Caffeine Cutoff 8 Hours Before Sleep
No caffeine within 8 hours of sleep. Its 5–6 h half-life means an afternoon coffee still occupies adenosine receptors at bedtime.
Consume no caffeine within 8 hours of your intended sleep time, because its 5–6 hour half-life means an afternoon coffee still occupies adenosine receptors at bedtime. Cutting it cleanly is the highest-yield sleep hack for habitual coffee drinkers.
The protocol
- Rule: no caffeine within 8 h of bedtime.
- Includes: coffee, matcha, energy drinks, pre-workout, dark chocolate (>50g).
What you get
- Better sleep quality.
- More deep sleep.
- More REM sleep.
Contraindications
- No medical contraindications — comfort-only adjustment.
Evidence level
High. Caffeine's effect on sleep latency and architecture is well-supported by multiple studies; an 8-hour cutoff is a conservative, evidence-aligned guideline given its 5–6 hour half-life.
Related protocols
Sources
AgeGen never invents studies and never recommends prescription drugs by brand. Biohacks are experiments, not prescriptions — honour the contraindications and talk to a clinician if a condition above applies to you.