The Iron Test Women Must Know About: Ferritin Explained
Jasmine PanayiotouThe biomarkers your GP rarely checks, and how being deficient can impact the female body.
If you've been seeing the buzzword all over your social media feed and have not the slightest clue what it means, this is for you.
What is 'ferritin'?
Ferritin is the protein that stores iron in your body. While serum iron tells you how much iron is circulating right now, ferritin tells you how much you have in reserve, and for women, those reserves are always more depleted than men's due to your menstrual cycle.
If you’ve ever been told your blood results are “normal” but you’re still exhausted, losing hair, and struggling to concentrate, you may be low on ferritin.
Is ferritin the same as iron?
No, ferritin is different from iron. Iron is a mineral absorbed from your food. Ferritin is a protein that captures and stores that iron inside your red blood cells. When your body needs to make new red blood cells, it pulls iron out of ferritin and uses it to produce haemoglobin, the molecule inside cells that carries oxygen.
What happens when women don't get enough ferritin?
Low iron and low ferritin can both lead to anaemia. This is because if ferritin is depleted, haemoglobin production drops, and your red blood cells can’t carry enough oxygen, causing iron deficiency.
Iron deficiency is the most common nutritional deficiency in the world, affecting an estimated 1.2 billion people globally, with women of reproductive age being the most affected.
Around 25% of young women have iron intakes below the Lower Reference Nutrient Intake in the UK. Research published in the British Journal of Nutrition found that low ferritin, even without clinical anaemia, is significantly associated with fatigue, poor cognitive function, and hair thinning.
What are healthy ferritin levels?
The NHS defines a “normal” ferritin range as 13–150 µg/L for women. But functional medicine practitioners and emerging research suggest that symptoms of iron deficiency commonly appear below 50 µg/L, a level many women sit at without ever being flagged.
Who’s most at risk?
Women who menstruate heavily, follow plant-based diets, are pregnant or postpartum, exercise intensely, or eat a calorie-restricted diet are particularly vulnerable to low ferritin. Conditions like endometriosis, coeliac disease, and gut dysbiosis further impair iron absorption, compounding the deficit.
What to do if you're concerned about low ferritin levels:
- If you're concerned about having the symptoms associated with an iron deficiency, you can ask your GP specifically for an iron and ferritin test.
- If you’re symptomatic, try incorporating more iron-rich foods into your diet to replenish your reserves.
- If your ferritin levels are discovered to be below 50, you may require iron more quickly than what can be provided through your diet. Supplementation can be offered to get them back up.
What are the easiest ways to boost your ferritin levels?
Start with your diet
To replenish your ferritin reserves, start by incorporating more iron-rich foods into your diet. The best food sources are iron: red meat, liver, oysters, sardines, lentils, tofu, spinach, pumpkin seeds, fortified cereals, and dried apricots.
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Sources: WHO Global Anaemia Estimates 2023; NDNS UK 2022; Vaucher et al., British Journal of Nutrition 2012; NHS Ferritin Reference Ranges