Understanding Ferritin: Normal vs Optimal Ranges

?What is Ferritin?

Ferritin is the body's primary iron storage protein, found mainly in the liver, spleen, and bone marrow. Serum ferritin closely reflects total body iron stores — low ferritin means iron stores are depleted, while high ferritin may indicate iron overload (haemochromatosis) or, importantly, acute-phase reaction (inflammation falsely elevates ferritin).

!Why It Matters

Ferritin is the most sensitive test for iron deficiency — it falls before haemoglobin drops, allowing early detection of iron depletion. However, ferritin is also an acute-phase reactant, meaning it rises with inflammation, infection, liver disease, and cancer — even when iron stores are normal. Interpreting ferritin always requires context. Optimal ferritin (50–150 ng/mL) is associated with best energy, cognitive function, and thyroid health.

Reference Ranges

Lab normal ranges may vary between laboratories. Optimal and longevity targets are based on research literature and should be interpreted with your physician.

Symptoms of Imbalance

• Low ferritin (<20 ng/mL): fatigue, brain fog, hair loss, restless legs syndrome, cold intolerance
• Severe iron deficiency: symptoms of anaemia (see haemoglobin)
• Very high ferritin (>1000 ng/mL): may indicate haemochromatosis, haemolysis, or serious illness

How to Improve Your Levels

• 1Iron-rich foods: red meat (heme iron, best absorbed), lentils, tofu, dark leafy greens
• 2Enhance absorption: always pair iron-rich plant foods with vitamin C
• 3Avoid tea/coffee with meals — tannins significantly inhibit iron absorption
• 4If supplementing: ferrous bisglycinate is well-tolerated and better absorbed than ferrous sulphate
• 5If ferritin is very high without inflammation: investigate for haemochromatosis

When to Test

Order alongside CBC when investigating fatigue, hair loss, or anaemia. Also check ferritin in thyroid conditions (iron deficiency impairs thyroid function). Retest every 3 months when treating iron deficiency.

Related Biomarkers