Metabolism Genetics: Why Some People Clear Nicotine Faster—and What It Means for Addiction
The CYP2A6 enzyme metabolizes nicotine. Genetic variation in CYP2A6 determines how fast nicotine is cleared from the body. Fast metabolizers smoke more, are more dependent, and have a harder time quitting. Metabolism genetics personalize addiction risk.
A person with high-activity CYP2A6 metabolizes nicotine rapidly—blood levels drop quickly, withdrawal hits sooner, and the urge to smoke is more frequent. A person with low-activity CYP2A6 metabolizes nicotine slowly—blood levels stay stable, withdrawal is less intense, and quitting is easier. **The same cigarette produces different addiction trajectories in different people—not because of willpower, but because of genetics. The fast metabolizer who smokes heavily is not weak. Their liver is breaking down nicotine before their brain can get enough.**
