advice or a dose recommendation. Do not take iron supplements without a confirmed deficiency — iron overload is harmful. Keep iron out of reach of children. Discuss dosing and duration with a licensed clinician or pharmacist.

Sources: NIH Office of Dietary Supplements — Iron, NHLBI — Iron-Deficiency Anemia, NHS — Iron Deficiency Anaemia, and The Menopause Society.