The short answer
If you regularly drink 200 mg or more of caffeine a day (roughly two cups of drip coffee) and suddenly stop, you’ll likely feel withdrawal symptoms within 12–24 hours. The most common symptom is a throbbing headache, followed by fatigue, irritability, difficulty concentrating, and sometimes flu-like muscle aches.
Symptoms peak on day 1 or 2, then gradually fade over 2–9 days. The DSM-5 recognizes caffeine withdrawal as a clinical diagnosis, and the FDA notes it’s one of the most common substance-withdrawal syndromes in the general population.
Common symptoms and how they feel
Not everyone gets every symptom, but the list is consistent across clinical studies:
• Headache — the hallmark symptom. Caffeine narrows blood vessels in the brain; without it, vessels dilate and cause a pulsing headache, often behind the eyes.
• Fatigue and drowsiness — caffeine blocks adenosine, a neurotransmitter that makes you sleepy. When you stop, adenosine floods receptors and energy crashes.
• Irritability and low mood — caffeine boosts dopamine signaling. Withdrawal temporarily lowers it.
• Difficulty concentrating — reaction time and cognitive performance dip measurably in the first 48 hours.
• Muscle aches and nausea — reported in about 10–15 % of cases, usually mild.
Severity scales with your daily intake. Someone drinking 600 mg/day will have a harder withdrawal than someone at 200 mg. Use the Caffeine Calculator to estimate your baseline.
The withdrawal timeline
• 0–12 hours: no symptoms yet. Caffeine’s half-life is about 5–6 hours, so blood levels are still declining.
• 12–24 hours: headache begins, energy drops. This is when most people notice something is wrong.
• 24–48 hours (day 1–2): peak severity. Headache is strongest, concentration is worst, irritability is high.
• 3–5 days: symptoms start to ease. Headaches become intermittent, energy slowly returns.
• 6–9 days: most symptoms are gone. Adenosine receptors have largely recalibrated.
Some heavy users report residual fatigue for up to two weeks, but the acute phase rarely exceeds 9 days. The Caffeine Half-Life Calculator can model exactly how fast caffeine clears your system after your last dose.
How to taper instead of quitting cold turkey
Tapering is the easiest way to avoid the worst symptoms. Cut your intake by about 25 % every 3–4 days:
• Week 1: if you drink 400 mg/day (four cups), drop to 300 mg (three cups).
• Week 2: drop to 200 mg (two cups).
• Week 3: drop to 100 mg (one cup or switch to green tea at ~30–50 mg).
• Week 4: step down to half a cup or decaf (≈2–7 mg per cup) and then stop.
Drink plenty of water, keep sleep consistent, and consider a 15-minute walk when fatigue hits — light exercise raises alertness without caffeine. If headaches persist during a taper, slow the reduction to 15 % per step.
When to see a doctor
Caffeine withdrawal is uncomfortable but not dangerous for most healthy adults. See a doctor if:
• Symptoms last longer than two weeks.
• You experience severe vomiting or can’t keep fluids down.
• You have a history of migraines and withdrawal triggers a prolonged episode.
For context on safe daily limits, see how much caffeine is too much.