Ferritin is the protein that stores iron inside your cells. If iron in your blood is the cash in your wallet, ferritin is the money in your savings account. It is the most sensitive test for iron deficiency, because your body will deplete its savings (ferritin) long before it runs out of daily cash (serum iron) and develops anemia.
However, ferritin is also an 'acute phase reactant.' This means it can rise sharply in response to inflammation, infection, or liver damage, even if your actual iron stores are normal or low. This dual role makes interpreting a high ferritin result slightly more complex than interpreting a low one.
Typical Ferritin reference ranges (ng/mL or µg/L)
| Adult Men | 24 – 336 | Ranges vary significantly by laboratory |
|---|---|---|
| Adult Women | 11 – 307 | Often lower due to menstruation |
| Absolute deficiency | < 15 | Diagnostic for iron deficiency |
| Optimal target | 50 – 100 | Many doctors aim higher than the bare minimum for symptoms like fatigue |
Always compare your result to the reference range printed on YOUR report — ranges differ between laboratories and methods.
What a low ferritin means
A low ferritin is straightforward: it means your iron stores are depleted. There is virtually no other cause for a low ferritin. Even if your hemoglobin (red blood cell count) is normal, a low ferritin means you are running on empty and are at risk of developing iron deficiency anemia.
Symptoms of low iron stores include profound fatigue, weakness, brain fog, hair loss, brittle nails, restless legs syndrome, and craving non-food items like ice (pica).
The cause of low ferritin must always be investigated. In premenopausal women, heavy periods are the most common culprit. In men and postmenopausal women, gastrointestinal blood loss (such as from an ulcer or colon polyp) or poor absorption (like celiac disease) must be ruled out.
What a high ferritin means
A high ferritin is more complicated. It can mean you have too much iron (iron overload), but more often it means you have inflammation. Because ferritin is an acute phase reactant, conditions like infections, autoimmune diseases, obesity, fatty liver disease, and even daily alcohol use can push ferritin levels high.
To tell the difference, doctors usually look at a full iron panel, particularly 'transferrin saturation.' If your ferritin is high but your saturation is normal or low, the cause is likely inflammation. If both are high, true iron overload is more likely.
True iron overload can be caused by multiple blood transfusions, excessive iron supplementation, or a genetic condition called hemochromatosis, which causes the body to absorb too much iron from food.
When to actually worry — and when not to
- Ferritin below 15 ng/mL — your iron stores are empty. You need to find the cause and likely start supplementation under medical guidance.
- Ferritin above 1000 ng/mL — requires medical investigation to rule out significant inflammation, liver disease, or iron overload.
- Low ferritin in men or postmenopausal women — gastrointestinal bleeding must be ruled out, often requiring a colonoscopy.
- High ferritin with a family history of hemochromatosis — genetic testing and a full iron panel are usually the next steps.
Common questions
Should I take iron supplements if my ferritin is low?
Usually yes, but always consult your doctor first. Iron supplements can cause gastrointestinal side effects and interact with other medications. Your doctor can recommend the right dose and formulation, and investigate why your iron is low in the first place.
Can I raise my ferritin with diet alone?
If your ferritin is very low, diet alone is rarely enough to replenish stores quickly. Supplements or sometimes iron infusions are needed. However, eating iron-rich foods (like red meat, beans, and spinach) paired with vitamin C can help maintain healthy levels once restored.
Why is my ferritin high but my iron is low?
This is a classic pattern of inflammation, often called 'anemia of chronic disease.' The body hides iron away in storage (ferritin) to keep it away from potential pathogens, leaving less available in the blood (serum iron).
One value never tells the whole story.
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Upload your reportMedical disclaimer: This article is for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Reference ranges vary between laboratories — always compare your result to the range on your own report, and consult a qualified healthcare professional about your results and any symptoms.