What to watch with Ferritin and fatigue?

Ferritin reflects body iron stores. Low ferritin (e.g., <30 µg/L) can cause fatigue even without anemia, as iron is needed for energy metabolism and neurotransmitter function. However, ferritin is an acute-phase reactant: inflammation, infection, or liver disease can elevate it, masking a true deficiency. Therefore, interpret ferritin alongside CRP, transferrin saturation, and complete blood count. High ferritin (>200 µg/L in women, >300 µg/L in men) may indicate iron overload (hemochromatosis), metabolic syndrome, or chronic inflammation – all of which can also cause fatigue. Consumer lab tests often report ferritin without clinical context. Evidence linking ferritin alone to fatigue is moderate; a thorough workup including thyroid, vitamin D, B12, and sleep is recommended. Do not self-supplement iron without a doctor, as excess iron is toxic.