CYP1A2 rs762551: What Your Genotype Means for Caffeine Metabolism
The rs762551 variant in the CYP1A2 gene is a well-studied genetic marker that influences the activity of the CYP1A2 enzyme. This enzyme is primarily responsible for the metabolism and clearance of caffeine from the body, leading to differences in how individuals process caffeinated beverages.
What each genotype means
Fast caffeine metabolizer
Individuals with this genotype are typically classified as fast metabolizers of caffeine due to higher CYP1A2 enzyme inducibility. Research suggests that fast metabolizers may clear caffeine more efficiently, potentially reducing the duration of caffeine-related effects. Please discuss your caffeine intake and any health concerns with your clinician or pharmacist.
Carried by approximately 43% of individuals in some studied populations.
Intermediate caffeine metabolizer
This genotype is associated with intermediate rates of caffeine metabolism compared to the AA and CC genotypes. Some studies indicate that individuals with this genotype may experience slower caffeine clearance than those with the AA genotype, which may influence sensitivity to caffeine. Please discuss your caffeine intake and any health concerns with your clinician or pharmacist.
Carried by approximately 41% of individuals in some studied populations.
Slow caffeine metabolizer
Individuals with this genotype are often classified as slow metabolizers of caffeine, which may result in a longer half-life of caffeine in the body. Research has observed that heavy coffee consumption in slow metabolizers may be associated with an increased risk of certain health markers, such as hypertension or kidney dysfunction, compared to fast metabolizers. Please discuss your caffeine intake and any health concerns with your clinician or pharmacist.
Carried by approximately 16% of individuals in some studied populations.
Understanding the rs762551 Variant
The rs762551 variant, often referred to in scientific literature as the -163C>A polymorphism, is a single-nucleotide polymorphism located within the CYP1A2 gene. This gene provides instructions for creating the cytochrome P450 1A2 enzyme, which is a critical component of the liver's detoxification system. The rs762551 variant is located in a region that influences the inducibility of this enzyme. When the enzyme is induced, it becomes more active, which can accelerate the rate at which certain substances, including caffeine, are broken down. Because this variant sits in a regulatory region, it does not change the structure of the protein itself but rather dictates how much of the enzyme is produced in response to environmental triggers, such as smoking or heavy coffee consumption.
The Role of CYP1A2 in Caffeine Metabolism
The CYP1A2 enzyme is responsible for approximately 90% to 95% of caffeine metabolism in humans. Once caffeine is ingested, it is processed by this enzyme into its primary metabolites, such as paraxanthine. Individuals with different genotypes at the rs762551 position may exhibit different rates of caffeine clearance. Those with the AA genotype are often categorized as 'rapid' metabolizers, meaning they clear caffeine from their system more efficiently. Conversely, individuals carrying the C allele (AC or CC genotypes) are often classified as 'slow' metabolizers. This difference in metabolic rate means that the same amount of caffeine can remain in the bloodstream for significantly longer periods in slow metabolizers compared to rapid metabolizers, potentially leading to prolonged effects or increased sensitivity to caffeine's physiological impacts.
Research Associations and Evidence Strength
Research has explored whether the rs762551 genotype modifies the health effects of coffee consumption, including risks related to hypertension, kidney dysfunction, and myocardial infarction. While some studies suggest that slow metabolizers (AC or CC genotypes) might experience different health outcomes when consuming high amounts of caffeine, the evidence remains limited and sometimes conflicting. Many of these associations are observed in specific populations or under specific conditions, such as heavy coffee intake or smoking status. It is important to note that while the link between this variant and caffeine metabolism rate is well-supported, the clinical significance regarding long-term health outcomes is still an area of active investigation. Current evidence does not support using this genetic information to diagnose or predict specific disease risks in a clinical setting.
Interpreting Your Genetic Information
If you have access to your genotype for rs762551, it is helpful to understand that this information describes a biological tendency rather than a medical diagnosis. Knowing whether you are a 'fast' or 'slow' metabolizer may explain why you feel the effects of caffeine for a shorter or longer duration than others. However, this information should not be used to make medical decisions or to self-prescribe changes to your diet or lifestyle based on health assumptions. If you have concerns about how caffeine affects your health, such as your blood pressure or sleep quality, the most appropriate step is to discuss these observations with your primary care physician or a registered dietitian. They can provide personalized guidance based on your overall health profile, rather than relying on a single genetic marker.
How common is this variant?
The A allele is common in European ancestry populations, with a frequency of approximately 0.65 to 0.70. Frequencies can vary significantly across different global populations.
Frequently asked questions
Does my rs762551 genotype mean I should stop drinking coffee?
No, your genotype does not dictate whether you should consume coffee. It simply provides information on how your body metabolizes caffeine, which may explain your personal sensitivity to it.
Can I use this test to predict my risk of heart disease?
Current evidence is insufficient to use this variant as a predictive tool for heart disease. While some studies have looked at associations, they do not provide a basis for clinical risk assessment.
Why do I feel jittery after one cup of coffee?
Sensitivity to caffeine is influenced by many factors, including your CYP1A2 genotype, your habitual intake, and other genetic variants like those in the ADORA2A gene. Your genotype at rs762551 may contribute to how long caffeine stays in your system.
Is the rs762551 test a medical diagnostic test?
No, this is a research-grade genetic marker. It is not used for diagnosing medical conditions or determining clinical treatment plans.
Sources & further reading
Educational information only, last refreshed 9/27/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Get my report — $29Related variants in CYP1A2
This variant in the CYP1A2 gene influences the hepatic metabolism rate of caffeine and is a key marker for individual differences in caffeine clearance.
Intronic marker associated with CYP1A2 enzyme activity and caffeine metabolism rates.
Regulatory variant associated with CYP1A2 enzyme activity, influencing the rate of caffeine metabolism and habitual coffee consumption.
A common variant in the CYP1A2 gene associated with caffeine metabolism rates.
Located in intron 1 of CYP1A2, this variant modulates inducible enzyme activity, altering systemic caffeine clearance and individual susceptibility to caffeine-related blood pressure increases.
Intronic regulatory polymorphism associated with CYP1A2 inducibility and differences in dietary caffeine metabolism rates.