Sleep
Caffeine Half-Life
Caffeine half-life is how long the body clears half a dose—often five to seven hours. Late caffeine can still disrupt bedtime even if you feel tired.
Caffeine half-life is the time your body needs to clear roughly half a dose—often about five to seven hours on average, longer with pregnancy, some meds, or slower metabolism. Afternoon coffee can still circulate at bedtime, delaying melatonin and deepening sleep pressure debt.
Cut-off experiments—no caffeine after 2 p. m.
or ten hours before bed—reveal personal thresholds better than averages.
Common questions
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How late can you drink coffee for sleep?
Try stopping caffeine eight to ten hours before target bedtime for two weeks. Sensitive sleepers may need noon cutoffs even if friends tolerate evening espresso.
Related terms
Put Caffeine Half-Life into practice
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