Science Questions

Can I reset my tolerance for caffeine?

Sun, 18th Nov 2012

Listen Now    Download as mp3 from the show Can Gravity Leak from Alternate Universes?


Ari Huttunen asked:

Hello Naked Scientists!


My name is Ari and I'm a plant pathology student in Helsinki University, Finland. My boring summer job has allowed me to listen to your splendid podcasts and I usually listen to three shows per day.


My question concerns caffeine tolerance. When you drink loads of coffee on a daily basis, eventually you become tolerant to caffeine and you need more coffee to stay alert at lectures or seminars. At least according to my experience. Just as curiosity, do you think it would be possible to switch off or reset the acquired tolerance by some feat of biochemistry in the brain? Personally I would refrain to dope my head with too much stimulants and take a break from coffee for a few days - if possible that is.


Love to hear your thoughts on this! Thank you for a great show and inspiring my scientific thinking.




Ari Huttunen



Ginny -   Caffeine is used by so many people to keep them feeling awake.  Itís probably one of the most commonly used drugs, but it actually works by countering a substance in your brain known as adenosine.  This builds up during the course of normal brain activity.  There are receptors to monitor the amount of the substance and thatís how your brain tells when itís coming to the end of the day, and you should maybe be getting a bit sleepy and thinking about going to bed.  

Now caffeine is really clever because it looks quite similar to one of these adenosine molecules so that it actually fits into the receptors, but doesnít activate them.  

So because the receptors are then blocked by the caffeine molecules, your brain is tricked into thinking there's less adenosine there and so, you donít get the feelings of sleepiness and that allows your brainís natural stimulants, the dopamine and glutamate molecules to work freely without being inhibited.  

The strength of these effects can vary from person to person and it depends on loads of different factors, but partly, itís their level of tolerance.  As with all drugs, continued use of caffeine does build up this tolerance.  So, the first time you have a cup of coffee, you probably feel its effect very strongly, but if youíve been drinking 5 cups a day for 10 years, you'll probably stop feeling the effects at all and actually, just need it to get back to a normal level.  You can think of tolerance as the brain trying to get back to what it was like before you started drinking caffeine.  So, if you push it in one direction, itís going to try and push back in the other direction.  But that then means if you take away the caffeine, your brain is then too far the other way and this is where you get the withdrawal symptoms which can be quite extreme.

Chris -   Headache.

Ginny -   A lot of people get headaches, but you can also get nausea, you can get irritability, all sorts of horrible things.  This tolerance can build up really quickly, actually between 1 and 2 weeks and can be really strong.  So, even very high doses of caffeine can start not increasing your alertness after only 18 days or so.

Chris -   There was a chemist in Glasgow University who did a study where he wants to know how much caffeine was in the coffees being served up at the average coffeehouse.  If you go and buy a pack of cigarettes for example, they tell you how much nicotine there is in cigarettes.  If you go and buy an alcoholic drink, it would tell you how much alcohol there is in it.  You can go to any coffee chain and buy a coffee, but it doesnít tell you how much caffeine is in there.  

This is important because there are risks to health for certain groups.  Women who are pregnant Ė itís been shown Ė should probably try to keep their caffeine intake down below about 2 cups a day because any more than that can actually be associated with miscarriage.  

And this gentleman found, by going into a number of Ė I think more than 20 - coffee shops in Glasgow, ordering an espresso and then immediately taking it outside, putting it in methanol and then freezing it in his lab to preserve the caffeine, he found that there was anything between 50 micrograms of caffeine which is the equivalent of a reasonable strength coffee up to 300 from one coffee shop!  So thatís the equivalent in just the same beverage of having 6 cups of coffee in one go from one store and just three in another.  Itís amazing, isnít it?  Itís incredible dosage!

Ginny -   Wow, thatís a huge difference.

Chris -   So what should Ari do then?  Should he ditch the coffee?

Ginny -   Well sadly, the only way to get over this tolerance that I've found is to stop drinking the coffee.  There are people who say itís better to go cold turkey and you may feel a bit rubbish for 10 days or so, but then it will get better.  Other people say itís better to bring it down gradually.  I think thatís up to you, but the only real way to get over it seems to be, to stop it so that your brain can recover.


Subscribe Free

Related Content


Make a comment

Hi Ari

I need to look into this, not least from personal interest!

I'll poke about and see what I can find; meanwhile, maybe someone else can make some suggestions...

Chris chris, Thu, 2nd Aug 2012

I don't know about any meds.  But, it is easy enough to "reset" by stopping drinking coffee, or going to decaf.

Keep in mind that "decaf coffee" is not truly caffeine free.  Usually when I am not drinking coffee, I also avoid other caffeine sources such as caffeinated soft drinks or black tea.

I've quit, and resumed drinking coffee on numerous occasions.  Right now it has been over a month since my last drink of decaf, and perhaps a year or so since having "regular".

On the occasions that I've "quit", I've noticed that the first couple of days I feel extremely drowsy.  However, after a few days, I actually have a rebound period where my alertness may be better than it was with the coffee.  Then, over time, the alertness settles down.

When I've quit coffee in my 20's, I used to get headaches, but haven't noticed them more recently.

After having quit, drinking coffee, taking a Thermos of coffee for a "road trip" can increase one's alertness considerably.

Last year I did some experiments with coffee substitutes.

Dandelion (Catsear) coffee was extremely bitter. 
Pea Coffee was a bit sweeter. 
I found a 50/50 mix between dandelion and pea coffee made a reasonably tolerable mix. CliffordK, Thu, 2nd Aug 2012

The easiest way to reset your caffeine tolerance is just to taper down the amount of caffeine you drink over a week or two. If you do it slowly enough you won't notice any bad effects.

I doubt that there's any non toxic chemical you could take to do this; AFAIK the brain responds to the caffeine by changing the number of neuroreceptors.

The only thing I could think of is if you could find another stimulant that has similar effects but doesn't build tolerance, and then you could switch over to that until your caffeine tolerance subsided. But if that type of chemical even exists I would guess it's probably a class-A drug! wolfekeeper, Thu, 2nd Aug 2012

Not everything is a Class A drug.

Perhaps Theobromine from chocolate.

There seem to be notes of variants of caffeine, Mateine & Theine, but other literature seems to indicate that these are in fact caffeine. 

Anyway, you could get a mild stimulant effect from drinking hot chocolate, or other sources of chocolate, without the caffeine.  There is a theoretical risk of Theobromine toxicity from consuming large amounts of chocolate.

I don't know if there are any studies whether substituting theobromine from chocolate for caffeine from coffee would in fact reduce the dependency on caffeine.  Since the molecules are virtually identical, my guess is that the activity would be similar between the two, and there would be no significant benefit of the change. CliffordK, Thu, 2nd Aug 2012

Not everything is a Class A drug.

Sure, but if it was an unregulated stimulant like that, chances are it would be extremely habit forming. wolfekeeper, Thu, 2nd Aug 2012

DM-235, although a research compound NOT currently labeled for human consumption, has shown to reset caffeine tolerance after single administrations. Researcher, Fri, 28th Feb 2014

I used to take 3 cups min straight for more than a year. Then I stopped abruptly one day. I had fever, severe migraine, pain around the eyes, muscle cramps that I felt even when I was half awake. When I got better I didn't regain the nerve to take a sip until after another week (almost a month no caffeine in total). Now I drink coffee only 3x a week. The rush is back but honestly it wasn't like the very first time. PHIL SORIA, Mon, 3rd Oct 2016

See the whole discussion | Make a comment

Not working please enable javascript
Powered by UKfast
Genetics Society