Research

Hormonal

Caffeine consumption reduces total sleep time by an average of 45 minutes and decreases sleep efficiency by 7%, with the magnitude of sleep loss increasing as the dose increases and the time of consumption approaches bedtime.

To protect your sleep, treat caffeine like a timed medication. If you drink a standard cup of coffee (approx. 107mg), stop consuming it at least 8.8 hours before you plan to sleep. If you consume a high-dose pre-workout supplement (approx. 217.5mg), you must stop at least 13.2 hours before bedtime. Consuming caffeine closer to bedtime will significantly reduce your total sleep time and efficiency, regardless of your habitual intake.

WeakSupportsHIGH confidence
Caffeine consumption reduced total sleep time by 45 min and sleep efficiency by 7%, with an increase in sleep onset latency of 9 min and wake after sleep onset of 12 min.
Carissa Gardiner et al. · Sleep Medicine Reviews · 2023

Why this rating

Systematic review and meta-analysis of 24 controlled studies with robust statistical pooling.

Source

The effect of caffeine on subsequent sleep: A systematic review and meta-analysis

Carissa Gardiner et al. · Sleep Medicine Reviews · 2023

DOI 10.1016/j.smrv.2023.101764

Meta-analysis · 24 studiesCited 273×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →