The Best Time Of The Day To Consume Caffeine

Written by: Garrett Oden

best time of the day to consume caffeine

If you’re like me, coffee is the true alarm clock. The annoying ringing from my phone is just the appetizer, the rich mug of coffee is the full wakeup meal.

I can hardly think clearly without my morning mug. I’m sure you know what I’m talking about.

But, despite my body’s morning craving, that early cup isn’t actually the ideal time to drink coffee. In fact, it’s one of the worst times.

That’s right. Rolling out of bed and walking straight to the coffee maker isn’t very healthy for you. I first read this years ago when a blog by neuroscientist Steven L. Miller was published.

And I was shocked.

I didn’t want to believe it, but you can’t fight good science. As time goes on, more research proves what Dr. Miller once claimed (to the chagrin of many): first-thing in the morning coffee isn’t ideal.

For this blog, we’ll look not only at that early morning cup, but coffee for the whole day. We’ll discuss the best time of the day to consume caffeine - as well as the worst.

Let’s begin by taking a look at Miller’s unpopular (yet scientifically proven) claims.

Early Morning Coffee Is Not Ideal

Steven Miller is currently a post-doctoral researcher at the Geisel School of Medicine at Dartmouth. One of the things he studies is Chronopharmacology, the study of how drugs interact with your body’s natural rhythms.

In this scenario, we’re talking about your biological clock - the circadian rhythm.

Read: Skip The Coffee Aisle, Here's How To Find The World's Best Coffee

Your circadian rhythm runs on a rough 24-hour clock and is regulated by your environment. Daylight, for example, is a heavy regulator of this rhythm. When the sun’s out, you feel awake and alive. When it’s cloudy, you feel more slow and lazy.

Sleep schedule, hunger, and many other things are determined by this clock, including your body’s hormone production schedule.

When you first wake up, your circadian rhythm orders the production of cortisol. Cortisol is commonly known as the “stress steroid” because it often shoots up in concentration when you’re stressed or have an adrenaline jump. Cortisol brings you to alertness, wakes you up, and manipulates many biological processes.

Everyone experiences natural cortisol boosts throughout the day, with a daily peak between 8 and 9 AM for most people.

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This means that caffeine consumed during this time is largely wasted because you’re already at your natural alertness peak (even if you don’t always feel like it).

Read: Learn To Taste Coffee!

When you drink coffee between 8 and 9 AM, your body consumes the caffeine, doesn’t end up needing it, but still develops a tolerance.

You’re likely to develop a caffeine tolerance no matter when you drink coffee, but here’s the thing:

  • In this case, you’re building a tolerance with a very low boost
  • In other words, you’re paying the same tolerance dollars but getting very little back
  • If we’re talking about a return on investment, it’s a bad one

Eventually, you’ll need more and more coffee to achieve the same small effect. This is why the period between 8 and 9 AM is the worst and least effective time to drink your morning mug.

What If You’re An Early Riser?

Wake up well before 8 AM most days? I’ve got information for you as well.

Miller, in a later interview with Military Times, broke down pre-sun cortisol production to answer this question.

Essentially, there’s what’s called a “Cortisol Awakening Response”, which happens no matter how bright it is outside. Even if you wake up before sunrise, you experience a 50% boost in cortisol production.

Read: Why Fresh Coffee Is The Best Coffee

So, while a very early mug may help somewhat with waking up, it’s still not a very efficient time to consume caffeine. You’re better off waiting for a few certain periods, which I’ll tell you about in just a moment.

best time of the day to consume caffeine

Afternoon Cortisol Peaks

According to Miller, 8 AM to 9 AM is the most dramatic cortisol peak - but it’s not the only one.

Smaller peaks happen again between 12 and 1 PM, and again from 5:30 and 6:30 PM.

Once again, these are times where your caffeine intake will be largely wasted energy-wise. It doesn’t mean the coffee won’t be delicious and rewarding. It just means you’ll build up your tolerance for very little gain.

Read: Is Pour Over Coffee Brewing Worth The Effort?

The Best Time Of The Day To Consume Caffeine

Let’s finally get to the part that really matters: the best time to drink coffee and consume caffeine. Miller claims that this point is immediately after a cortisol peak.

So in the morning, 9 to 11:30 AM.

In the afternoon, between 1 and 5 PM.

These periods between natural cortisol boosts are the times where that caffeine jolt will be most productive. Instead of crashing between peaks, you’ll maintain alertness.

A mug of coffee after 6:30 PM will help you avoid another crash, but you run into some other problems.

Evening Coffee And Your Sleep

There is no disagreement in the scientific community that caffeine at night can destroy your quality sleep. The topic is widely explored and the effects are clearly documented.

Here are a few science facts to consider:

  • Late night coffee delays melatonin production, the circadian rhythm hormone that helps you fall asleep and wake up
  • According to one study, caffeine even 6 hours before sleep often knocks 1 hour off your total sleep time

It’s difficult to experience uninterrupted, deep sleep with caffeine in your body. Even when you think it’s not affecting you - it is. Incorrect perceptions on how much coffee affects your sleep are also well documented.

However, not everyone agrees on how late is too late for coffee.

I cannot say exactly when you should make a clean break from caffeine at night, but for most of us, 5 PM is a safe cut-off, if not a bit earlier.


Let’s again review the best and worst times to drink coffee and consume caffeine:

  • Before 8 AM: Not Ideal
  • 8 AM to 9 AM: Bad
  • 9 AM to 11:30 AM: Good
  • 12 PM to 1 PM: Bad
  • 1 PM to 5 PM: Good
  • After 5 PM: Bad

Enjoy your coffee responsibly, and it’ll give you the right boosts at the right times. And, of course, don’t settle for coffee that you don’t love.

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