Exhausted no matter how much you sleep. Foggy by 2pm. Hair coming out in the shower. Heart racing on the stairs.

Every one of those gets blamed on perimenopause. Every one of them can also be iron deficiency. And in your 40s, the odds that it's both are higher than at any other point in your life.

Here's why, and what to do about it.

Why is iron deficiency so common in perimenopause?

Iron deficiency is common in Australian women full stop. The Medical Journal of Australia reported in 2024 that 22.3% of Australian women have depleted iron stores (a ferritin below 30 µg/L), compared with 3.5% of men (Zhang et al., MJA, 2024). More than one in five.

Perimenopause stacks the odds further, from both ends: more iron going out, and less coming in.

More going out

• Heavier, longer, closer periods. As ovulation becomes patchy, oestrogen runs unopposed and the uterine lining builds thicker. A study of 2,329 midlife women found that up to one in three experienced heavy or prolonged bleeding during the menopause transition, and that this bleeding was strongly linked to fatigue (Harlow et al., Menopause, 2025). Shorter cycles mean more bleeding days per year. Fibroids and adenomyosis, both more common in your 40s, add to the loss.
• Pregnancies that were never fully replenished. It can take a year or more to rebuild iron stores after each baby. Plenty of women arrive in perimenopause still carrying that debt.
• Gut blood loss you may not know about, from reflux medication, anti-inflammatories, coeliac disease or gut inflammation. Always look at your poo. Black, tarry stools need a GP.

Less coming in

• Lower stomach acid and a changing gut. Iron needs acid to be absorbed. Stomach acid tends to fall in perimenopause, which is one reason so many women suddenly can't face meat, the best iron source there is. Reflux medication (PPIs) lowers acid further.
• Inflammation. Your body has a gatekeeper hormone for iron called hepcidin. When you're inflamed, hepcidin rises and shuts the gate, so less iron gets through even when you're eating plenty. Perimenopause is an inflammatory time, and inflammageing is real.
• Coffee and tea with meals. More on this below, because it's the easiest fix on the list.
• Restrictive dieting. Cutting food groups, skipping meals and low-calorie plans all cut iron intake. And they don't work in your 40s anyway; that's a whole other post.
• Vegetarian and vegan eating, which relies on non-haem iron that's absorbed far less efficiently.

Read that list again. Most women in perimenopause tick three or four of them without trying.

Is it iron, or is it perimenopause?

This is the trap. Iron deficiency and perimenopause share so many symptoms that one gets blamed for the other, and the iron never gets checked.

Usually perimenopause (hormone-driven): hot flushes and night sweats; periods closer together or skipped; new PMS or breast tenderness; vaginal dryness; weight settling around the middle; headaches around your period; dry, itchy skin.

Could be either (where women get stuck): exhausted no matter how much you sleep; brain fog; hair shedding or thinning; low mood, anxiety, short fuse; heart racing or palpitations; heavy or long periods; poor sleep and restless nights.

Points to iron (ask for iron studies): breathless on the stairs; restless legs at night; craving or chewing ice; pale inner eyelids or nail beds; sore, smooth tongue or cracked mouth corners; brittle or spoon-shaped nails; can't face meat anymore.

Ticks in the middle or right columns? Ask for iron studies including ferritin, not just a full blood count. "Normal" isn't the same as enough.

"The number of women I see who've been told their bloods are fine, and whose ferritin is sitting at 18, still surprises me. Fine for what? Not for running a household, a job and a body that's bleeding every three weeks. That's a woman being told to cope with a problem that's fixable."

Sarah McLachlan, The Perimenopause Naturopath (BHSc Naturopathy), Australia

What does iron actually do?

Iron wears a lot of hats. It carries oxygen to every cell, so low iron means low energy, breathlessness and muscle heaviness. It's needed to make neurotransmitters like dopamine and serotonin, so low iron shows up as low mood, anxiety and brain fog. It's needed for thyroid hormone production, for immune function, and for hair growth. That's why the symptom list is so long, and why iron deficiency in perimenopause can feel exactly like "perimenopause getting worse."

What is a "low" ferritin? Why normal isn't good enough

Soapbox time, and I'm not stepping off it.

Ferritin is your iron storage marker, and it's the first thing to fall. You can be iron deficient for months before your haemoglobin drops and a full blood count shows "anaemia." Iron deficiency without anaemia is still iron deficiency, and it still produces symptoms.

The problem is the reference range. Many Australian labs flag ferritin as low only below 15 or 30 µg/L. The 2024 MJA paper puts it plainly: women with a ferritin of 15 to 30 "may also have iron deficiency and will not be detected." And if you have any inflammation going on (which raises ferritin artificially), the authors suggest that a ferritin under 70 may still indicate deficiency (Zhang et al., MJA, 2024).

Ferritin alone isn't the whole story either. When I look at iron, I want to see:

• Full blood count, for haemoglobin and red cell size
• Iron studies, including ferritin and transferrin saturation
• CRP, an inflammation marker, because inflammation makes ferritin read higher than your real stores
• B12 and folate, because they travel with iron and cause overlapping symptoms

Your GP can order all of these and they're bulk-billed. If your GP isn't interested, a naturopath can order them privately. Either way, ask for the actual numbers, not "it's fine."

Can low iron cause hot flushes?

