The 90-minute coffee rule says that instead of drinking coffee the moment you wake, you wait roughly 90 minutes. The two mechanisms it rests on are established, but the specific delay is a practical suggestion rather than a finding from a controlled trial.
Josie Winfield
Head of Training · 1 June 2023 · 4 min read
Reviewed by
Faizana Karim
Eleven years in practice, specialising in women's hormone health
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The idea is simple. Instead of drinking coffee the moment you wake, you wait roughly 90 minutes. It was popularised by the neuroscientist Andrew Huberman on the Huberman Lab podcast, and the reasoning rests on two mechanisms that are well described in the research: the cortisol awakening response, and the way caffeine blocks adenosine.
Worth being clear at the outset. The two mechanisms are established. The specific 90-minute delay is a practical suggestion built on top of them, not a finding from a controlled trial. Treat it as something to test on yourself, not a rule.
Cortisol rises sharply in the 30 to 45 minutes after waking. This is the cortisol awakening response, and it is part of how the body shifts from sleep to alertness. Because cortisol is already doing that job, the argument goes, caffeine taken in the same window adds less than it would an hour or two later.
Note carefully what is and is not established here. The cortisol awakening response itself is well documented. Whether caffeine taken during it blunts the cortisol rise, or blunts the effect of the caffeine, has not been demonstrated in controlled research. That part is unverified.
Caffeine works mainly by binding to adenosine receptors without activating them. Adenosine accumulates across the day and promotes sleepiness, so occupying its receptors reduces the feeling of tiredness. Immediately after a full night’s sleep, adenosine levels are low, and they build as the morning goes on.
The proposed benefit of waiting is that caffeine has more adenosine to compete with by the time you drink it. This is a reasonable inference from the pharmacology. It has not been tested as a timing intervention, so we are not going to state it as fact.
Two things sit on firm ground. Caffeine’s action as an adenosine receptor antagonist is well established. So is its effect on sleep: caffeine taken even six hours before bed measurably reduces total sleep time. For most people, how much caffeine they have and how late in the day they have it matter considerably more than whether the first cup lands at 7am or 8.30am.
If you want to try delaying your first coffee, the honest framing is that it is a low risk experiment with a plausible mechanism and no trial data behind the specific timing. Judge it on how you feel rather than on the theory.
Rather than jumping straight to 90 minutes, delay your first coffee by 15 minutes, then 30, and build from there. It is easier to keep.
You wake mildly dehydrated after a night's sleep. A glass of water gives the morning routine something to do while you wait.
Protein and complex carbohydrates at breakfast give you energy that is not caffeine dependent.
This is the part with real evidence behind it. Late caffeine costs you sleep, and lost sleep costs you more than badly timed coffee ever will.
Reviewed August 2026. The original version presented the 90-minute rule as established physiology. It has been rewritten to separate what the research supports from what is inference, and citations have been added.
Josie Winfield
Head of Training
Josie has worked in fitness for eight years, first as a personal trainer and now as a tutor and assessor at Create. She has competed in CrossFit at elite level and specialises in nutrition.
Reviewed by Faizana Karim, Eleven years in practice, specialising in women's hormone health.
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