Does caffeine work?


in Daily updates, Geek stuff, Internet matters, Psychology, Science

You Are Not So Smart is a blog that seeks to catalog the many mental failings of human beings: from the confirmation bias to our ignorance about our past beliefs.

In one post, they argue that caffeine (coffee, specifically) mostly just alleviates caffeine withdrawal. Rather than lifting you up from ‘normal’ to a more wakeful state, it just brings you back to normal, from the depressed state that caffeine consumption establishes as your new norm:

The result is you become very sensitive to adenosine, and without coffee you get overwhelmed by its effects.

After eight hours of sleep, you wake up with a head swimming with adenosine. You feel like shit until you get that black gold in you to clean out those receptor sites.

That perk you feel isn’t adding anything substantial to you – it’s bringing you back to just above zero.

Neurologist Stephen Novella echoes this position on his blog:

The take home is that regular use of caffeine produces no benefit to alertness, energy, or function. Regular caffeine users are simply staving off caffeine withdrawal with every dose – using caffeine just to return them to their baseline. This makes caffeine a net negative for alertness, or neutral at best if use is regular enough to avoid any withdrawal.

As an experiment, I am going to try abandoning caffeine for a week or so. I will report on any notable effects, though it is always hard to determine which observed changes in ones mental life are the consequence of any particular change in circumstances, given all the complexities of life and all the failings of our mental faculties.

{ 29 comments… read them below or add one }

EK July 6, 2010 at 9:57 am

Hurray! I love tests like this! So fun. Keep us posted.

For reference, how much caffeine do you currently have in a day?

Milan July 6, 2010 at 10:03 am

Ordinarily, I would guess about 600-800mg per day, during the week.

That’s about 400mg in a morning Venti coffee, and another 200-400mg over the course of the day, from other sources.

This morning, I definitely feel a bit as though I have a “head swimming with adenosine.”

Tristan July 6, 2010 at 10:16 am

Even if caffeine produces no benefit to alertness, I still think coffee is wonderful.

R.K. July 6, 2010 at 10:53 am

It is probably asking too much to expect caffeine (or any other psychoactive drug) to keep working even when you use it every single day.

Our brains seem to naturally become less sensitive to most drugs, when constantly exposed.

Matt July 6, 2010 at 12:00 pm

As someone who doesn’t drink caffeinated drinks, and probably consumes very little from other sources (to the best of my knowledge), I’ve always secretly wondered about this.

Having said that, I’ve seen reports on other studies that mention some net benefits to moderate caffeine intake, ie. positive mental effects, reduction of incidences of Alzheimer’s, etc. That’s when I feel like I’m missing out.

Alex July 6, 2010 at 1:02 pm

Very interesting. I only started drinking coffee on a regular basis at the age of 22 before arriving in Oxford. While I now find it very difficult to go through a regular working-day without at least three cups of coffee or espresso, I managed just fine before. This is why the thesis makes intuitive sense to me.

Milan, have you not tried giving up coffee before? Why did it not work? I wonder whether former coffee-addicted people could share any “best practices” about how to best give up coffee (if I ever decided to do so).

Milan July 6, 2010 at 2:37 pm

This is about the time of day when I would normally have a second dose of caffeine. I am certainly feeling a craving and lack of wakefulness, despite a good night’s sleep yesterday.

Byron Smith July 7, 2010 at 1:37 pm

Apart from loving the occasioanal chocolate, I’ve never enjoyed any caffeine products. Stories like this confirm my distaste. Looking forward to hearing about your experiment. Any ideas how long it takes for your body to fully recover from a caffeine addiction?

Milan July 7, 2010 at 1:39 pm

Web sources suggest 9+ days.

I am definitely feeling rather tired today, despite sleeping for an unusually long span last night and the night before.

. July 7, 2010 at 2:33 pm

The Misconception: If you stop engaging in a bad habit, the habit will gradually diminish until it disappears from your life.

The Truth: Any time you quit something cold turkey, your brain will make a last-ditch effort to return you to your habit.

