warum bin ich immer müde — what are common causes?

Common causes of fatigue include poor sleep, stress, nutritional deficiencies (iron, B12, vitamin D), thyroid issues, and infections. MyBody-X DNA tests may offer indirect clues: e.g., FUT2 variants affect B12 absorption; COMT/BDNF relate to stress resilience. However, effect sizes are small and evidence is mixed. Consumer DNA tests cannot diagnose fatigue. A clinical workup (blood panel, sleep assessment) is essential. Use DNA insights cautiously as one piece of a larger puzzle.