Ferritin

NutrientsMeasured in ng/mL

What it measures

The body's primary iron storage protein, used as a proxy for total iron stores.

Why it matters

It is the best single test for iron deficiency, which is common, frequently missed, and easily corrected.

Where the claimed ranges actually sit

Measured in ng/mL. Each row is one claim about where your result should fall.

What a laboratory reportsWhat a seller markets as “optimal”

Laboratory reference range24–336 ng/mL

Laboratory reference intervals; sex-specific

50–150 ng/mLC50–150 ng/mL

Longevity platforms, endurance sports programs, and iron supplement marketing

›View as table

Claim	Range	Source
Laboratory reference range	24–336 ng/mL	Laboratory reference intervals; sex-specific
50–150 ng/mL	50–150 ng/mL	Longevity platforms, endurance sports programs, and iron supplement marketing

Where the sources disagree

Both directions of error are common here. Conventional lower bounds are probably too low, particularly for menstruating women, and symptomatic deficiency is genuinely under-recognized. But the commercial fix, a tight 50–150 target, ignores that ferritin doubles as an inflammation marker. The right move is to read ferritin alongside hs-CRP and transferrin saturation, which most consumer panels report but few dashboards actually integrate.

The marketed ranges, examined

Each claim gets its strongest possible case before it gets its criticism. Several of these are substantially correct.

50–150 ng/mL

Promoted by longevity platforms, endurance sports programs, and iron supplement marketing

CConfounded

The strongest case for it

The bottom of the conventional female range is low enough that people with genuine symptomatic iron deficiency are routinely told their result is normal, which is a real clinical failure.

What it leaves out

Ferritin is an acute-phase reactant that rises with inflammation, infection, liver disease, and alcohol. A 'normal' ferritin in an inflamed person can conceal true iron deficiency, and a high result is often inflammation rather than iron excess. Interpreting it without a concurrent inflammatory marker is unreliable in both directions.

Before you act on your result

Rises with inflammation, infection, liver disease, and alcohol use, independent of iron stores.
Interpret alongside hs-CRP and transferrin saturation.
Persistently high ferritin warrants evaluation for hemochromatosis or liver disease rather than reassurance.

Last reviewed July 28, 2026How we grade evidence and attribute claims →

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