Ferritin: Meaning, Low Ferritin Causes, Symptoms, and Test Results

Ferritin

Ferritin is a protein that stores iron inside your cells and releases it when your body needs it. A ferritin blood test is one of the fastest ways to estimate your iron stores and investigate symptoms like fatigue, dizziness, hair shedding, or restless legs. Low ferritin often reflects iron deficiency, while high ferritin can rise with inflammation or liver conditions.

What Is Ferritin?

Ferritin is the body’s main iron-storage protein. It binds to iron and keeps it available for key tasks such as making healthy red blood cells, supporting muscle function, and helping organs work normally.

Because ferritin reflects stored iron, it can drop before haemoglobin becomes low. That is why people can feel unwell with “normal” haemoglobin but depleted iron stores, especially if there has been ongoing blood loss or poor absorption.

Why Ferritin Levels Matter

Iron is essential, but the body also needs tight control because excess iron can damage tissues. Ferritin helps keep iron in a safer, usable form and acts like a reserve supply.

Clinicians often interpret ferritin alongside other tests, such as serum iron, transferrin saturation, and total iron-binding capacity, to understand whether low energy or anaemia symptoms are linked to iron status.

What Causes Low Ferritin?

Low ferritin usually means your body’s iron stores are running low. Common causes include:

• Blood loss, especially heavy or prolonged menstrual bleeding.
• Pregnancy and the period after childbirth, when iron needs increase and blood loss may occur.
• Low dietary iron intake (for example, restrictive diets without enough iron-rich foods).
• Reduced absorption due to stomach or intestinal problems (such as coeliac disease, inflammatory bowel disease, or gastritis).
• Regular blood donation or recent surgery/trauma with blood loss.
• High intake of tea or coffee with meals, which can reduce iron absorption when eaten at the same time as iron-rich foods.

If ferritin is low, the priority is to find the reason. Treating the number without identifying ongoing blood loss or malabsorption can delay proper care.

Symptoms Linked With Low Ferritin

Symptoms vary by person and by how quickly iron stores have fallen. Low ferritin may be associated with:

• Tiredness, reduced stamina, or shortness of breath on exertion.
• Headaches, dizziness, or impaired concentration (“brain fog”).
• Hair shedding or brittle nails.
• Restless legs, especially at night.
• Pale skin or feeling cold more easily.

These symptoms are not specific to ferritin. A clinician may check for other causes such as thyroid disease, vitamin B12/folate deficiency, infection, inflammation, or sleep problems.

How Is Ferritin Measured?

Ferritin is measured with a simple blood test. Results are reported in nanograms per millilitre (ng/mL) or micrograms per litre (µg/L), depending on the laboratory.

Reference ranges differ between labs and by age and sex. Many laboratories use adult ranges similar to:

• Men: about 30–400 ng/mL
• Women: about 13–150 ng/mL

Your report will show the range used by your testing laboratory. Interpretation should consider symptoms, pregnancy status, inflammation markers, and other iron studies.

What Can High Ferritin Mean?

Ferritin can rise for reasons that have nothing to do with having too much iron. It is an “acute-phase reactant,” meaning it can increase with inflammation or illness.

Common causes of high ferritin include inflammation or infection, liver disease (including fatty liver), alcohol excess, metabolic syndrome, kidney disease, and some cancers. Iron overload conditions such as hereditary haemochromatosis are another possibility, especially when transferrin saturation is also high.

How To Improve Ferritin Safely

Improving ferritin usually means restoring iron stores and addressing the underlying cause. Typical approaches include dietary changes, treating sources of blood loss, and iron supplementation when appropriate.

Do not start iron supplements without medical advice. Too much iron can be harmful, and the right dose and duration depend on your test results and your health history.

Food choices that support iron intake include red meat, liver, poultry, fish, legumes, tofu, dark leafy greens, nuts, seeds, and fortified cereals. Vitamin C-rich foods (such as citrus fruit, peppers, and tomatoes) can improve iron absorption when eaten with iron-rich meals.

If tea or coffee is a daily habit, having it between meals rather than with meals can help. Your clinician may also advise further tests or, in certain cases, intravenous iron.

FAQ (Frequently Asked Questions)