Myths vs facts: CYP2D6 and Müdigkeit

A common myth is that CYP2D6 variants directly cause fatigue. In reality, CYP2D6 metabolizes many drugs (e.g., antidepressants, beta-blockers, opioids). A 'poor metabolizer' status can lead to higher drug levels, potentially causing fatigue as a side effect – but this is indirect and not guaranteed. Genetics alone rarely explains fatigue; lifestyle, sleep quality, stress, and other genes (e.g., COMT, PER3) are more influential. Direct-to-consumer tests often overstate clinical relevance. Evidence for a direct CYP2D6–fatigue link is weak (human-moderate for drug metabolism, unclear for fatigue as a standalone symptom). Caution: Never adjust medication without medical supervision.