Myths vs facts: CYP1A2 and Sport

Myth: Your CYP1A2 genotype alone determines whether caffeine is effective or dangerous for sport. Fact: The rs762551 variant (AA = fast, CC = slow metabolizer) affects caffeine clearance, but individual response depends on training, tolerance, other genes (e.g., ADORA2A), and dosage. Fast metabolizers (AA) clear caffeine faster but still risk side effects (anxiety, insomnia, elevated heart rate) at high doses (>6 mg/kg). Slow metabolizers (CC) may benefit from lower doses (2–3 mg/kg) and should avoid excessive intake. Human evidence strongly supports the metabolic difference, but sports performance outcomes are highly individual. Marketing often overstates the predictive power of single SNPs. Safety note: Caffeine can interact with magnesium; ensure adequate intake when using high doses.