Metabolism Chemistry

Your liver processes caffeine and alcohol through cytochrome P450 enzymes, proteins that chemically modify foreign molecules so the body can flush them out.

Genetic differences in these enzymes create very different responses, and this is the same variation behind that population-average half-life. Fast metabolizers clear caffeine in 2-3 hours and can drink coffee at night without sleep problems. Slow metabolizers take 8+ hours, making an afternoon espresso a recipe for insomnia.

The same genetic logic shapes how we handle alcohol. The drug disulfiram deliberately blocks aldehyde dehydrogenase, the enzyme that clears toxic acetaldehyde, so even one drink triggers severe nausea — a chemical treatment used to discourage drinking.