Every calculation in this tool is built on published, citable research — consistent with our GENSENSE™ standard of third-party verified, peer-reviewed backing for every claim we make.
- Caffeine's decay follows standard first-order elimination kinetics, the same pharmacokinetic model used for any substance with a defined half-life.
- CYP1A2 accounts for 95%+ of caffeine metabolism — Guest et al., 2018, cited via FitnessGenes, "What Does Your DNA Say About Caffeine? CYP1A2, ADORA2A, and Your Metabolism." Genotype half-life ranges (fast ~2.5h, slow ~9-10h) drawn from the same source.
- Pregnancy extends caffeine half-life by roughly 8-16 hours — cited via Ember Coffee, "Coffee and Sleep: How Late Is Too Late for Your Last Cup?"
- Regular coffee drinkers show measurable tolerance via adenosine receptor adaptation — a peer-reviewed cross-sectional study of the Swedish Cardiopulmonary Bioimage Study (SCAPIS) cohort, n=30,154, published on PubMed Central: "Habitual coffee consumption poorly correlates with sleep quality and daytime sleepiness."
- Bean species caffeine content (Arabica ~1.2-1.5%, Robusta ~2.2-2.7%) — Colipse Coffee, "Arabica vs Robusta Coffee Beans: Caffeine, Taste, and Key Differences."
- Roast level's effect on caffeine when measured by volume vs. weight — Dabov Specialty Coffee, "Roast Level vs. Caffeine Content: The Real Science."
- Decaf residual caffeine: Swiss Water® Process removes approximately 99.9% of caffeine (~2mg per cup); other decaffeination methods typically remove 90-95% (~10-15mg per cup) — consistent with our own Swiss Water® decaf science article, and standard beverage/medication caffeine reference values.
Where a specific peer-reviewed study is cited above, we name it directly. A few facts (species caffeine content, roast/volume effects) are well-established industry reference figures rather than a single traceable paper — we've cited the specialty-coffee source we verified them against.
Want the full research writeup, with every citation and the complete mechanism explained? Read the full article →
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