Whenever I drink the first coffee in the morning, initially I get energized from it. However if I go for a second one right after, or even wait a while, I don't get the same rush.

How long should I wait between each coffee drink so I can get the same buzz? Is there an equation for this?

2 Answers 2


I don't know that this is a standard time period.. Honestly, the more coffee you drink, the less you are going to get the 'buzz' going. A lot of this depends on your body type, activity level, and genes.

You have to think of caffeine like a drug, because that is what it essentially is. When you take your first sip of coffee, it takes about 45 minutes for 99% of the caffeine to be absorbed by your system. The caffeine has a half life of roughly 4-6 hours in the human body. That buzz you are feeling is because as you have slept, all of the caffeine in your system has been depleted and thus when you get that first cup in the morning, your system gets a big blast of caffeine after not having any.

Here's a pretty interesting article that contains a lot of the information I just parroted above (plus quite a bit more):

Caffeine Metabolism

  • I remember that I did the math once for the toxicological effect of caffeine. However, I cannot put my finger on the exact source, now. In short, it was something like that: one cup every two minutes for 24 hours could poison you to death. Note that, the calculation is only by caffeine. You might probably die by something else before this time span if you try that at home. :)
    – MTSan
    Jul 4, 2017 at 14:02
  • 1
    @MTSan - just the liquid alone may kill you. At 5oz per cup * 30 * 24 = 3600 oz (or 28 gallons) which is far above the daily recommendation of 64 oz of water per day.
    – Mayo
    Jul 5, 2017 at 13:09
  • @Mayo The source is, for sure, Coffee SE. :) I just stumbled upon. coffee.stackexchange.com/questions/2857/…
    – MTSan
    Oct 23, 2017 at 21:01

The mean half life of caffeine varies considerably but is approximately 5 - 6 hours. What this means is that an average person's body will get rid of half of the buzz producing caffeine in about 6 hours.

So theoretically if you sip each subsequent cup over a six hour period you'd keep the buzz almost constant. That isn't a very practical approach for most people but drinking a cup of coffee every three to four hours would be a reasonable approximation.

This situation is referred to as steady state pharmocokinetic modeling. You can find the basic equations here.

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  • This is excellent
    – EconJohn
    Apr 16, 2018 at 2:44

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