How long does caffeine last? The half-life of caffeine explained
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Caffeine has an average half-life of about four hours in healthy adults, with a range of two to eight hours, according to the European Food Safety Authority (EFSA). That means about half the caffeine from a drink is still in the body four hours later. How long it lasts varies with age, body weight, pregnancy, medication and liver health.
In short
• Half-life of caffeine: about 4 hours on average (2–8 hours).
• After 8 hours, roughly a quarter is still in the body (at a 4-hour half-life).
• Pregnancy, medication and liver health can make it last longer.
• EFSA: 100 mg close to bedtime may affect sleep in some adults.
Contents
- What is the half-life of caffeine?
- How much is left after a few hours?
- Why it varies
- Caffeine later in the day
- FAQ
What is the half-life of caffeine?
The half-life is the time it takes the body to remove half of the caffeine. EFSA states that in healthy adults it is about four hours on average, with a range of two to eight hours (EFSA explains caffeine).
How much is left after a few hours?
Example: a 200 ml cup of filter coffee with about 90 mg of caffeine (EUFIC), at a 4-hour half-life:
| Time | Caffeine left (approx.) |
|---|---|
| 0 hours | 90 mg |
| 4 hours | 45 mg |
| 8 hours | 23 mg |
| 12 hours | 11 mg |
Work out your own total: caffeine calculator.
Illustration only. With an 8-hour half-life, half would still be there after 8 hours.
Why it varies
According to EFSA, the half-life depends on age, body weight, pregnancy, medication and liver health. Sensitivity to caffeine also differs between people.
Caffeine later in the day
EFSA notes that a single dose of 100 mg (about 1.4 mg per kg of body weight) may affect sleep duration and patterns in some adults, especially close to bedtime. Caffeine from the afternoon can still be in the body in the evening. EFSA considers up to 400 mg a day safe for healthy adults (EFSA, 2015). More: How much caffeine a day? · How much caffeine is in coffee?
Optimal Native caffeine pouches state the caffeine per pouch: Morning Energy 200 mg, Daily Flow 75 mg, Evening Relax 0 mg. More: Caffeine pouches explained
FAQ
How long does caffeine stay in the body?
The average half-life is about four hours (2–8 hours), so it takes several half-lives for most of it to be cleared.
Why does caffeine last longer in pregnancy?
The body clears caffeine more slowly during pregnancy. More: Caffeine in pregnancy
Does caffeine affect sleep?
EFSA says 100 mg close to bedtime may affect sleep in some adults.