Does Caffeine Timing actually make a difference, or is it overhyped?

A randomized crossover trial directly tested caffeine dose and timing before bed and found it prolonged sleep latency and reduced total sleep time in a dose- and timing-dependent way, and this is reinforced by a systematic review of caffeine and sleep across epidemiological and randomized studies reaching similar conclusions. Weighing the data: Caffeine Timing looks an early-stage, lower-priority area for now — the evidence is only moderate (47/100), and its estimated impact (36/100) is on the lower end too.