About CaffIQ and who writes it

CaffIQ is an iPhone app that shows how today’s coffee, tea and energy drinks will affect tonight’s sleep — and how late you can still enjoy the next cup. It is built and written by one independent developer, Guillaume Brard. There is no team, no agency and no sponsor behind these pages.

Why an app comes with a library

The app answers one question: how much caffeine is in you right now, and when will it be low enough to sleep. Answering it well means using a pharmacokinetic model, and a model is only useful if you understand what it assumes. These articles exist so the numbers in the app are explainable rather than magic — what a half-life is, why the same cup lands differently on two people, and where the evidence stops.

How the articles are written

• Figures come with a source. Reference points are taken from food-safety authorities — EFSA in the EU, ANSES in France, the FDA in the US — and from peer-reviewed research, and they are stated in milligrams and hours rather than in cups.
• No health claims, ever. Nothing here treats, prevents or cures anything. The articles describe pharmacology; they never promise a benefit.
• Uncertainty is stated, not smoothed over. Where the research is thin or contested, the article says so instead of picking the tidier answer.
• Corrections are made in place. When something turns out to be wrong, the article is fixed and its update date moves.

What this is not

I am not a doctor, a dietitian or any kind of health professional, and neither this site nor the app is a medical device. Everything here is general information about how caffeine behaves in the body. For anything touching your own health — pregnancy, medication, a heart condition, sleep problems that worry you — talk to a qualified professional. That advice appears at the bottom of every article for the same reason it appears here.

Getting in touch

Corrections are welcome and get priority: if a figure here is wrong or a source has moved, write to contact@caffiq.app and it will be fixed. The same address handles questions about the app.