Caffeine Half-Life & Clearance
Understand how long Caffeine stays in your bloodstream, its metabolic pathways, and how to time your doses optimally.
Standard Pharmacokinetics
Chart represents a single standard dose processed by a normal metabolizer over 24 hours.
Key Metrics
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Open Interactive CalculatorMetabolism & Excretion
Pathway
Hepatic CYP1A2 (primarily), CYP2E1, CYP3A4
Elimination
Urine (as metabolites: paraxanthine, theobromine, theophylline)
Important Nuances
Highly variable: 2–3 hrs in CYP1A2 ultrarapid metabolizers; 8–10 hrs in slow metabolizers. Oral contraceptives can double half-life.
Frequently Asked Questions
What is the half-life of caffeine?
Caffeine has an average half-life of about 5–6 hours, but this varies enormously by individual genetics (CYP1A2). Fast metabolizers may clear caffeine in 3 hours; slow metabolizers may take 9+ hours.
When should I take my last caffeine before sleep?
For most people, the last caffeine dose should be at least 6 hours before bedtime. If you are a slow caffeine metabolizer (CYP1A2 slow), 8–10 hours is safer.
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