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ENZYMEDefinition: sourced draft

CYP1A2

A liver enzyme important in caffeine metabolism; activity varies with exposures and physiology.

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Connections & claims

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Claim · not formally assessed

Tobacco-smoke exposure induces CYP1A2 activity; stopping smoking reduced caffeine clearance in the cited study.

Heavy smokers undergoing cessation. Tobacco smoke is a metabolic exposure, not a caffeine route.

Source

Limitation Enzyme activity decline after cessation is not caffeine elimination half-life.

Caffeine · Sourced draft
metabolic pathway

Caffeine clearance

Tobacco-smoke exposure induces CYP1A2. The study measured declining caffeine clearance after cessation; enzyme activity decline is not caffeine elimination half-life.

Relationship source 1

Linked substances

1 entries

Tagged articles and participants in the relationships above. A shared tag alone does not establish a causal effect.

Stimulant

Caffeine

A familiar stimulant with an unusually rich evidence base. Its effects depend on timing, tolerance and how quickly your body clears it.

Sourced draft

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Definition sources

Supporting reading for this original editorial definition. Independent editorial review has not been recorded.

Observation & claim sources

  1. Human pharmacokinetic study · 2004

    Time response of cytochrome P450 1A2 activity on cessation of heavy smoking

    Faber & Fuhr

    Caffeine clearance decreased after cessation in 12 heavy smokers.

    Limitation Small selected sample. The reported half-life of enzyme activity change must not be confused with caffeine elimination half-life.

    Funding / disclosures Not assessed; consult the original disclosure.

    Source in Caffeine