Once you become accustomed to reward, you get really upset when you can’t have it.

. July 7, 2010 at 4:49 pm

Withdrawal symptoms — possibly including headache, irritability, an inability to concentrate, drowsiness, insomnia and pain in the stomach, upper body, and joints — may appear within 12 to 24 hours after discontinuation of caffeine intake, peak at roughly 48 hours, and usually last from one to five days, representing the time required for the number of adenosine receptors in the brain to revert to “normal” levels, uninfluenced by caffeine consumption. Analgesics, such as aspirin, can relieve the pain symptoms, as can a small dose of caffeine. Most effective is a combination of both an analgesic and a small amount of caffeine.”

Jonathan July 7, 2010 at 10:52 pm

To be clear, I am fully aware of my massive caffeine addiction and the fact that I mostly need caffeine to alleviate the symptoms of withdrawal… which it does.

I count this as caffeine working. :)

oleh July 8, 2010 at 9:20 pm

Milan, how is it going so far after 48 hours?

Milan July 8, 2010 at 9:23 pm

All day, I had less energy than usual and a bit of a headache.

Nothing serious though.

Ryan Nassichuk July 11, 2010 at 7:41 pm

I’ve quit drinking coffee about ten times since starting at the age of twelve. The last time I quit, I tapered by reducing my dose by eight beans every day (I grind my own). By the time I got to around twenty beans in a cup, I stopped – It was a very weak cup.

All the other times I’ve quit, I’ve felt like garbage for about a week.

I’m drinking a cup right now – In addition to being wonderful in every way, coffee helps with my hay fever, and doesn’t make me hallucinate like many of the drugs marketed for that purpose.

Milan July 12, 2010 at 8:20 am

I think I am already feeling benefits from this decaffeination approach. I think I am nearing the point where I am as awake all the time as I used to be only after drinking coffee.

. July 14, 2010 at 4:24 pm

What Caffeine Actually Does to Your Brain

Right off the bat, it’s worth stating again: the human brain, and caffeine, are nowhere near totally understood and easily explained by modern science. That said, there is a general consensus on how a compound found all over nature, caffeine, affects the mind.

Every moment that you’re awake, the neurons in your brain are firing away. As those neurons fire, they produce adenosine as a byproduct, but adenosine is far from excrement. Your nervous system is actively monitoring adenosine levels through receptors. Normally, when adenosine levels reached a certain point in your brain and spinal cord, your body will start nudging you toward sleep, or at least taking it easy. There are actually a few different adenosine receptors throughout the body, but the one caffeine seems to interact with most directly is the A1 receptor. More on that later.

Enter caffeine. It occurs in all kinds of plants, and chemical relatives of caffeine are found in your own body. But taken in substantial amounts—the semi-standard 100mg that comes from a strong eight-ounce coffee, for instance—it functions as a supremely talented adenosine impersonator. It heads right for the adenosine receptors in your system and, because of its similarities to adenosine, it’s accepted by your body as the real thing and gets into the receptors.

More important than just fitting in, though, caffeine actually binds to those receptors in efficient fashion, but doesn’t activate them—they’re plugged up by caffeine’s unique shape and chemical makeup. With those receptors blocked, the brain’s own stimulants, dopamine and glutamate, can do their work more freely—”Like taking the chaperones out of a high school dance,” Braun writes in an email. In the book, he ultimately likens caffeine’s powers to “putting a block of wood under one of the brain’s primary brake pedals.”

It’s an apt metaphor, because it spells out that caffeine very clearly doesn’t press the “gas” on your brain, and that it only blocks a “primary” brake. There are other compounds and receptors that have an effect on what your energy levels feel like—GABA, for example—but caffeine is crude way of preventing your brain from bringing things to a halt. “You can,” Braun writes, “get wired only to the extent that your natural excitatory neurotransmitters support it.” In other words, you can’t use caffeine to completely wipe out an entire week’s worth of very late nights of studying, but you can use it to make yourself feel less bogged down by sleepy feelings in the morning.

Milan July 16, 2010 at 4:11 pm

I didn’t get much sleep last night, and had a fair bit to get done this afternoon. As such, it seemed like a good time to check whether my caffeine holiday has re-sensitized my brain to the drug.

With a venti bold distributing itself through my blood, I can report emphatically that it has. It took me from being tired to the point of serious underperformance to being able to function modestly better than normal.

Of course, I will have to take a break from caffeine during the next few days, so as to avoid getting back into a situation of dependence.

R.K. July 20, 2010 at 5:48 pm

Punctuated abstinence seems the correct policy.

. December 5, 2010 at 10:17 pm
Alex December 7, 2010 at 11:59 am


Are you still abstinent? I ended up following your experiment in the summer. I experienced all the symptoms for the first week and felt much better the second week. The third week I ended up drinking coffee again. Now I firmly find myself in the coffee dependence cycle which is so nicely summarized in this chart.

Milan December 7, 2010 at 12:22 pm

I also had success with abandoning caffeine, then went back to using it. I am using it a lot lately.

The clarity of thinking it can provide is really useful and enjoyable – even if it increases how much time I actually spend feeling tired, all in all.

Matt December 7, 2010 at 12:25 pm

Isn’t that clarity of thinking, according to the original post, just your baseline?

Milan December 7, 2010 at 10:12 pm


It does seem plausible that for those who aren’t already caffeine-saturated, drinking coffee can boost mental acuity above the baseline level. I doubt it still does that for me now, though.

. January 27, 2011 at 8:08 pm
. September 10, 2012 at 12:06 pm

“Does coffee improve performance?

It’s difficult to be sure whether coffee actually improves performance. Most of us are physically dependent on it, going into withdrawal overnight, and withdrawal impairs performance. If a coffee drinker does better on a task after having some caffeine it’s difficult to know whether this is a genuine improvement or just compensating for the impairment they experienced before they had their caffeine fix (ie not a positive factor, just the removal of a negative factor). This theory is supported by research which has found that caffeine improves performance more in people who are coffee drinkers than those who normally don’t consume caffeine at all. On the other hand, caffeine certainly does have effects in itself – researchers use it to model insomnia when they’re testing sleeping pills, for example – so it’s possible it does provide a mild cognitive advantage.”

Nutt, David. Drugs Without the Hot Air: Minimising the Harms of Legal and Illegal Drugs. p.243 (paperback)

Milan September 10, 2012 at 1:43 pm

Given this, I am going to taper off my caffeine use. I will cut it back to one cup of coffee per meal, at the Massey dining hall only. When I am used to that, I will cut down to 2 meals or just breakfast.

anon June 15, 2013 at 3:02 pm

A Coffee Withdrawal Diagnosis

Quitting Caffeine Is Now Listed as a Mental-Health Disorder; The Best Ways to Break the Habit

Caffeine intoxication was included as a diagnosis in the previous version of the manual, known as DSM-IV. But caffeine withdrawal was upgraded in the current manual to a diagnosis from a “research diagnosis” previously, meaning it required further study for inclusion. Also, caffeine use disorder—when a person suffers troubling side effects and isn’t able to quit—was added to the current manual as a research diagnosis.

Milan September 26, 2015 at 8:18 pm

One reality of modern life that has impressed itself on me is how large a fraction of the population is inhabiting a polydrug landscape at any particular time.

Every drug takes some amount of time to be eliminated from your brain and body. Also, since psychoactive drug use changes the function of your brain, there is a longer period before your brain returns to how it was before the drug was consumed. I have heard that the full effects of consuming alcohol take about three days to go away.

So consider people who regularly consume caffeine, sometimes consume alcohol, may be on psychologically active prescription drugs, may use psychologically active recreational drugs, etc. These people are in an ever-changing landscape where they are experiencing brain chemistry effects from the presence of some substances and the absence of others all the time. The impossibility of isolating any single variable in this sort of situation means they cannot experiment meaningfully with what any single substance is doing to their minds.

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