Evidence check: MTHFR in the context of Müdigkeit

The link between MTHFR variants (C677T) and fatigue is poorly supported by evidence. Available data (human-moderate) come mainly from studies on pregnancy and autism, not fatigue. MTHFR polymorphisms are common and usually benign; they only modestly reduce enzyme activity. Consumer DNA tests often overstate clinical significance. Fatigue has many causes (sleep, stress, diet, hormones, infections), so a single gene variant rarely explains it. Supplementation with methylfolate or other nutrients is not indicated without medical evaluation and may carry risks if overdosed. Evidence for benefit in fatigue is insufficient. Beware of marketing claims: most people with MTHFR variants are asymptomatic. A holistic approach with proper medical diagnostics is recommended.