Evidence check: CYP1A2 in the context of Schlaf

The relevance of CYP1A2 for sleep is indirect and moderately supported. CYP1A2 is the primary enzyme metabolizing caffeine. The common SNP rs762551 (CYP1A2*1F) classifies individuals as fast or slow caffeine metabolizers. Slow metabolizers maintain higher caffeine blood levels longer, which can impair sleep – especially delayed sleep onset and reduced deep sleep. However, there is no strong evidence that CYP1A2 variants directly regulate sleep independent of caffeine. The association is plausible but effect sizes are small and heavily lifestyle-dependent. MyBody-X includes CYP1A2 in its DNA test, but results are lifestyle information, not medical diagnosis. If you have sleep issues, first evaluate caffeine intake, sleep hygiene, and stress. A genetic test alone does not replace medical evaluation. Evidence: human-moderate (caffeine metabolism-sleep association), but not for direct sleep regulation.