Not directly, as far as the evidence shows. Hot flushes are driven by the brain's response to falling oestrogen. But the two travel together for a reason: the same heavy, frequent bleeding that marks early perimenopause is what drains your iron. And low iron makes palpitations, anxiety, poor sleep and heat intolerance worse, which makes flushes feel bigger than they are. If you're flushing and exhausted, check both.

How to fix iron deficiency in perimenopause (properly)

Taking a supplement is the last step, not the first. If you skip the others, the supplement won't hold.

1. Fix the leak

If you're bleeding heavily, no amount of iron will keep up with the loss. Heavy bleeding in perimenopause is common, but common doesn't equal normal, and it's treatable. Start with your GP, and read why heavy bleeding happens in perimenopause so you know what to ask about.

2. Take iron every second day, not every day

This is the piece of research that changed how I dose iron. When you take an iron supplement, hepcidin (the gatekeeper) rises for about 24 hours and blocks the next dose. Swiss researchers showed that taking iron on alternate days increased absorption by 40 to 50% compared with taking it daily, and that a single dose every second day delivered about twice the iron of half that dose taken every day (Stoffel et al., Haematologica, 2019). The MJA now recommends the same (Zhang et al., 2024).

So: one dose, every second day, in the morning, with something rich in vitamin C, and away from coffee, tea and calcium.

3. Choose a form you'll actually keep taking

High-dose ferrous sulfate (Ferrograd) and iron polymaltose (Maltofer) are what most women are handed first. Both are poorly absorbed forms at a large dose, so hepcidin gets triggered, absorption drops further, and the gut gets irritated on the way through. The side effects (constipation, gut pain, nausea, black stools) often stop women taking them, and they don't move ferritin as effectively as the forms I prefer to prescribe. A supplement you've stopped taking has an absorption rate of zero.

Gentler, better-absorbed forms exist. Avoid anything with iron oxide on the label, talk to your naturopath or pharmacist about a form that suits your gut, and dose it every second day.

4. Time your coffee and tea

I'm not telling you to give up coffee. I'm telling you when to drink it. Polyphenol-rich drinks (coffee, black tea and even herbal teas like peppermint) can reduce iron absorption from a meal by 50 to 90%, depending on how strong they are. Black tea is the worst offender at 79 to 94%, and adding milk doesn't help (Hurrell et al., British Journal of Nutrition, 1999).

The fix is timing. Keep coffee and tea at least an hour away from iron-rich meals and your supplement. Coffee after breakfast, not before, is the rule that fixes most of it, and it's better for your cortisol too.

5. Eat for absorption

• Haem iron (red meat, lamb, kangaroo, sardines, mussels) is absorbed several times better than plant iron. A palm-sized serve a few times a week does more than a daily bowl of spinach.
• Pair plant iron (lentils, tofu, pumpkin seeds, dark leafy greens) with vitamin C: capsicum, citrus, tomato, kiwi.
• Keep dairy and calcium supplements away from iron-rich meals.
• If you can't face meat anymore, that's a clue in itself. Here's why it happens, and what helps.

6. Support your gut and calm the inflammation

Iron is absorbed in the upper gut, and it needs stomach acid and a healthy lining to get through. Bitter foods before meals, chewing properly, and sorting out reflux the right way (often it's low acid, not high) all help. And because hepcidin rises with inflammation, anything that lowers your inflammatory load, from sleep to blood sugar to stress, quietly raises your iron absorption too.

There's good evidence for one specific probiotic here as well. In trials in menstruating women, the strain Lactobacillus plantarum 299v increased iron absorption from a meal by roughly 20 to 30% (Hoppe et al., PLoS One, 2017). It's worth asking your naturopath about.

7. Know when to ask about an infusion

If your ferritin is very low, you're symptomatic, and oral iron isn't lifting it after three months, or you can't tolerate it at all, an iron infusion through your GP may be the right call. Sometimes it genuinely is the best option, and there's naturopathic support that can help you feel less unwell afterwards. It's a medical decision, and it's worth asking about rather than pushing on with a supplement that isn't working.

When to see your GP

If you've been told your bloods are fine and you still feel like this, you're not imagining it, and you're not being dramatic. Lab ranges are built to catch disease, not to tell you whether you have enough iron to run your life. If you'd like someone to look at your actual numbers, work out what's draining your iron, and build a plan that fits your body in this phase of life, the free Clarity Call is where we start. Not guesses. Real data.

Frequently asked questions

References

1. Zhang et al. Updating the diagnosis and management of iron deficiency in the era of routine ferritin testing of blood donors by Australian Red Cross Lifeblood. Medical Journal of Australia. 2024;221(7). mja.com.au
2. Harlow SD et al. Abnormal uterine bleeding is associated with fatigue during the menopause transition. Menopause. 2025. pubmed.ncbi.nlm.nih.gov
3. Stoffel NU et al. Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica. 2019;105(5). pmc.ncbi.nlm.nih.gov
4. Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. British Journal of Nutrition. 1999;81(4):289-295. pubmed.ncbi.nlm.nih.gov
5. Hoppe M, Önning G, Hulthén L. Freeze-dried Lactobacillus plantarum 299v increases iron absorption in young females. PLoS One. 2017;12(12):e0189141. journals.plos.org
6. Healthdirect Australia. Heavy periods (menorrhagia). healthdirect.gov.au