Myths vs facts: Folsäure and Müdigkeit

Folic acid (vitamin B9) is crucial for cell division and red blood cell formation. Deficiency can cause megaloblastic anemia, whose hallmark symptom is fatigue. Myth: Many believe folic acid directly boosts energy or combats fatigue regardless of status. Fact: Only in confirmed deficiency does supplementation improve fatigue. In replete individuals, extra folic acid provides no energy benefit. Moreover, high folic acid intake can mask vitamin B12 deficiency, which also causes fatigue. Evidence for a general anti-fatigue effect in healthy people is weak. Direct-to-consumer tests for folate levels or MTHFR variants (e.g., rs1801133) are often misleading: even with genetic variants, benefit of supplementation without measured deficiency is unproven. Safety note: Tolerable upper intake level is 1 mg/day; higher doses only under medical supervision.