Evidence check: Ferritin in the context of Müdigkeit

Ferritin is an iron-storage protein and a key biomarker for the body's iron reserves. Low ferritin levels can indicate iron deficiency, a common cause of fatigue – especially in premenopausal women, vegetarians, or individuals with chronic blood loss. The evidence linking ferritin to fatigue is strong (human-strong) when iron deficiency anemia is present, as iron supplementation significantly improves fatigue. In non-anemic individuals with low ferritin (e.g., <30 µg/L), the evidence is mixed: some studies show fatigue improvement with iron, others do not. MyBody-X offers ferritin as a biomarker in its blood test, but note that ferritin is also an acute-phase reactant that can be elevated during inflammation, masking true iron deficiency. Therefore, concurrent measurement of CRP or other inflammatory markers is advisable. Interpretation must be clinical – an isolated low ferritin without anemia does not automatically warrant iron therapy. Caveat: Self-supplementation with iron without medical guidance can be harmful in conditions like hemochromatosis or chronic inflammation.