What you carry at this position in your DNA and what research says about it.
Caffeine Metabolism: 6/10 evidence, 66 publications.
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Sample genotype (not yours): C/C
Slow Caffeine Metabolism and Higher Heart Risk
Caffeine is cleared slowly from the body, meaning its effects linger much longer. Consuming multiple cups of coffee daily is linked to an increased risk of high blood pressure and heart attacks.
What this genotype means: Slower clearance of caffeine from the body; Higher risk of high blood pressure with heavy coffee consumption; Increased risk of heart attack with heavy coffee consumption.
Sample genotype (not yours): A/A
Fast Caffeine Metabolism and Typical Heart Risk
Caffeine is cleared rapidly from the body, preventing it from lingering in the system. Consuming coffee does not increase the risk of high blood pressure or heart attacks.
What this genotype means: Rapid clearance of caffeine from the body; No increased risk of heart attack from coffee consumption; No increased risk of high blood pressure from coffee consumption.
Sample genotype (not yours): C/A
Gene function and biological role
Gene Function: The CYP1A2 gene encodes a major enzyme within the cytochrome P450 family [1]. This enzyme is primarily responsible for clearing about 95% of the caffeine in the human body [2]. It also plays a critical role in metabolizing various clinical drugs, including antipsychotics and antidepressants [3]. Enzyme activity can be highly induced by lifestyle factors such as smoking or heavy coffee consumption [4]. Understanding this gene helps clarify why individuals respond so differently to caffeinated beverages and medications.
Variant Impact: The rs762551 variant is a regulatory change located in the first intron of the CYP1A2 gene [1]. This specific genetic change determines whether an individual is a fast or slow caffeine metabolizer [4]. The A allele represents the highly inducible form of the enzyme, allowing for rapid clearance of caffeine [5]. Conversely, the C allele reduces enzyme inducibility, causing caffeine to linger in the body far longer [6]. This difference in clearance speed directly influences how caffeine affects blood pressure and cardiovascular strain [6].
Read on the Caffeine Clearance page
Key Insight: About half of the population carries at least one slow-metabolizing copy of this gene without knowing it. For these individuals, drinking multiple cups of coffee daily can significantly raise cardiovascular strain, whereas fast metabolizers may actually experience a protective effect.
Location: CYP1A2. Chromosome 15 · 15q24.1 · 74.7 Mb
Estimated prevalence by population
Global 11.0%; European 8.3%; African 15.6%; East Asian 12.2%; South Asian 18.7%; Americas 8.6%; Ashkenazi 9.9%; Finnish 9.7%; Middle Eastern 10.0%; Amish 12.3%.
Estimated CC genotype frequency.
Global 43.6%; European 41.0%; African 47.8%; East Asian 45.4%; South Asian 49.1%; Americas 41.5%; Ashkenazi 43.1%; Finnish 42.8%; Middle Eastern 43.3%; Amish 45.5%.
Estimated CA genotype frequency.
Global 45.5%; European 50.7%; African 36.6%; East Asian 42.4%; South Asian 32.2%; Americas 49.9%; Ashkenazi 47.0%; Finnish 47.5%; Middle Eastern 46.7%; Amish 42.2%.
Estimated AA genotype frequency.
Showing effects for C/C genotype
Nutrition & Metabolism
Caffeine & Stimulant Metabolism
Caffeine Metabolism. Evidence: 6/10. Source: PMID 10233211. Slow.
Cardiovascular & Metabolic
Heart Disease
Heart Attack. Evidence: 3/10. Source: PMID 16522833. Increased Risk.
Hypertension
Hypertension. Evidence: 6/10. Source: PMID 20390257. Increased Risk.
Cancer & Oncology
Breast Cancer
Breast Cancer. Evidence: 6/10. Source: PMID 17507615. Decreased Risk.
Showing effects for A/A genotype
Caffeine Metabolism. Evidence: 6/10. Source: PMID 10233211. Fast.
Heart Attack. Evidence: 3/10. Source: PMID 16522833. Typical.
Hypertension. Evidence: 6/10. Source: PMID 20390257. Typical.
Breast Cancer. Evidence: 6/10. Source: PMID 17507615. Typical.
Showing effects for C/A genotype
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Possessing the C/C genotype results in the slow-metabolizing form of the CYP1A2 enzyme [1]. Because caffeine remains in the bloodstream for an extended period, it exerts prolonged vasoconstrictive effects on the cardiovascular system [2]. Studies show that slow metabolizers who drink four or more cups of coffee per day have a significantly higher risk of nonfatal heart attacks [3]. Additionally, heavy coffee consumption in this group is associated with an increased likelihood of developing high blood pressure [4]. Interestingly, some research suggests that moderate coffee intake may offer a protective effect against breast cancer specifically for carriers of the C allele [5]. To minimize cardiovascular strain, limiting daily caffeine intake and avoiding heavy consumption is often recommended [6]. This slower clearance rate can also affect how the body processes certain prescription medications [1]. Monitoring personal sensitivity to caffeinated beverages can help guide daily habits.
Slower clearance of caffeine from the body; Higher risk of high blood pressure with heavy coffee consumption; Increased risk of heart attack with heavy coffee consumption.
Sample genotype: AA (Homozygous)
Possession of the A/A genotype encodes the highly inducible form of the CYP1A2 enzyme [1]. This allows for rapid clearance of caffeine, particularly in individuals who are regular coffee drinkers or smokers [2]. Because caffeine is processed quickly, it does not remain in the bloodstream long enough to cause prolonged cardiovascular strain [3]. Consequently, heavy coffee consumption does not elevate the risk of heart attacks or high blood pressure in this group [4]. In fact, moderate coffee intake may even provide mild cardiovascular benefits for fast metabolizers [5]. However, because caffeine is cleared so rapidly, these individuals may feel its stimulating effects less strongly [6]. This rapid metabolism also means that certain medications are processed and cleared from the body much faster [1]. Understanding this metabolic profile helps explain why coffee has such a minimal impact on sleep and heart rate for some.
Rapid clearance of caffeine from the body; No increased risk of heart attack from coffee consumption; No increased risk of high blood pressure from coffee consumption.
Sample genotype: CA (Heterozygous)
Inheriting the C/A genotype leads to a reduced rate of caffeine clearance compared to fast metabolizers [1]. The presence of a single C allele is sufficient to lower the overall inducibility of the CYP1A2 enzyme [2]. Because caffeine clears from the system slowly, its active duration in the body is significantly prolonged [3]. Research indicates that drinking several cups of coffee daily elevates the risk of myocardial infarction in these intermediate metabolizers [4]. This prolonged exposure also increases the likelihood of experiencing caffeine-induced high blood pressure [5]. However, coffee consumption has been linked to a reduced risk of breast cancer in women carrying at least one C allele [6]. Managing caffeine intake, especially later in the day, can help mitigate these cardiovascular risks [5]. Paying attention to hidden sources of caffeine like energy drinks or tea is also beneficial.
Variants with shared genetic architecture
rs2069514 · CYP1A2 Gene · Chr 15 · Caffeine and Drug Metabolism
rs2470890 · CYP1A2 Gene · Chr 15 · Caffeine and Drug Response
rs2472304 · CYP1A2 Gene · Chr 15 · Caffeine and Parkinson's
Coffee, ADORA2A, and CYP1A2: the caffeine connection in Parkinson's disease.
Coffee, CYP1A2 genotype, and risk of myocardial infarction.
CYP1A2 Genetic Variation, Coffee Intake, and Kidney Dysfunction.
The CYP1A2 -163C>A polymorphism does not alter the effects of caffeine on basketball performance.
Content updated August 2026.
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