What are the side effects of quitting caffeine?

Withdrawal symptoms generally begin 12 to 24 hours after stopping caffeine use but can appear within 6 hours. So it’s not unusual to notice the symptoms in the morning after drinking coffee the previous day. On average, withdrawal symptoms last one or two days, but they can continue for as long as two weeks.

Headache is the most common withdrawal symptom, experienced by up to 50% of caffeine users. Other symptoms are fatigue, low energy, decreased alertness, and depressed or irritable mood. Intellectual performance, vigilance, and psychomotor speed decline.