How does caffeine actually work? Why do people get even more tired after they stop using it after a while?



How does caffeine actually work? Why do people get even more tired after they stop using it after a while?

In: Biology

So caffeine is a pretty interesting drug. It has mildly stimulating effects, but what it’s actually known for is it’s ability to block sleep. These are not the same thing. Drugs like amphetamine and cocaine boost neurotransmitters. However, caffeine actually *blocks* certain compounds from working right. The most notable is adenosine. One of adenosines functions is to induce *sleep pressure*, basically the fancy term for feeling tired. Caffeine is an antagonist of this, so you have that 32oz cold brew and 30 minutes later sleep is the last thing on your mind. But the thing is, the adenosine didn’t go away, it just sort of got locked out; temporarily. Eventually, the warriors of the caffeine tribe are overpowered by the adenosine, and caffeine can no longer hold the line, and you know what happens: you *CRASH.*

Of course, the simplest and perhaps most effective quick solution? Have more caffeine! And it works…sort of. The problem is, your physical body is a lot smarter than you think. It quickly begins *upregulating* adenosine receptors. It would be like, if you had a wild nightclub with 3 main doors, and the arrogant fuck bouncers called caffeine kept blocking all the clubgoers out every night until 3am, one of the ways that you could strategically weaken the bouncer position is to simply start breaking more doors into the side of the club. This is basically an ELI5 of what receptor upregulation is. Your brain has been ‘trained’ to handle an adversary, caffeine. And that is what it is, to your brain, it’s not your friend; it’s preventing it’s nightclub from functioning right.

Now, all of a sudden, you have 30 doors when you used to have 3, so fuck man, you suddenly realize you need a LOT more caffeine to wake up. Well, no kidding. You have a LOT more points of entry to ‘defend’. And thus, 1 cup becomes 2…3..4..before you know it, you’re snorting coffee grinds off of the floor at a Starbucks in downtown Albany and blasting Black Stone Cherry, Buckcherry, and Black Label Society albums out of your ’95 Ford Windstar and making random trips to weird ass apartment complexes in Schenectady. But that’s not the worst part.

The worst part, by far, is when you decide to abandon the position. You say, *fuck this,* I am done with caffeine. And one day, you just stop. Well, your nightclub originally had 3 entry points. Now it’s got like….50. And all that adenosine that’s been expecting the daily fight with caffeine suddenly find the place is wide open. No bouncers. What?! And man, it’s like a scene from Studio 54. Every adenosine in the city jumps through every god damn opening in that building. No rules! Anything goes! It’s complete debauchery and partying!

If you recall, adenosine builds sleep pressure. So, what used to feel like 3 ‘sleep pressures’…now feels like 50. *Caffeine withdrawal* has started.

That is seriously how this stuff happens. Eventually, if you keep caffeine away, the walls of the building are repaired and patched up. And eventually, adenosine can gain some more control over it’s devious partying and bring it’s level back down to 3-door level instead of 50. But, rest assured, if you drink caffeine again, your nightclub will recognize those assholes called caffeine much faster – and the doors will break open again to let adenosine back in. This is truly how addiction recovery from caffeine spells itself out. Anyone who’s ever abstained from caffeine for a few weeks and then decided to go back to it will feel it tremendously amplified, for at least a few days. But very quickly, the old ways start again, and you need more to get the same energy.

To sum it up, this is why stimulants and caffeine, without a doubt, work best when they are used as needed, and not every day. The general idea is to keep the adenosine unsure of when caffeine will show up. A related aspect is also that of *minimal effective dose*. Recall that the nightclub goers (adenosine and the club itself) will start breaking holes in the wall to get in – but what if we sort of taunt adenosine with caffeine, instead of just bombarding it with the stuff? Well, maybe they won’t break down the walls so aggressively. This is also very true, in huge aspects of psychopharmacology; that is to say, in many cases, less is more. *Use sparingly* and in *low to moderate doses.* That’ll keep those adenosines on their toes. Hope this helps.

By the way, for the “real” stimulants, such as amphetamine (Adderall), methylphenidate (Ritalin), cocaine, meth, etc, all of this is very similar, however, it’s sort of in *reverse*. In this case, dopamine, norepinephrine, and serotonin are trying to *stay in* the club, but they gotta take a piss outside; and once these drugs see them leave the club, they lock them out and throw them to the bar across the street, which always gets the party started. In some cases, like with amphetamine, not only are the club goers locked out of the club and told to party at the bar, but some are *forced* out! Meanwhile, across the street, the bar is nice and orderly, but it’s starting to get a little amped up. It starts ok, but eventually the bartender is basically like, *what the fuck, nightclub?! Get your drunken neurotransmitters OUT OF HERE!* and BLOCKS some of his doors in an effort to keep the party from getting absolutely out of control. This is downregulation, whereas in the previous example, it was upregulation.

Just remember that word, homeostasis. The brain/body/biology, etc. is always trying to maintain a balance. And by the way, not all of this stuff is “bad”, some of these things have absolutely incredible therapeutic benefit for the right reasons to the right people. Some people’s ‘bars’ are really sad and lonely, and so specific bouncers can lock out certain neurochemicals, like serotonin, so they have a better chance of going into the bar and cheering it up (clinical depression). Or perhaps some people’s bar can’t get it’s shit together on it’s menu. Some bouncers can lock dopamine out of the club, and when it goes into the bar, it can kick the writers and line cooks into shape and get your shit organized (ADHD), etc. Some drugs do the *opposite*, and maybe throw dopamine out of *the bar* because the party is completely out of control; the cops, basically (antipsychotics). This is why, for instance, if one takes WAY too many stimulant drugs, they can sort of enter a temporary state of psychosis. They’ve basically overwhelmed the bar.

This stuff is sort of a gross oversimplification, BUT it is important to understand on a basic level what is going on. As many could probably guess, psychopharmacology and neurochemistry is an extremely complex and dizzyingly deep topic, and to make it even worse, we still don’t *really* know a lot about what goes on in the brain. There are entire aspects of this that I intentionally left out, for example, some people are genetically disposed to be able to break down caffeine, or not break down caffeine. Some people have genes that allow or disallow them to actually even feel effects of certain stimulants ([look up rs4680 on Google]( But – the fundamentals; the movements of chemicals and the bodies responses to them over time, are actually pretty straightforward. It is a very exciting time to be alive, as we discover more and more about our brains each day – the organ that defines our realities.



edit: I still can’t spell.

Shorter version of the wall of text:

Caffeine blocks a chemical in your head that tells you you’re tired. It fills the parking spot in a neuron this chemical normally uses, so until it wears out, you will artificially not feel tired.

As times goes on, more receptors of the tiredness chemical are made available, more caffeine is needed to block them and eventual withdrawl causes much more of the tiredness signaling chemical to be applied at once.

Your body builds up a tolerance to any thing you dump into your system. Not necessarily a healthy thing. But your body is always trying to counteract the bad you bring in to it. Caffeine simulates you. Your body had its own natural stimulants. After a while, your body gets used to the added stimulants and simply reduces the natural amount. So when you stop the caffeine, you’re now running on less than before.