What to watch with CYP1A2 and Schlaf?

CYP1A2 is the primary enzyme responsible for caffeine metabolism. Genetic variants (e.g., rs762551) classify individuals as fast or slow caffeine metabolizers. Slow metabolizers have a prolonged caffeine half-life, which can impair sleep quality if caffeine is consumed later in the day. Fast metabolizers clear caffeine quickly and are less affected. However, the effect is modest: sleep is multifactorial, influenced by light exposure, stress, sleep hygiene, and other genes (e.g., CLOCK). A single gene test does not reliably predict sleep problems. Practical advice: avoid caffeine after 2 PM regardless of genotype. The evidence is based on pharmacokinetic and observational studies, not large RCTs with sleep as primary outcome. Consumer DNA tests often overstate single-SNP effects. If sleep issues persist, a comprehensive sleep assessment is recommended.