Caffeine Withdrawal: Symptoms, Timeline and How to Cut Down Without the Headache

Caffeine withdrawal usually starts 12 to 24 hours after your last coffee, is at its worst between about 20 and 51 hours, and fades over two to nine days. The signature symptom is a dull, persistent headache, often with tiredness, low mood and trouble concentrating. It can follow a habit as small as one cup a day — and it can be avoided almost entirely by cutting down in steps instead of stopping at once.

Those numbers come from the most thorough review of the subject, in which Laura Juliano and Roland Griffiths analysed 57 experimental and 9 survey studies.

What it feels like

Of 49 symptoms that had been attributed to caffeine withdrawal, Juliano and Griffiths found ten that stood up to scrutiny:

• Headache
• Fatigue, decreased energy and decreased alertness
• Drowsiness
• Low mood — decreased contentedness and depressed mood
• Difficulty concentrating, and feeling foggy or not clear-headed
• Irritability

They judged three more — flu-like symptoms, nausea or vomiting, and muscle pain or stiffness — likely to be real as well.

Headache is the most common. In the experimental studies, about half of participants developed one. Withdrawal was bad enough to cause clinically significant distress or difficulty functioning in 13%. That is a minority, but it is not trivial: one person in eight who quits abruptly may find a day or two of work genuinely hard.

The timeline

Put dates on it. If your last coffee is at 8 a.m. on Monday, symptoms would typically start between Monday evening and Tuesday morning. The peak window runs from about 4 a.m. on Tuesday to 11 a.m. on Wednesday. By somewhere between Wednesday and the following Wednesday, it should be over. Tuesday is usually the hard day — worth knowing before you choose which week to quit.

The size of the habit matters. Across the studies, symptoms became more common and more severe as the usual daily dose went up.

How little caffeine it takes

Withdrawal is not reserved for people who drink a pot a day. In a set of four double-blind experiments, Suzette Evans and Roland Griffiths found that:

• Stopping a habit of 100 mg a day — about one cup of filter or instant coffee — produced significant withdrawal. Stopping 300 or 600 mg produced more.
• Withdrawal appeared after only three days of taking 300 mg a day, and was somewhat worse after one or two weeks.
• It made no difference whether 300 mg was taken as one morning dose or spread across the day.

So a single daily cup is enough to build a dependence your body will notice, and it takes days, not months.

Why it happens

Caffeine works by blocking adenosine, a chemical that builds up during the day and makes you feel sleepy — the coffee and sleep guide explains the mechanism. Take caffeine every day and the body adjusts to having it around. Take it away and that adjustment is suddenly unopposed.

One measurable part of this is blood flow. Caffeine narrows the blood vessels in the brain. In a 2009 study, regular users who were switched to a placebo without knowing it showed faster blood flow in two major arteries of the brain within 24 hours, along with more tiredness and less vigour. That rebound in blood flow is thought to be behind the withdrawal headache.

Is it a real disorder?

Yes, formally. The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) lists caffeine withdrawal as a diagnosis. The criteria are prolonged daily caffeine use, then an abrupt stop or reduction followed within 24 hours by three or more of:

1. Headache
2. Marked fatigue or drowsiness
3. Dysphoric or depressed mood, or irritability
4. Difficulty concentrating
5. Flu-like symptoms — nausea, vomiting, or muscle pain or stiffness

The symptoms must cause clinically significant distress or impairment, and must not be better explained by something else, such as migraine or a viral illness.

The uncomfortable part: the morning lift

If you drink coffee every day, some of what it does for you in the morning is simply undoing the withdrawal that built up overnight.

In a 2010 study led by Peter Rogers at the University of Bristol, 379 people — some who rarely had caffeine, some who had it regularly — went 16 hours without it and were then given caffeine or a placebo without knowing which. In the regular consumers, the placebo lowered alertness and brought on headaches. Caffeine brought them back to normal — and no further. It did not make the low consumers more alert either. The authors concluded that with frequent use, "no net benefit for alertness is gained, as caffeine abstinence reduces alertness and consumption merely returns it to baseline."

The 2009 blood-flow study reached a similar verdict: after weeks of daily caffeine, there was almost no evidence of any lasting net effect on its measures.

These are laboratory findings, and coffee clearly does other things people value, from taste to ritual. But the next time the first cup feels like it switches your brain on, it is worth knowing that part of what it switches off is the withdrawal.

When withdrawal catches you out

Withdrawal often turns up without anyone deciding to quit.

Surgery. Patients fast before an operation, which usually means no morning coffee. In a Mayo Clinic survey of 233 outpatients, postoperative headaches occurred in 22% of daily caffeine drinkers but only 7% of non-drinkers. Among the caffeine drinkers, those who had caffeine on the day of surgery had fewer headaches than those who abstained, 17% against 28%. An earlier study found that each extra 100 mg of usual daily caffeine raised the odds of a postoperative headache by about 16%. If you have a procedure coming up, ask your care team about your usual caffeine.

Travel, illness and busy days. Time zones, a stomach bug or simply a morning with no chance of coffee can produce the same headache by Tuesday afternoon. If you recognise the pattern, the cause is easy to test: resuming caffeine relieves withdrawal symptoms, so a small coffee usually settles the question.

How to cut down without the headache

The evidence for tapering comes from the same Evans and Griffiths experiments. People maintained on 300 mg a day were moved, without knowing it, to lower doses. Cutting them to 200 mg produced no measurable withdrawal. Symptoms appeared only when intake fell to 100 mg a day or less.

That suggests the practical rule: cut in steps of about a quarter to a third, wait a few days at each step, and make the last steps the smallest. There has been no large trial of tapering schedules, so treat any specific plan as a sensible default rather than a tested protocol. An early study of gradual reduction, admittedly in only three people, took them from almost nine cups a day to under three, and the reduction held at a ten-month follow-up.

Here is one way to come down from four cups of instant coffee a day — about 400 mg at the NHS estimate of 100 mg a cup:

Things that make it easier:

• Mix decaf into your beans. Blending regular and decaf coffee in shrinking proportions lowers the dose while the cup looks and tastes the same.
• Use tea as a step down. The NHS estimates about 75 mg in a cup of tea against 100 mg in a cup of instant coffee.
• Keep the ritual. Much of a coffee habit is the warm cup at a certain time. Keep it and change what is in it.
• Count all your caffeine. Cola, energy drinks and some painkillers contain it too.
• Pick the week. If symptoms come, they tend to peak a day or two after a step down, so do not schedule a step just before a deadline.

If you are cutting down for a reason

People often cut back for sleep, anxiety or pregnancy. The coffee and sleep guide explains why a later cutoff can matter more than the total; the caffeine and pregnancy guide covers the 200 mg limit and the research behind it. In each case, a taper over two or three weeks costs little and spares you most of the withdrawal.