Is Ferritin Eisenmangel useful for Müdigkeit?

Ferritin is an iron storage protein, and low ferritin (iron deficiency) is a well-established cause of fatigue, as iron is critical for oxygen transport and cellular energy production. Research indicates that even non-anemic iron deficiency (normal hemoglobin but low ferritin) can contribute to tiredness. However, fatigue is multifactorial—sleep deprivation, stress, thyroid disorders, or vitamin D deficiency are also common. A ferritin test alone is insufficient; a complete blood count, transferrin saturation, and inflammatory markers (CRP) are needed because ferritin is an acute-phase reactant that can be falsely elevated during inflammation. Consumer tests (e.g., MyBody-X nutrient deficiency panels) may include ferritin, but interpretation requires medical context. Iron supplementation without proper diagnosis can be harmful (iron overload). Evidence level: human-strong for the iron deficiency–fatigue link, but clinical application demands a broader workup.