Overview
CYP1A2 encodes an enzyme of the cytochrome P450 family responsible for breaking down caffeine, medications, and various toxins. The activity of this enzyme varies greatly between individuals and determines how quickly you metabolize caffeine.
15q24.1 (Chromosome 15)
Detoxification
Complex
~50% fast metabolizers
Function & Significance
CYP1A2 is responsible for about 95% of caffeine breakdown in the liver. The enzyme converts caffeine into paraxanthine, theobromine, and theophylline, which are then further degraded and excreted.
☕ Caffeine and Health
CYP1A2 activity influences:
- Caffeine Half-life: 2-8 hours depending on genotype
- Sleep Quality: Slow metabolizers are more sensitive
- Heart Attack Risk: Increased with high coffee consumption (>4 cups/day) in slow metabolizers
- Blood Pressure: Stronger reaction in slow metabolizers
🧬 Relevant SNPs
The C/A-163 variant (rs762551):
15:74749576
/
Significance: C/A-163 Caffeine Metabolism Variant
• AA: Fast metabolizer, rapid caffeine breakdown
• CC: Slow metabolizer, slow caffeine breakdown
• AC: Intermediate metabolizer
⚠️ Health Risks for Slow Metabolism
Slow metabolizers (CC) should note:
- Heart Attack Risk: Increased with >4 cups of coffee per day
- Hypertension: Greater blood pressure increase from caffeine
- Sleep Disorders: Caffeine should not be consumed after 2 PM
- Pregnancy: Increased risk for low birth weight
Fast metabolizers (AA): Can enjoy coffee in moderation without increased risk. Some studies even show cardioprotective effects!
📚 Data Sources
The information on this page is based on the following scientific sources:
- OMIM: #124060 – Online Mendelian Inheritance in Man
- dbSNP: rs762551 – SNP Database (NCBI)
- ClinVar: Clinical Variant Database (NCBI)
- PubMed: Caffeine Metabolism Research
- PharmGKB: Pharmacogenomics Knowledge Base
Last Update: February 2026
Biological Function
Associated Conditions
Analyzed Markers
C/A-163 - AA: fast caffeine metabolism, CC: slow metabolism, increased risk with heavy coffee intake