Is the 90 minute coffee rule true? Debunking the viral morning routine

Over two-thirds of Americans drink coffee daily, but a viral wellness trend suggests delaying that first cup for 90 minutes to optimize energy. But is the 90 minute coffee rule true? This article explores the science behind the claim and helps you determine if it's right for you.

Quick Summary

The popular 90-minute coffee rule, suggesting a delayed caffeine intake, has conflicting scientific evidence and is not supported by robust research on cortisol and adenosine.

Key Points

• Viral Theory: The 90-minute rule, popularized by Andrew Huberman, suggests delaying morning coffee to avoid interfering with natural cortisol and adenosine cycles.

• Scientific Flaws: The scientific claims are largely inaccurate; adenosine accumulates after waking, and regular coffee drinkers develop tolerance to cortisol effects.

• Individual Variation: The optimal timing for caffeine is highly personal, depending on individual genetics, metabolism, and lifestyle.

• No Afternoon Crash Fix: The post-lunch energy slump is more related to natural circadian rhythm and meal timing than morning coffee intake.

• Listen to Your Body: A more effective strategy is to observe your natural energy patterns and time coffee strategically for maximum benefit.

• Consistent Habits: Prioritizing sleep and hydration is more impactful for sustained energy than rigidly timing a single cup of coffee.

• Manage Tolerance: Delaying morning caffeine might reduce overall dependence for some, but building a strategic routine is key.

The Origin of the 90-Minute Coffee Rule

The 90-minute coffee rule gained significant traction after being popularized by neuroscientist Dr. Andrew Huberman. His recommendation was to delay the first cup of coffee for 90 to 120 minutes after waking. This timing is based on a series of hypotheses concerning the body's natural physiological processes, aiming to provide a more sustained and productive energy boost throughout the day.

The Core Hypotheses Behind the Rule

The rationale behind delaying your morning coffee rests on three main biological claims:

• Cortisol Awakening Response (CAR): Upon waking, your body naturally experiences a surge in cortisol, a hormone that promotes alertness. Proponents of the rule suggest that introducing caffeine during this natural cortisol peak can blunt the effectiveness of both the body's internal wakefulness system and the caffeine itself. The idea is to let your body wake up naturally before adding a stimulant to the mix.
• Adenosine Theory: Adenosine is a neurotransmitter that builds up throughout the day, increasing "sleep pressure". When you sleep, adenosine levels clear out. The 90-minute rule theorizes that delaying coffee allows any remaining morning adenosine to clear naturally before caffeine blocks its receptors, leading to a more potent effect later on. When the caffeine wears off, the accumulated adenosine is released, causing the dreaded "afternoon crash". The rule suggests strategically timing your caffeine to use it most effectively.
• Reduced Dependence: It's argued that relying on an immediate caffeine fix can lead to increased dependency. By allowing the body to use its natural cortisol response first, the 90-minute rule could potentially reduce reliance on external stimulants and help maintain a healthier circadian rhythm.

The Science vs. The Hype: Debunking the Myth

Despite the viral nature of the 90-minute rule, recent research and expert opinions have brought its scientific foundation into question. Many of the core physiological assumptions have been challenged or disproven.

The Cortisol-Caffeine Contradiction

While caffeine does raise cortisol, for habitual coffee drinkers, the body develops a tolerance that significantly attenuates this effect. The idea that early caffeine harms your natural cortisol rhythm is largely unfounded, especially for those with a daily coffee routine. Furthermore, if avoiding cortisol spikes was truly the goal, regular morning workouts should also be avoided, yet they are widely endorsed for energy and metabolism.

The Misunderstood Role of Adenosine

Contrary to the rule's premise, adenosine does not decline for an extended period after waking; it is primarily cleared during sleep and begins to accumulate again upon waking. This means delaying caffeine does not allow for a more effective "clearance." In fact, some research indicates that caffeine is most effective at blocking adenosine receptors immediately after waking, making early consumption potentially better for reducing sleep inertia.

The Afternoon Crash: Is Timing Really the Cause?

The afternoon crash is a real phenomenon but is more likely a natural part of your circadian rhythm, independent of when you had your morning coffee. Factors like meal timing, hydration, and the total quantity of caffeine consumed are more significant contributors. For instance, a heavy, carb-rich lunch can cause an energy dip that is often blamed on an earlier cup of coffee.

What the Evidence Actually Suggests

So, if the 90-minute rule isn't scientifically sound, what does the evidence say about the best time to drink coffee? Ultimately, it's about individual physiology and listening to your body. There is no one-size-fits-all answer.

Here are some factors to consider:

• Individual Tolerance: Genetics and habitual intake play a huge role in how quickly you metabolize caffeine and how sensitive you are to its effects. Some people can drink coffee late with no issue, while others need to cut off intake early in the day.
• Sleep Quality: Consistent sleep habits are the most powerful regulator of adenosine. The best way to reduce morning grogginess is to get a full, restorative night's sleep, which resets adenosine levels.
• Meal Timing: The body's natural energy peaks and dips are significantly influenced by meals. Pairing coffee with food can smooth out caffeine's release and prevent discomfort, especially for those sensitive to caffeine on an empty stomach.

