Ferritin — Your Body's Iron Battery
Ferritin measures the iron held in the body's stores rather than the iron circulating in the blood. Stores fall before haemoglobin does, so ferritin identifies iron deficiency at an earlier stage than a full blood count. Iron deficiency is common, particularly in women who menstruate, and can cause fatigue and reduced concentration before anaemia develops. Ferritin also rises with inflammation, so it is interpreted alongside CRP.
Why Test Ferritin?
Because 'just tired' is not a diagnosis. If you've been dragging yourself through the day, losing hair, getting headaches, or feeling weirdly breathless climbing stairs — your ferritin could be quietly tanking. It's especially worth checking if you have heavy periods, train hard, eat plant-based, or are pregnant. And if you're already supplementing iron, testing tells you whether it's actually working.
What Do High Ferritin Levels Mean?
High ferritin doesn't always mean too much iron. It can spike when your body is fighting inflammation, infection, or dealing with liver stress. That said, consistently high levels can point to haemochromatosis (iron overload) — a genetic condition that's more common than people think, especially in Scandinavia. If your levels are elevated, we'll help you figure out what's driving it.
What Do Low Ferritin Levels Mean?
Low ferritin means your iron reserves are running on empty. You might still be 'in range' on paper, but functional iron deficiency is real — and it feels like running a marathon on half a tank. Left unchecked, it progresses to full-blown anaemia. The good news? Once you know, it's very fixable.
Symptoms to Watch For
- Tiredness that sleep doesn't fix
- Dizziness or feeling lightheaded
- Pale skin or dark circles
- Brittle nails that chip easily
- Shortness of breath during normal activity
- Headaches that come and go
- Restless legs, especially at night
- Strange cravings for ice or non-food items
Who Should Get Tested?
- Women with heavy or long periods
- Anyone pregnant or planning to be
- Runners, CrossFitters, and endurance athletes
- Vegetarians and vegans
- Anyone who's been tired for longer than they can explain
- People with a family history of iron overload
- Anyone supplementing iron — to check it's actually working
How to Prepare for Your Test
Skip your iron supplements for 24 hours before the test. Try to go in the morning (before 10am) since iron levels shift throughout the day. If you're feeling unwell, wait until you've recovered — inflammation can skew the results. Don't forget your ID. Bring valid ID to your appointment. If you take a supplement containing biotin (often sold for hair and nails), pause it for two days before the test, as high doses can distort the result.
Order Your Blood Test
Test your Ferritin levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
What's a 'good' ferritin level?
My GP said my iron is fine — can I still be low?
What's the difference between ferritin and iron?
How quickly can ferritin levels improve?
Reviewed by
Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
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The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.