What is the difference between iron deficiency and anaemia?

Iron deficiency anaemia occurs when iron stores are so depleted that haemoglobin production is impaired, causing low red blood cell count. Iron deficiency without anaemia is far more common — iron stores (measured by ferritin) are low, causing debilitating symptoms, but haemoglobin remains within the normal range. Standard blood panels often miss this because they only check haemoglobin, not ferritin.

What ferritin level is considered optimal for women?

The conventional 'normal' range for ferritin is 12–150 ng/mL, but functional medicine practitioners generally consider optimal ferritin to be above 70–100 ng/mL for symptom resolution. Many women feel profoundly fatigued with ferritin levels of 15–30 ng/mL that are technically 'normal' by lab standards. If your ferritin is below 50 and you have symptoms, iron deficiency is almost certainly a contributing factor.

How long does it take to raise ferritin levels?

With consistent supplementation and dietary changes, ferritin levels typically rise by 10–20 ng/mL per month. Most women with significantly low ferritin need 3–6 months of supplementation to reach optimal levels. Retest ferritin after 3 months to confirm your levels are rising and adjust the dose if needed.

What foods are highest in iron for women?

Haem iron (from animal sources, most bioavailable): red meat, organ meats (liver is the richest source), oysters, sardines, and dark poultry meat. Non-haem iron (from plant sources, less bioavailable): lentils, chickpeas, tofu, pumpkin seeds, quinoa, and dark leafy greens. Always pair plant-based iron sources with vitamin C to enhance absorption.

Nutrition5 min readApril 6, 2026

Iron Deficiency: The Most Missed Reason Women Are Exhausted

Q: What is the best iron supplement for women?

Iron bisglycinate is the best form for most women — it is significantly better absorbed than ferrous sulfate (the most commonly prescribed form) and is far gentler on the digestive system. Always take iron with vitamin C to enhance absorption, and avoid taking it with calcium, coffee, or tea, which all inhibit absorption.

You can have iron deficiency without being anaemic. Millions of women are walking around depleted and told their blood work is 'normal.' Here's what to look for.

I spent three years being told my iron was 'fine.' My haemoglobin was within range, my doctor wasn't concerned, and yet I was so tired I could barely function. I was cold all the time, my hair was coming out in handfuls, and I had this strange restless feeling in my legs at night that made sleep impossible. It wasn't until I found a practitioner who tested my ferritin — the storage form of iron — that I discovered it was critically low.

This is the iron deficiency story I hear from women constantly. The standard iron panel checks haemoglobin and haematocrit — markers that only drop when you're clinically anaemic. But iron deficiency without anaemia is far more common, and it causes debilitating symptoms long before your haemoglobin falls. The key marker to ask for is ferritin.

What ferritin actually tells you:

Ferritin is your iron storage protein. The conventional 'normal' range for ferritin is typically 12–150 ng/mL for women — but functional medicine practitioners generally consider optimal ferritin to be above 70–100 ng/mL for symptom resolution. A ferritin of 15 ng/mL is technically 'normal' by lab standards, but many women feel profoundly fatigued at this level. If your ferritin is below 50 and you have symptoms, iron deficiency is almost certainly a contributing factor.

Symptoms of iron deficiency (even without anaemia):

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Persistent fatigue that sleep doesn't fix, cold hands and feet, hair shedding (especially diffuse thinning across the scalp), brain fog and difficulty concentrating, restless legs syndrome, shortness of breath with mild exertion, pale inner eyelids, brittle nails, and frequent headaches.

Why women are so vulnerable:

Monthly blood loss through menstruation is the primary driver — heavy periods are particularly depleting. Pregnancy and breastfeeding dramatically increase iron requirements. Plant-based diets provide non-haem iron, which is significantly less bioavailable than haem iron from animal sources. And many women are chronically under-eating protein and calories, which impairs iron absorption and transport.

On supplementation: Iron bisglycinate is the form I recommend — it's significantly better absorbed than ferrous sulfate (the most commonly prescribed form) and is far gentler on the digestive system. Always take iron with vitamin C to enhance absorption, and avoid taking it with calcium, coffee, or tea, which all inhibit absorption. Retest ferritin after 3 months to confirm your levels are rising.

This post contains affiliate links. I only recommend products I personally use and trust. Always consult your healthcare provider before starting any new supplement.

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