What is ferritin?
Ferritin is the primary intracellular iron storage protein found in almost every tissue in the body. Circulating serum ferritin correlates with total body iron stores — it is the best single test for assessing whether you have adequate iron reserves. Each ferritin molecule can store up to 4,500 iron atoms.
Unlike haemoglobin, which measures iron in red blood cells, ferritin reflects the iron depot your body draws on when demands increase. You can have completely normal haemoglobin while ferritin is critically depleted — this is the state of iron deficiency without anaemia, and it is the most commonly missed iron-related diagnosis in India.
Why ferritin ≠ haemoglobin
The body maintains haemoglobin levels at the expense of iron stores. When dietary iron is insufficient, the body first depletes ferritin, then tissue iron, and only finally allows haemoglobin to fall. By the time haemoglobin drops, you are in frank iron-deficiency anaemia — a late-stage finding. Ferritin depletion can exist for months or years before haemoglobin shifts.
This is clinically important: a CBC with "normal" haemoglobin does not rule out iron depletion. Always request serum ferritin specifically if you are investigating fatigue, hair loss, exercise intolerance, or cognitive symptoms.
Symptoms of low ferritin
- Fatigue and reduced stamina — iron is required for mitochondrial energy production, not just oxygen transport
- Hair shedding (telogen effluvium) — the most common cause of diffuse hair loss in Indian women under 40
- Brain fog and reduced concentration — iron is critical for dopamine synthesis and myelin formation
- Cold hands and feet — impaired thermogenesis
- Restless legs syndrome — strongly associated with low ferritin
- Reduced exercise capacity — impaired VO₂ max and muscle function
- Palpitations — at very low levels, even with normal haemoglobin
Ferritin as an acute phase reactant
An important caveat: ferritin is also an acute phase protein. During inflammation, infection, or metabolic stress, the liver increases ferritin production independently of iron stores. This means a "normal" or even elevated ferritin can be misleading if inflammation is present.
Always measure hsCRP alongside ferritin. If hsCRP is elevated (>1.0 mg/L), ferritin may be artificially raised by inflammation. A ferritin of 60 ng/mL with hsCRP of 5 mg/L may reflect iron deficiency masked by inflammation — transferrin saturation and serum iron provide additional context.
Reference ranges vs optimal ranges
Standard Indian lab reference ranges flag ferritin as deficient only below 12–15 ng/mL in women and 30 ng/mL in men. These represent the threshold for frank anaemia — not functional adequacy. Most longevity and functional medicine physicians target 70–150 ng/mL for both sexes as the range associated with symptom-free iron status and optimal physiological function.
| Ferritin Level | Category | Common Symptoms | Action |
|---|---|---|---|
| <12 ng/mL (women) / <30 ng/mL (men) | Iron deficient | Fatigue, hair loss, brain fog, palpitations | Supplement aggressively; investigate cause |
| 12–50 ng/mL | Suboptimal | Mild fatigue, reduced exercise tolerance, early hair thinning | Supplement and optimise diet; retest at 3 months |
| 50–70 ng/mL | Borderline adequate | Minimal symptoms in most; still below longevity target | Supplement to optimise; monitor dietary iron |
| 70–150 ng/mL | Optimal (longevity target) | None expected | Maintain; retest annually |
| 150–300 ng/mL | High-normal | Usually asymptomatic; check hsCRP | Rule out inflammation; continue monitoring |
| >300 ng/mL | Elevated — investigate | May indicate iron overload, liver disease, or chronic inflammation | Check hsCRP, liver enzymes, transferrin saturation; consider haemochromatosis |
Causes of low ferritin in India
- Vegetarian diet — plant-based non-haem iron has 5–15% absorption vs 20–30% for haem iron from meat; phytates in grains further impair absorption
- Heavy menstruation — the most common cause in women under 45; monthly losses of 80ml+ can outpace dietary intake
- Pregnancy and lactation — dramatically increased iron demand
- Frequent blood donation — each donation removes ~250mg iron
- Malabsorption — coeliac disease (underdiagnosed in India), H. pylori infection lowering stomach acid, inflammatory bowel disease
- High tea and coffee consumption — tannins bind non-haem iron; consuming with meals reduces absorption by 50–90%
- Calcium supplementation with meals — competes directly with iron absorption
- Intense exercise — increased requirements, foot-strike haemolysis, GI losses
Supplements & interventions to raise ferritin
Iron bisglycinate is the preferred supplement form — chelated iron with significantly less GI side effects (constipation, nausea) compared to ferrous sulphate, and comparable or superior absorption. Ferrous sulphate is cheaper but causes GI issues that lead to non-compliance.
- Dose: 18–36 mg elemental iron daily or every other day (alternate-day dosing reduces hepcidin upregulation and may improve net absorption)
- With vitamin C: 100–250 mg ascorbic acid taken simultaneously significantly enhances non-haem iron absorption
- Timing: On an empty stomach or between meals for best absorption
- Avoid: Calcium, dairy, tea, coffee within 2 hours of iron supplement
- Timeline: Ferritin rises ~5–10 ng/mL per month; retest at 3 months; continue until 70–100+ ng/mL
Do not supplement iron without testing first. Iron overload (haemochromatosis or supplementation excess) is harmful and pro-oxidant. Test ferritin, then supplement only if below 70 ng/mL and you do not have signs of active inflammation driving ferritin artificially high.
When ferritin is high
Ferritin above 300 ng/mL warrants investigation. In most cases, elevated ferritin reflects acute-phase inflammation rather than true iron overload. Check hsCRP, liver enzymes (ALT, AST), and transferrin saturation.
True iron overload — hereditary haemochromatosis — is less common in Indian populations than in Northern Europeans but does occur. If transferrin saturation exceeds 45% alongside elevated ferritin, genetic testing for HFE mutations is warranted.
How often to test
If ferritin is depleted and you are supplementing: retest every 3 months until you reach target range. Once at 70–150 ng/mL: test annually as part of a standard health panel. If you are a menstruating woman, heavy exerciser, or vegetarian: include ferritin in your annual panel without exception.
Related biomarkers
Ferritin should be interpreted alongside: haemoglobin and CBC (to rule out anaemia), serum iron and transferrin saturation (for fuller iron panel), hsCRP (to rule out inflammation confounding ferritin), and methylcobalamin / B12 (B12 deficiency co-exists with iron deficiency in Indian vegetarians and shares symptoms).
Frequently asked questions
What is a good ferritin level in India?
Most labs report normal as ≥12 ng/mL. The longevity target is 70–150 ng/mL. Below 50 ng/mL is suboptimal; symptoms are common below 30 ng/mL even with normal haemoglobin.
Can ferritin be normal but I'm still iron deficient?
Yes. Ferritin rises during inflammation and can appear normal even when true iron stores are depleted. Always check hsCRP alongside ferritin. Transferrin saturation below 20% despite normal ferritin is another signal.
How long to raise ferritin with iron supplements?
Expect 5–10 ng/mL rise per month with consistent supplementation. Retest at 3 months. Full repletion from severely low levels may take 6–12 months.
Why is ferritin low even though I eat meat?
Heavy menstruation, GI malabsorption, high tea or coffee intake with meals, calcium supplements, frequent blood donation, and intense exercise can all deplete ferritin despite meat consumption.