Cup of spilled coffee beans

How Does Caffeine Work: The Science Behind Coffee Magic

January 06, 2021

If you still want to believe in coffee magic, leave this article and go straight to your next cup of Fire Dept. Coffee. We wouldn’t want to ruin this for you!

However, if you’re really interested in coffee science and are still wondering ‘how does caffeine work?’, keep reading.

We’re about to let you in on the secret, dissecting what seems like a complicated topic in a friendly, jargon-free way.

Grab a fresh pot and let’s start this coffee science lesson!

What is caffeine exactly?

Coffee plant showing where caffeine is found in nature

Simply put, caffeine is a natural stimulant found in the leaves and fruits of some plants.

Obviously, you’ll find it in coffee beans but also in tea leaves, guarana seeds or yerba mate, as well as in products like cola, energy drinks and even chocolate. 

By ‘stimulant’, we mean a substance that increases neural activity in your brain by speeding up the central nervous system. 

How? Let’s start from the beginning!

How does caffeine work in the body?

Working professional relying on the effects of caffeine

After you drink a delicious cup of coffee, caffeine enters your body. 

It’s usually absorbed within an hour, accessing more parts of your system through your bloodstream.

Blood concentration usually peaks within two hours. When it gets to your brain, that’s where all the magic (or coffee science, depending on how you decide to look at it) happens.

How does caffeine work in the brain?

Coffee cup with the words 'My brain needs more caffeine'

The way caffeine works in the brain is actually a pretty crazy but fortunate coincidence: this natural stimulant just happens to have a similar structure to our adenosine.

Normally, adenosine locks to some specific receptors in our brain, slowly promoting sleepiness and muscle relaxation.

However, guess what happens when you drink coffee? Yep. 

Just like that time you mistakenly added salt instead of the similar-looking sugar to your drink, it’s caffeine that heads towards those receptors.

So how does caffeine work in the brain? It simply gets in the way of adenosine, stopping that tired and sleepy feeling. 

Instead, it promotes the activity of other neurotransmitters like dopamine, which leads to the opposite effect: heightened brain activity.

So, how does caffeine keep you awake?

Alarm clock next to a bed before breakfast to symbolize how caffeine keeps you awake

Basically, caffeine keeps you awake by slowing down adenosine (responsible for provoking that sleepy feeling) and promoting the release of dopamine instead.

However, like Cinderella taught us, magic doesn’t last forever. After an average of five hours, the carriage turns back into a pumpkin: caffeine’s effect ends and adenosine prevails. 

If this happens abruptly, you can even get a caffeine crash (psst: here’s how to avoid one!)

Caffeine’s effects: a more or less scientific explanation

Caffeine is actually the main reason behind the most popular benefits of drinking coffee.

Even before knowing how caffeine worked, you’ve probably already noticed its results. 

For example:

  • Energy boost and a feeling of being invincible;
  • Typing faster than Jim Carrey in Bruce Almighty;
  • Mental boost and being able to recognize your boss’s steps when they’re coming to check on you;
  • Finding the strength to endure long shifts;
  • Managing to feel hopeful even on a Monday morning.

So how does caffeine work? Scientifically, it fights against adenosine. 

At our fire station? It gives us superpowers. Which, to be honest, is not that far from the truth.



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