If you drink coffee every day, does it stop affecting your sleep?
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Sort of. In a 2021 trial, 20 young men who drink caffeine every day took 150 mg three times a day for 10 days, the last dose 8 hours before bed, and their sleep looked the same as on placebo. But in a 2025 trial of other daily drinkers, one big 400 mg dose still cut about 21 minutes of deep sleep when taken 12 hours before bed. A steady, moderate habit seems to cost little, and a big dose still costs deep sleep even in people who drink caffeine every day.
What we’d do
Keep the habit that held up in the trial, which was moderate cups every day, finished by mid-afternoon. Don’t count on being used to it to protect you from a big afternoon or evening dose, like a 16 oz coffee at 4pm or a pre-workout before an evening session. Then check your own nights, since nobody can feel which group they’re in.
If you remember three things
- Moderate daily cups, ending early, looked like placebo. That was 150 mg three times a day for 10 days, in 20 young men.
- A big single dose still cost deep sleep in daily drinkers. 400 mg taken 12 hours before bed cut about 21 minutes.
- Scientists still argue about tolerance. How much people build, and to which effects, isn’t settled.
Why people believe it
If you’ve had coffee every day for years and you sleep fine, it seems obvious that your body has adapted. And part of it really has. Stopping gives many daily drinkers a headache, which shows the body has adjusted to having caffeine around. In a 2004 review of withdrawal, symptoms showed up after stopping as little as 100 mg a day.
It’s like a clock ticking in the bedroom. After a while you stop hearing it. A smoke alarm going off still wakes you.
What the trials found
Ten days of steady caffeine
20 young men who drink caffeine daily. Weibel and colleagues, University of Basel, 2021
150 mg at 45 minutes, about 4 hours and about 8 hours after waking, for 10 days, then sleep measured 8 hours after the last dose. Total sleep, falling asleep, sleep stages and how well they felt they slept matched placebo. One brain wave band during sleep was lower.
Twenty healthy young men who sleep well, with no evening dose.
One big dose in daily drinkers
23 young men who drink caffeine daily, under 300 mg a day. Gardiner and colleagues, 2025
Each took their usual caffeine in the morning. On top of that, 400 mg cut about 21 minutes of deep sleep at 12 hours before bed, 15 minutes at 8 hours and 30 minutes at 4 hours. 100 mg did nothing measurable at any of the three times.
Young men measured at home with a forehead device.
What the two trials mean together
On our 5 hour math, the men in Basel went to bed with about 110 mg of caffeine in them, more than the men who took 400 mg 12 hours before bed in the 2025 trial, at about 84 mg. The Basel men slept normally, and the 2025 men lost deep sleep.
The difference is probably the pattern. The Basel men had the same three moderate doses every day for 10 days, and their bodies had settled into it. The 2025 men got one big dose, four times the size of a normal cup, on top of their usual habit. The researchers in Basel thought the one brain wave change they found might be early withdrawal during the night.
A 2022 review of caffeine and sleep by the same Basel group and others said the extent of tolerance “is still controversial and not clearly established also in humans”.
The best case for it
The Basel trial is a strong one. It was double-blind and placebo-controlled, ran for 10 days, and measured sleep in a lab. If your coffee is two or three moderate cups that end by mid-afternoon, it’s the best evidence we have, and it says your sleep is probably fine. Testing it on your own nights tells you the rest.
More detail: where the 110 mg comes from
Assume the Basel men woke at 7am. Their doses came at about 7:45am, 11:15am and 2:55pm, and they went to bed at about 10:55pm. On a 5 hour half-life, with each dose absorbed over 45 minutes, the three doses leave about 108 mg at bedtime. On a 3 hour half-life it would be about 45 mg, and on 6 hours about 136.
4 sources
- Weibel J and others, The impact of daily caffeine intake on nighttime sleep in young adult men, Scientific Reports, 2021doi.org
- Gardiner C and others, Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial, Sleep, 2025doi.org
- Reichert CF, Deboer T, Landolt HP, Adenosine, caffeine, and sleep-wake regulation: state of the science and perspectives, Journal of Sleep Research, 2022doi.org
- Juliano LM, Griffiths RR, A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features, Psychopharmacology, 2004pubmed.ncbi.nlm.nih.gov
