Caffeine Timing Discipline
Cut caffeine 8 hours before sleep. Protects sleep architecture even when subjective sleep feels fine.
What it does
Caffeine's half-life is long enough that an afternoon coffee is still active at bedtime. Subjective sleep onset can stay normal while deep sleep degrades. The fix is mechanical: nothing caffeinated after early afternoon.
Caffeine antagonizes adenosine receptors, blocking the buildup of sleep pressure. Its 5-to-7-hour half-life means meaningful concentrations persist long after the perceived stimulant effect fades.
What the evidence shows
Overall evidence strength: Moderate certainty
Who it's for, who should skip
Anyone whose sleep quality is degraded by afternoon caffeine — especially slow CYP1A2 metabolizers. The earlier the cutoff, the cleaner the benefit.
Stacking & alternatives
Access & cost
Self-directed — no purchase required.
Last reviewed 27 August 2026.