Is CYP2D6 useful for Müdigkeit?

CYP2D6 is a drug-metabolizing enzyme responsible for processing many medications (e.g., antidepressants, opioids). There is no validated scientific link between CYP2D6 variants and general fatigue in healthy individuals. Claiming that a CYP2D6 genetic test can explain 'fatigue' is misleading and closer to marketing than evidence. Fatigue is multifactorial: sleep quality, stress, diet, exercise, hormones, and psychological factors play far larger roles than a single enzyme. In pharmacogenetics, CYP2D6 can be relevant if someone is taking drugs metabolized via this pathway – for example, to understand side effects like sedation. Without a medication context, the test is not useful for fatigue. The provided context contains no studies on CYP2D6 and fatigue. Evidence: unclear, leaning marketing. Caveat: No direct clinical relevance for general tiredness.