Caffeine Clearance

Your result, the DNA positions behind it, and what the research says.

7/10 confidence.

About Caffeine Clearance

CYP1A2 is the liver enzyme responsible for almost all caffeine breakdown, and CYP1A1 sits beside it sharing the same control region. Neither variant changes the enzyme itself; both sit in regulatory DNA and change how strongly the genes can be switched up when caffeine keeps arriving. The fast versions ramp up production in regular coffee drinkers; the slower ones respond less, so caffeine lingers. It explains why an afternoon coffee is harmless for some people and still noticeable at midnight for others.

Good to know: These enzymes handle about 95 percent of all caffeine breakdown. Both positions sit in control regions, changing how much enzyme is made rather than how it works. Smoking strongly induces the same enzymes, so a smoker clears caffeine faster than a non-smoker with the same result here.

Fun fact: Grapefruit juice and certain vegetables also nudge this enzyme, so the same coffee can behave differently depending on what you ate.

Discovery: The inducible version of this gene, known as CYP1A2*1F, was characterized in 1999.

The Variants

The 2 positions this trait reads

Gene: CYP1A2, CYP1A1

rs762551 CYP1A2 *1F - the inducible fast-clearing form

rs2472297 CYP1A1/1A2 shared control region - faster clearance

Location: Chr 15:74,749,576

dbSNP rs762551

The studies

Genome-wide meta-analysis identifies six novel loci associated with habitual coffee consumption (Coffee and Caffeine Genetics Consortium et al., Molecular psychiatry, 2015)

Sequence variants at CYP1A1-CYP1A2 and AHR associate with coffee consumption (Sulem P et al., Human molecular genetics, 2011)

Induction of CYP1A2 by heavy coffee consumption is associated with the CYP1A2 -163C>A polymorphism (Djordjevic N et al., European journal of clinical pharmacology, 2010)

Functional significance of a C-->A polymorphism in intron 1 of the cytochrome P450 CYP1A2 gene tested with caffeine (Sachse C et al., British journal of clinical pharmacology, 1999)

Other lifestyle traits

Caffeine Jitters: A variant in the brain receptor caffeine actually acts on, linked to how jittery or wired a moderate dose leaves you feeling.

Odor After Certain Foods: A variant in a liver enzyme that clears a fishy-smelling compound produced when gut bacteria digest choline-rich foods like eggs, fish and beans.

Lactose Tolerance: Variants near the LCT gene that set whether you keep producing lactase, the enzyme for digesting milk, into adulthood.

Back to All Traits

Content updated September 2026.

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