If you are tired in a way sleep does not fix, losing hair, and your periods have been heavy for a couple of years, there is one inexpensive blood test worth asking for before anything else. Iron deficiency is the most common nutritional deficiency worldwide, it is extremely common in perimenopause for an obvious mechanical reason, and it produces almost exactly the symptom list everyone attributes to hormones.

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. Do not start iron supplements without testing first — more on why below.

Why perimenopause depletes iron

Heavy periods. That is most of it.

As ovulation becomes intermittent, cycles can be heavier, longer, and closer together — the pattern described in irregular periods in perimenopause and heavy periods. Fibroids compound it further; see fibroids in perimenopause.

Blood loss month after month draws down iron stores faster than diet replaces them. The depletion is gradual, which is exactly why it is missed: there is no day when you notice it start, and each month feels only slightly worse than the last.

Deficiency comes before anemia

This is the single most useful thing to understand, and the reason so many women are told their bloods are "normal."

Iron depletion happens in stages. Stores fall first — measured by ferritin. Only later does haemoglobin drop, which is what defines anemia. Symptoms frequently begin in that first stage, while your full blood count still looks fine.

So a normal haemoglobin does not rule out iron deficiency. If ferritin was not measured, the question was not answered. Ask for it by name.

One caveat worth knowing: ferritin also rises with inflammation, infection, and liver disease, so a normal-looking result in the presence of inflammation can be misleading. If your clinician suspects that, they may add CRP or transferrin saturation to interpret it properly.

Symptoms, and why they get called menopause

  • Exhaustion that sleep does not resolve
  • Breathlessness on stairs, or a racing heart with mild exertion
  • Brain fog and poor concentration — see why brain fog happens
  • Hair shedding, particularly diffuse thinning
  • Restless legs, especially at night, wrecking sleep
  • Headaches, dizziness, feeling cold
  • Pale skin, brittle nails, cracks at the corners of the mouth
  • Low mood and irritability
  • Unusual cravings for ice or non-food substances — an odd but recognized sign

Every item on that list also appears on a menopause symptom list. That overlap is the whole problem, and it is why "it's just your age" is such an expensive answer. See when menopause might not be the answer.

The tests to ask for

Specifically:

  • Ferritin — iron stores. The key test, and the one most often skipped.
  • Full blood count — haemoglobin and mean cell volume, to see whether anemia has developed.
  • Transferrin saturation and CRP in some cases, to interpret ferritin properly.
  • Thyroid function at the same time, since it produces an overlapping picture and it is efficient to check together; see perimenopause versus thyroid.
  • B12 and vitamin D, commonly checked alongside.

Phrase it plainly: "Could we check ferritin, not just haemoglobin? My periods have been heavy and I'm exhausted."

There is genuine debate about what ferritin level counts as low, and thresholds differ between laboratories and guidelines. If your result sits at the bottom of the range and your symptoms fit, that is worth a conversation rather than an automatic dismissal — some clinicians treat symptomatic women whose ferritin is low-normal.

Finding the cause matters as much as fixing the number

Iron deficiency is a finding, not a diagnosis. In a perimenopausal woman with heavy periods the cause is usually obvious — but it should still be stated rather than assumed, and the bleeding treated in its own right.

One important safety point: iron deficiency in a postmenopausal woman, or in anyone without an obvious source of blood loss, generally warrants investigation of the gastrointestinal tract. Periods are not an available explanation once they have stopped, and this is a situation where "just take iron" without looking for a cause is not adequate care.

How to correct it properly

Oral iron is first-line. Three practical points that make a large difference:

  • Alternate-day dosing is often better absorbed than daily. Taking iron raises hepcidin, a hormone that blocks absorption for the following day or so — which is why every-other-day dosing can deliver as much or more iron with fewer side effects. Ask your clinician about it.
  • Take it with vitamin C or a glass of orange juice, and away from tea, coffee, milk, calcium supplements, and acid-reducing medication, all of which impair absorption.
  • Expect it to be slow. Haemoglobin responds in weeks; refilling stores takes about three to six months of continued treatment. Stopping as soon as you feel better is the most common reason it recurs.

Side effects — constipation, nausea, dark stools — are common and are the usual reason people quit. Alternate-day dosing, a different formulation, or a lower dose usually solves it. Do not simply stop; say it is not tolerable and ask for an alternative.

Intravenous iron is available for people who cannot absorb or tolerate oral iron, or who need correcting faster. It is a legitimate route, not an extreme measure.

Diet alone rarely corrects an established deficiency, though it supports maintenance: red meat, liver, and shellfish are the most bioavailable sources, while pulses, tofu, fortified cereals, and dark leafy greens contribute non-haem iron, absorbed better in the presence of vitamin C. Our guide to eating for menopause covers the wider picture.

Why you should not self-treat blind

Two reasons. Iron overload is a real risk for people with haemochromatosis, a genetic condition that is not rare, and taking iron without testing can cause harm. And treating without looking for the cause can delay finding something that needs attention. Test, treat, and re-test.

Treat the bleeding too

If heavy periods are the cause, iron replacement is patching the consequence. Options that reduce blood loss — a hormonal IUD, tranexamic acid, NSAIDs, or treatment for fibroids — address the source, and are covered in heavy periods in perimenopause. Doing both is usually the right answer.

What to bring to the appointment

Two or three cycles of bleeding records make this conversation much shorter: days of bleeding, how heavy each day, clots, and any bleeding between periods. Add your main symptoms and when they started.

Our free printable 30-day symptom tracker has a bleeding column for exactly this, and the free visit prep sheet condenses it to one page with space for the test requests above.

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

Related: when iron is not the answer, how to actually take iron, heavy periods in perimenopause, acid-reducing medication and absorption, coeliac disease, and giving blood in perimenopause. The full test list is in which tests to ask for.

This article is general education, not medical advice or a diagnosis. Do not start iron supplements without blood tests and clinical advice. Iron deficiency after menopause, or without an obvious cause, needs proper investigation.

Sources: NHLBI — Iron-Deficiency Anemia, ACOG — Anemia, NICE NG88 — Heavy Menstrual Bleeding, and NHS — Iron Deficiency Anaemia.