Ferritin

Ferritin reflects body iron stores and acute-phase inflammation simultaneously. A high ferritin with a normal hsCRP usually means true iron overload; a high ferritin with elevated hsCRP usually means inflammation. Low ferritin (under 30 ng/mL) with normal hemoglobin causes fatigue, lower testosterone, restless legs, and impaired training response long before frank anemia develops.

Optimal range

100–200ng/mL

Clinical "normal"

30–400 ng/mL

Avg. cost (US)

$35

Test frequency

Annually

When to measure

Any time of day, fasting not required.

How to measure

Standard immunoassay.

Average cost

≈ $35 cash price. Often covered by insurance with relevant ICD-10.

Why this biomarker matters

Iron is the rate-limiting cofactor for oxygen delivery, mitochondrial respiration, dopamine synthesis, and thyroid hormone conversion. Subclinical iron depletion, ferritin under 30 to 50 ng/mL with normal hemoglobin, is one of the most underdiagnosed causes of fatigue and poor exercise tolerance in men and especially in menstruating women. Endurance athletes, plant-based eaters, and frequent blood donors are at highest risk. At the other end, men carry an iron-overload risk that women generally do not until menopause, since menstruation provides a continuous iron-loss pathway. Hereditary hemochromatosis (HFE C282Y homozygosity) affects roughly 1 in 250 people of Northern European ancestry and can drive ferritin into the thousands over decades, causing cirrhosis, cardiomyopathy, diabetes, and arthropathy when undetected. A persistently elevated ferritin above 300 ng/mL in a man, especially with elevated transferrin saturation above 45 percent, deserves a workup for hemochromatosis even if symptoms are absent. The optimal range for most men sits between 70 and 200 ng/mL. Higher than that is rarely beneficial; lower is associated with reduced athletic performance, lower testosterone, and impaired recovery, particularly in trainees with high iron demand.