Evidence check: CYP1A2 in the context of Müdigkeit

CYP1A2 is a key enzyme in caffeine metabolism. Variants like rs762551 ('fast' vs. 'slow' metabolizers) influence how quickly caffeine is cleared. In the context of fatigue, caffeine is often used as a stimulant, but its effect depends on tolerance, sleep quality, and timing, not just genotype. No strong evidence directly links CYP1A2 variants to general fatigue. Some studies suggest modest differences in caffeine sensitivity, but effect sizes are small and not clinically actionable. For chronic fatigue, medical workup (iron, thyroid, sleep disorders) is far more relevant. A DNA test for CYP1A2 offers only speculative guidance. Evidence: mechanistic/unclear; no robust clinical trials confirm a fatigue link.