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My Experience with Caffeine Withdrawal: the Science Behind the Headaches

Co-written with Gene Food staff.

Caffeine gives me the jitters, which makes sense in light of my genetics. I am homozygous for the CYP1A2 gene, which means I metabolize caffeine more slowly than some of my buddies who drink espresso rather than warm milk before heading off to bed.

When I was first reviewing my genetic charts, this information made perfect sense to me as I’ve always felt caffeine affected me to a greater extent than many of my friends. If I were to drink a latte before bed, I’d be up half the night tossing and turning, so I usually choose green tea over coffee.

However, despite knowing that large doses of caffeine don’t work well for me, I will occasionally still go on a run of morning espressos for a few days straight. When I come to my senses and quit the coffee, inevitably a withdrawal period begins, usually with a headache for a couple days and a feeling of sluggishness.

Caffeine may be the world’s most popular drug, but it’s still a drug and experiencing withdrawal is a great reminder of this fact.

Progression of caffeine addiction

The first time in recent memory I went on a sustained coffee blitz, I was hanging out in sleepy San Diego, which if you haven’t been, is a city characterized by the country’s best weather, and a corresponding dearth of work vibes.

Caffeine seemed in some strange way necessary to prevent joining with the collective slumber. I was on Austin time, so I’d wake up at 5:30 every morning and walk my dog, Ned.

On these walks, we’d stroll past an open air coffee concept called Lofty Coffee, in San Diego’s Little Italy neighborhood. Here’s this completely outdoor coffee shop, with great branding and a fine selection of different caffeinated drinks to warm you as the marine layer rolled out. The people “inside” looked so happy and content sipping on their various black water beverages. I couldn’t resist. It was time for me to join the ranks of the coffee tribe.

Caffeine addiction and developing a tolerance

For about 10 days in a row, I ordered a Turkish Latte, which is offered at Lofty with house made coconut milk, and cardamom. On day one, I had a rush of euphoria that lasted an entire day. I felt like I could take on the world. My brain went into high gear. Mood was improved, productivity was up, smiles were in plentiful supply. Optimism flowed. And that ride lasted through about day four. But on day five, I noticed that the buzz wasn’t quite as good as it had been on previous days. When I finished my latte, I immediately wanted another, but to keep things in check, I would order a decaf Americano as a follow up. Later in the day I would have multiple cups of green tea.

In other words, the returns diminished as I drank more caffeine.

I was developing a tolerance.

By day 6 or 7, a latte on an empty stomach gave me a little bit of what could best be described as sour stomach. By day 9, I seriously considered ordering a double, but never did.

You get the point.

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Caffeine withdrawal – breaking the addiction

A couple mornings during my run I’d wake up, and think, “you know what, I will skip the coffee this morning, I don’t need it.” But inevitably, I’d show up at the coffee shop for my latte nonetheless, rationalizing the trip the whole way.

Hey, coffee does lengthen telomeres, right?

Then, one day I stopped cold turkey. No latte, no decaf Americano, no multiple cups of green tea in the afternoon. What happened next came as a surprise.

I developed full on caffeine withdrawal. I felt like an addict drying out at a rehab center.

My caffeine withdrawal symptoms

The day I opted out was a day marked by these symptoms:

  • a terrible headache,
  • stomach upset,
  • and some lightheadedness.
  • I was irritable and cranky.
  • I legitimately felt like I was sick, except I knew I wasn’t.

I stayed in bed a good chunk of the day and got very little done.

As I clicked off more caffeine free days on the calendar, I returned to normal, but the experience of having a true withdrawal from an actual drug was a first for me and it was eye opening. It got me wondering, did my CYP1A2 genotype have something to do with the severity of my withdrawal?

I’d read that coffee constricts blood vessels in the brain, and that when you quit, the passageways open back up, which causes a headache. But I wanted to real scoop on what causes withdrawal, so I asked, you guessed it, Aaron, the badass scientist on our team. Here’s what he had to say.

