How are CYP1A2 and Sport related?

CYP1A2 encodes the enzyme responsible for metabolizing caffeine in the liver. A common variant (rs762551) classifies individuals as fast (AA) or slow (C-allele carriers) metabolizers. In sports, caffeine is a well-known ergogenic aid. Evidence suggests that fast metabolizers may experience improved endurance and reduced perceived exertion after caffeine intake, while slow metabolizers might face elevated blood pressure, jitteriness, or even impaired performance. The relationship is supported by human intervention studies, but effect sizes are moderate and vary by sport, dosage, and habituation. Direct-to-consumer DNA tests often report this variant, but their clinical utility is limited: the genotype alone does not reliably predict individual responses. A personalized caffeine strategy should consider tolerance, training status, and health conditions. Safety note: Individuals with hypertension, anxiety disorders, or pregnancy should be cautious with caffeine regardless of genotype.