Quick answer: Common caffeine withdrawal symptoms are headache, fatigue, drowsiness, low mood, irritability and trouble concentrating. A review of 66 studies found symptoms usually start 12–24 hours after your last caffeine, peak at 20–51 hours and last 2–9 days. Cutting down gradually is the best way to avoid them.
If you drink coffee every day and skip it, the headache and fog that follow are real withdrawal, not imagination. People also use “caffeine crash” for the slump some feel as a dose wears off the same day. Here is what the research says about both, and how to cut back without feeling awful.
In this guide 5 sections
What is a caffeine crash?
Caffeine keeps you alert mainly by blocking adenosine, a brain chemical that promotes sleepiness. As the caffeine level falls, that sleepiness can come back, which many people call a crash. Caffeine’s half-life is usually 3 to 7 hours in adults (see how long coffee stays in your system), so the drop is gradual rather than sudden.
True caffeine withdrawal is different. It happens when regular caffeine use stops or drops sharply, because the brain has adapted to having caffeine. According to the FSANZ caffeine safety assessment, habitual use increases adenosine receptors in the brain; when caffeine stops, adenosine’s effects are stronger, including widening of blood vessels in the brain, which leads to headache. Symptoms last until receptor numbers return to normal.
How long does caffeine withdrawal last?
In the 2004 review by Juliano and Griffiths, symptoms typically began 12–24 hours after stopping, were worst at 20–51 hours, and lasted 2–9 days. Withdrawal was seen after stopping doses as low as 100 mg a day, about one cup of coffee, and higher daily doses generally meant more frequent or stronger symptoms.
What are the symptoms of caffeine withdrawal?
1. Headache
Headache is the classic sign: in experimental studies, about half of people who stopped caffeine got one. Caffeine is also an ingredient in some pain relievers, and FSANZ notes that a pain reliever plus a small amount of caffeine is the most effective treatment for withdrawal headache.
2. Fatigue and drowsiness
Tiredness, low energy, drowsiness and feeling less alert are among the best-supported symptoms. With caffeine no longer blocking adenosine, its sleep-promoting effect is felt more strongly.
3. Irritability and low mood
Irritability, low mood and feeling less content are also validated withdrawal symptoms. Being short-tempered before your first coffee can be partly this, although overnight is usually shorter than the 12–24 hours it typically takes for withdrawal to begin.
4. Difficulty concentrating and brain fog
Trouble concentrating and feeling “foggy” or not clear-headed appear on the validated list. The review also judged flu-like symptoms, nausea or vomiting, and muscle pain or stiffness as likely withdrawal symptoms.
5. Anxiety and jitters
Anxiety is not on the review’s list of validated withdrawal symptoms. Jitters, anxiety, restlessness and a fast heart rate are more often a sign of too much caffeine, according to the FDA. If you feel this way while still drinking coffee, see signs you’re drinking too much coffee.
How do you avoid a caffeine crash or withdrawal?
Cut down gradually
FSANZ notes that withdrawal can be prevented or minimised by reducing caffeine gradually rather than stopping all at once. Mixing in decaf or swapping one cup for a lower-caffeine drink are easy ways to step down.
Don’t rely on coffee to fix poor sleep
Caffeine late in the day can cut into sleep and leave you reaching for more coffee the next morning. A sleep study found that 400 mg taken even 6 hours before bed reduced sleep. Keeping coffee to the morning breaks that cycle.
Keep your daily intake steady
Withdrawal is triggered by a sharp drop. Very different amounts from day to day, such as lots on weekdays and none at weekends, set you up for weekend headaches. If you are worried you rely on coffee too much, see are you addicted to coffee?
Frequently asked questions
How long after quitting coffee do withdrawal symptoms start?
Usually 12 to 24 hours after your last caffeine, with the worst symptoms around one to two days in.
How long does a caffeine withdrawal headache last?
Withdrawal symptoms, including headache, typically last 2 to 9 days, easing as your brain adjusts.
Can one cup of coffee a day cause withdrawal?
Yes. The review found withdrawal symptoms after stopping doses as low as 100 mg a day, roughly one 8 oz cup of brewed coffee.
For the wider health picture, see is coffee good for you? If symptoms are severe or don’t improve, talk to a doctor.
This article is for general information and isn’t medical advice.