The science of caffeine withdrawal

Thanks John. There’s actually a really nice study which looks at just this effect. Published by researchers from the University of Vermont and Johns Hopkins University School of Medicine, which you can read here if you’re interested in understanding everything. While the study was small, only 16 subjects, it was double-blinded (neither the subjects nor the researchers know which treatment a person is on) which is the gold standard.

The regular caffeine users switched between a maintenance dose of 400 mg of caffeine or a placebo without any caffeine, and at regular points received either high dose caffeine or placebo challenges. The idea behind this switching is to see what effects a chronic and acute withdrawal from caffeine would have on people with differing daily intakes.

To give you an idea of the dosing see this table from Amber’s previous post.

Caffeine comparison

Beverage typeCaffeine per cup (8 oz)
Coffee (brewed)95-165 mg
Energy drink27-164 mg
Black tea (brewed)25-48 mg
Cola 24-46 mg
Green tea (brewed)25-29 mg
Decaf coffee (brewed) 2-5 mg

Throughout the trial EEGs were recorded to demonstrate brain function, and blood flow through two key arteries was assessed as well.

So what did they see?

Well, acute caffeine abstinence lead to increased blood flow through those arteries which the authors suggest ties in with those severe headaches, which correlate with going cold turkey. This acute caffeine abstinence also led to changes in brain function as measured by EEG, associated with increased drowsiness and decreased alertness. Even the answers to questionnaires taken by the subjects show a similar effect, with increased ratings of words like “tired,” “fatigue,” “sluggish,” weary and decreased ratings of “energetic,” “friendly,” “lively” and “vigor.”

All of which fits with John’s description (and my own experiences when I switched back from strong coffee, to tea). And for further bad news the authors of this study, and others, report that daily intake and length of intake will also significantly worsen the effects of going cold turkey.12

Closing thoughts

Well, there you have it, as it turns out, caffeine withdrawal is caused by increased blood flow through key arteries in the brain, which causes pain in the form of headaches, and presumably dizziness for some people as well.

The more caffeine you drink, the worse the withdrawal will be.

If you’ve had an experience with caffeine withdrawal, we’d love to hear from you in the comments.

Dr. Aaron Gardner, BSc, MRes, PhD

Dr. Aaron Gardner, BSc, MRes, PhD is a life-scientist with a strong background in genetics and medical research, and the developing fields of personalized medicine and nutrition. Read his full bio here.

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  1. cvxd says:

    I started drinking black tea about 15 years. One cup noticeably improved my mood and made everything better. I only moved up to 2 cups in the morning but went from the basic supermarket American tea to Irish Breakfast Tea – a well made, strong and delicious tea. I ran out 2 mornings ago and decided to see how I feel without it.

    Well, it has been rough! The headache started at about 24 hours and came and went until I just took Ibuprofen. It felt like a glass bottle was smashed over my forehead with the glass shards imbedded. The first day I was agitated. Thankfully I didn’t have anything to do except go food shopping. That was not nearly as fun as it had been.

    I sleep ok the first night and I woke up to urinate early in the morning which is usual. Then I was kind of psychotic for a few hours! Not really but my thinking was definitely different and again, not fun. I only urinated like twice today. Typically with tea I would go a twice as much, at least.

    Right now I feel decent and feeling really good about giving up tea indefinitely. This stuff is bad! Really bad. However, the world doesn’t think so. If it didn’t make me feel so good I would definitely give it up. I might try it in a few days and see what I feel like. I don’t know. My life was fine without it. We’ll see.

  2. Toni says:

    Wow thanks for your article! My girlfriend gave me an organic coffee 3 days ago. I have been happily drinking it thinking I’m getting my normal coffee high and then mysterious headache develops with a whacking headache on waking and was feeling very depressed as well, nauseas and light headed when I glance at the label on the coffee jar 99.7% caffeine free! So unknowingly weaned myself off coffee but boy a shock to realise my body was demanding the high from caffeine even though I was actually not intentionally weaning myself, I was just trialing the organic taste! ; ) still have a slight headache but I guess I’ll keep abstaining after the wake-up call!

