Ferritin: what is a good level?
Reference ranges are extremely wide — commonly about 30–400 ng/mL for men and 15–200 ng/mL for women, varying by laboratory. A woman with a ferritin of 18 ng/mL and a man at 350 ng/mL are both inside the printed range and both receive no flag.
This is the range used by the inflammatory dial in the Longevity Score calculator. It is deliberately tighter than the range printed on a standard lab report — the reasoning is below.
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A result anywhere in the pale band is reported as normal and generates no comment. The brighter band is where risk is lowest. The distance between them is the part a standard report does not tell you.
What Ferritin actually measures
Ferritin is the protein that stores iron inside cells. The small amount that leaks into serum is proportional to total body iron stores, which makes it the standard first-line test of iron status.
It is also an acute-phase reactant: inflammation raises it independently of iron. Ferritin therefore reports two different things at once, and separating them is the whole difficulty of interpreting it.
Why it matters
Iron is scored on the inflammatory dial rather than a nutritional one because the risk at both ends runs through oxidative stress. Free iron catalyses the reactions that generate reactive oxygen species.
Low ferritin means depleted stores, and the consequences — fatigue, impaired aerobic capacity, poor exercise adaptation, restless legs — appear well before anaemia does. Haemoglobin is the last thing to fall, not the first.
High ferritin, in the absence of inflammation, means iron accumulation. Iron is not actively excreted, so stores tend to rise with age in men and after menopause in women, and excess is associated with insulin resistance and liver injury.
Why it's on the dashboard
Ferritin earns a U-shaped band rather than a simple floor or ceiling because the evidence runs in both directions at once. On lifespan, Kadoglou et al.'s English Longitudinal Study of Ageing (PLOS ONE, 2017), following 5,471 adults over 50 for a mean of 7.7 years, found the highest ferritin quartile in men (194–598 ng/mL) carried a 49% higher all-cause mortality risk even after excluding major chronic disease at baseline — while the lowest quartile in women carried its own excess risk, the same U-shape this dial's band is built to catch, in one dataset. On healthspan, Vaucher et al.'s randomised controlled trial (CMAJ, 2012) gave oral iron to 198 non-anaemic women with unexplained fatigue and ferritin under 50 µg/L and found fatigue scores improved significantly more than with placebo in 12 weeks — causal evidence, not just correlation, that depleted iron stores cause real functional symptoms well before haemoglobin falls. See the Inflammatory dial for the broader context.
Why this range is stricter than your lab's
The lower bound of the standard range is set at the point where iron-deficiency anaemia becomes likely, not where iron stores are adequate for normal function. Symptomatic deficiency is routine between 15 and 30 ng/mL.
The upper bound is similarly permissive, drawn from a population in which subclinical inflammation and gradual iron loading are both common. A value of 300 ng/mL is typical of the population and not a sign of health.
Because the harm is U-shaped, this is one of the few markers where the engine penalises both directions. More is not better, and the optimum is a band rather than a floor or a ceiling.
This distinction applies across the whole panel, not just this marker — see optimal versus standard lab ranges for the general case.
What moves Ferritin
Educational information, not a treatment plan. Discuss changes to medication or supplementation with a clinician who knows your history.
How fast it responds
Months. Stores change slowly in either direction — three to six months to correct a deficiency, and comparably long to reduce an elevated value. Retest no sooner than 12 weeks. See response times across all markers for how this compares.
What can distort the result
- Any infection, injury or inflammatory flare raises ferritin and can mask true iron deficiency entirely. Always interpret alongside hs-CRP.
- Where ferritin and CRP are both raised, transferrin saturation is the more informative measurement.
- Optimal ranges are sex-specific, and the engine scores them that way.
- Persistently high ferritin with high transferrin saturation can indicate haemochromatosis, which is common, genetic and treatable — worth proper investigation rather than a supplement change.
- Heavy endurance training lowers ferritin through several mechanisms at once, and athletes often need stores at the higher end of the optimal band.
Frequently asked questions
What is a good Ferritin level?
The longevity-optimised target used in this calculator is 50–100 ng/mL (men), 30–80 ng/mL (women). Reference ranges are extremely wide — commonly about 30–400 ng/mL for men and 15–200 ng/mL for women, varying by laboratory. A woman with a ferritin of 18 ng/mL and a man at 350 ng/mL are both inside the printed range and both receive no flag.
Why is this target stricter than the range on my lab report?
The lower bound of the standard range is set at the point where iron-deficiency anaemia becomes likely, not where iron stores are adequate for normal function. Symptomatic deficiency is routine between 15 and 30 ng/mL.
How fast does Ferritin respond to change?
Months. Stores change slowly in either direction — three to six months to correct a deficiency, and comparably long to reduce an elevated value. Retest no sooner than 12 weeks.
Related markers
Ferritin feeds the inflammatory dial, and read it alongside hs-CRP · ALT.