Is Ferritin useful for fatigue?

Ferritin is a key biomarker for iron stores. Low ferritin is strongly associated with fatigue, especially in iron-deficiency anemia. However, fatigue is multifactorial; low ferritin without anemia (non-anemic iron deficiency) can also cause tiredness. Evidence is human-strong: multiple studies link iron status to energy levels. Caveat: ferritin is an acute-phase reactant; it can be falsely elevated during inflammation, masking true deficiency. A single ferritin test is insufficient; a full iron panel (including transferrin saturation, TIBC, and CRP) is recommended. High ferritin may indicate hemochromatosis or chronic disease, also linked to fatigue. Do not self-supplement without testing – iron overload is harmful. For consumer labs: results should be interpreted by a clinician. Evidence grade: human-strong.