The science-backed caffeine sweet spot for a 180-pound lifter is 250 to 500mg, but if you train after 3pm and go to bed at 11, the math literally does not close. That same dose sharpening your focus and strength output is still halving itself every 5 hours, wrecking your sleep architecture even 6 hours later according to a clinical sleep study. The honest answer is that the performance benefits are real, the timing constraint is real, and nobody in the research has fully resolved the tension between them.