  3. HyT says:

    Hi John,

    Very interesting article! I am Day 2 cold turkey. Main reason being because I started to notice staining in my teeth. I only really started drinking tea 4.5 years ago after the birth of my first, continued through my second. What I’m shocked about us that I wouldn’t consider myself caffeine addicted. I have maybe 3-4 cups of tea throughout the day, soft drinks occasionally.

    I normally have a cup of tea first thing in the morning, so around 730am. I decided to start my abstinence from caffeine yesterday – so last cup of tea around 8pm the day before last. I would say around 18hrs in I started to get a little headache, a little tired and a little grumpy. 24hrs in those symptoms worsened and added nausea. Exhaustion kicked in here and I ended up falling asleep on the sofa at 7pm after the children. 1120pm woken up by the husband to go to actual bed to sleep.

    I lay there for maybe 10 minutes before having to get up and was violently ill a few times. Back to bed and slept all the way until morning. Morning was the worst of it I think. Very bad nausea, headache, light sensitive, vomiting on an empty stomach. I was curled up in a ball in the dark for the next 4 hours before the symptoms started to abate.

    40hrs after my last cup of tea I am feeling much better. The nausea is mostly gone, no light sensitivity, headache is slightly there but only really noticeable when bending to pick things up. I’m guessing this is to do with putting more pressure on those narrowed vessels but I may be wrong in that. I haven’t really tracked anxiety but I wouldn’t be surprised if that was also affected!

    Keep up the good work!

  4. Jeff says:

    Day 2 cold turkey. I have drank around 48 ounces of coffee a day for decades. I am wondering if going cold turkey is a good idea now… These headaches are awful. I never think of coffee as a drug, just something I enjoy. But wow. This is an eye opener. I want to quit drinking coffee because of anxiety and to see if my blood pressure may come down a bit. Thanks for the article.

    • I would suggest for anyone who is thinking of quitting caffeine cold turkey to do a slow process instead. Sometimes our bodies go through more stress quitting something cold turkey then weaning down. Here’s a example that will make your intolerable life without caffeine much more tolerable. The first day without caffeine you wake up and your normal, because your body doesn’t know you’re about to take its livelihood away from it so skip the morning brew and start your daily routine. You were slowly in the middle of the days start to feel the drowsiness and headache creep up on you, that’s when you ran the organic green tea bag that’s going to save your life through this journey. Put that one tea bag in steaming hot water and feel your headache go down slowly. Then go to bed early that night. The next day wake up and you’re gonna feel crappy you’re not gonna be able to think clearly and you’re going to be very sleepy and you might even have a headache go ahead and reach for the one green teabag again. Steep it for three minutes and make sure to drink tons of water throughout this process because when your body is withdrawing from anything it needs water to flush out the toxins. Now later on in the day you just might come across one of the worst headaches you’ve had yet go ahead step one more green tea bag but try to only drink half of this. This will get you through the night without a banging headache and under the next day. Now you’re on a day three where you can go down to one green tea bag. Try to drink it around noon so it will last you. You can repeate this for day four as well but by day five you should be over the horrible with draws an able to make it on your own without any caffeine at all. I know this is a process but from my experience of quitting caffeine a couple times throughout my life because of anxiety this processed saved me. What some people don’t know is with drawls can cause your horrible anxiety is well So I would go into panick attacks trying to quit until I found this great way to ease my body down from the bumpy caffeine ride it was on.

  5. Jason Shields says:

    Hey John! Fantastic article and well-researched! I’m on day 8 of being caffeine free, although I should mention that yesterday I had an espresso coffee just to test my anxiety levels, mood, etc. Sure enough, I had the worst anxiety that last for at least 5 hours straight!

    I’m a psychologist and I was also born with cerebral palsy. Growing up, I have suffered from depression and horrible anxiety attacks. The medication I was put on made me extremely tired and so I would go to coffee and caffeine for a pick-me-up. I also have an addictive nature so I would go overboard to experience a greater clarity and focus of mind. Since I’ve stopped, the first three days were hell but when I got to day 6, everything leveled out. Our brains are highly adaptable and once you get off of the toxin, you do feel better and more outgoing! Thanks again for your article and testimony!


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