Comparison: 90-Minute Rule vs. Personalized Timing

Feature	90-Minute Rule	Personalized Timing Approach
Basis	Viral wellness advice based on flawed scientific claims about cortisol and adenosine.	Individual observation of one's own energy levels and caffeine metabolism.
Effectiveness	Highly debated and likely ineffective for most habitual coffee drinkers.	More reliable for achieving consistent energy and avoiding crashes by aligning with personal biology.
Cortisol Interaction	Aims to avoid cortisol peak, but this effect is minimal for regular consumers.	Acknowledges that caffeine's effect on cortisol varies by individual tolerance.
Adenosine Clearance	Based on the false premise that adenosine levels decline after waking.	Respects that adenosine builds throughout the day and is primarily reset by sleep.
Caffeine Crash	Attributes crashes to early timing, but other factors are more significant.	Links crashes to total intake, meal timing, and individual response.
Ease of Adoption	Simple, but potentially rigid and unnecessary.	Requires self-monitoring but leads to better, long-term results.

Finding Your Personal Optimal Coffee Time

Instead of adhering strictly to a debunked rule, a more effective strategy is to become a student of your own body. Here's how to develop a personalized, productive coffee routine:

• Observe Your Energy: Take a few days off caffeine if possible, or at least monitor your energy patterns without it. When do you feel naturally alert? When do you typically experience a slump? Use a journal to track these patterns.
• Test and Adjust: Try having your coffee at different times. Maybe your ideal window is indeed mid-morning, after your natural cortisol peak. Or perhaps you feel best having a small cup shortly after waking to combat sleep inertia. Experiment with timing your consumption to hit a peak before a critical task or meeting.
• Consider Quantity: Spreading smaller doses of caffeine throughout the morning rather than consuming a single large dose can help prevent sharp energy spikes and subsequent crashes. Many people also find that a pre-lunch cup of coffee is the perfect way to get through the mid-afternoon dip.
• Set a Cut-Off Time: To protect your sleep, establish a cut-off time for caffeine, typically 8-10 hours before bed, as caffeine's half-life can be long.
• Stay Hydrated: Always pair your coffee with plenty of water, as dehydration can exacerbate fatigue and jitters.

For a deeper dive into the science of how caffeine affects the body, explore this publication: Pharmacology of Caffeine - NCBI.

Conclusion: Is the 90 minute coffee rule true?

The simple answer is no. While the 90 minute coffee rule is a compelling biohacking concept, its underlying scientific assumptions regarding cortisol and adenosine are largely contradicted by evidence. Most studies suggest that the optimal timing for caffeine is highly individualized and depends on personal genetics, tolerance, and lifestyle. Instead of blindly following a viral trend, the best approach is to listen to your own body. By observing your natural energy cycles and strategically timing your coffee consumption, you can truly harness caffeine as a tool for sustained energy and productivity, without the unnecessary crashes or disrupted rhythms that the rule claims to fix.

Recommended Morning Routine

1. Hydrate First: Drink a glass of water to rehydrate your body after sleep.
2. Get Some Sun: Expose yourself to natural light for 10-15 minutes to help regulate your circadian rhythm.
3. Wait and Observe: Wait an hour or two and take note of your natural energy levels.
4. Enjoy Your Coffee: Have your coffee when you feel your natural alertness dipping, not necessarily at the absolute first moment you are awake. For many, this is mid-morning.
5. Eat Well: Pair your coffee with a balanced breakfast to prevent crashes and digestive discomfort.
6. Stay Hydrated: Continue drinking water throughout the day.
7. Consider Decaf: Opt for decaf in the afternoon if you are sensitive to caffeine.
8. Set a Cutoff Time: No caffeine for 8-10 hours before bed.

Frequently Asked Questions

Who popularized the 90 minute coffee rule?

The 90-minute coffee rule was popularized by neuroscientist Dr. Andrew Huberman, who suggested delaying caffeine intake to work with the body's natural cortisol cycles.

Is the 90 minute coffee rule scientifically proven?

No, scientific evidence contradicts the core premises of the 90-minute rule. Research shows that habitual caffeine drinkers develop tolerance to its effects on cortisol and that adenosine levels actually begin accumulating after waking, not clearing.

Does drinking coffee immediately after waking affect cortisol?

While caffeine can briefly increase cortisol, the effect is minimal and often tolerated by regular coffee drinkers. The theory that early coffee disrupts the natural cortisol awakening response is largely unfounded.

What is adenosine and how does it relate to coffee?

Adenosine is a neurotransmitter that promotes sleepiness, increasing throughout the day. Caffeine works by blocking adenosine receptors. The 90-minute rule incorrectly claims that adenosine clears naturally after waking, making a delayed coffee more effective.

What actually causes the afternoon coffee crash?

The afternoon crash is a natural part of the circadian rhythm and is more influenced by factors like meal timing, hydration, and overall sleep quality, rather than when you drank your morning coffee.

What is the best time to drink coffee for lasting energy?

The best time is highly individual. Mid-morning (9:30-11:30 a.m.) is often cited as a good window as natural cortisol dips. However, listening to your body and experimenting with timing is key.

How can I reduce my reliance on morning coffee?

Instead of rigidly following a rule, focus on improving overall sleep quality, exposing yourself to natural morning light to regulate your circadian rhythm, staying hydrated, and timing your coffee strategically for your most effective work periods.