Does Caffeine and Sleep work?

The current Migaku evidence database contains 2 reusable source documents for Caffeine and Sleep. This answer focuses on strength of evidence and what the studies can or cannot prove. - Results Compared with the placebo, the combined caffeine + paraxanthine condition was associated with faster 2000-m performance and higher mean power output ( p = 0.044; Cohen's d = 0.30). [Bingol Diedhiou A (2026); evidence level 2] - Caffeine alone and paraxanthine alone did not show clear evidence of performance improvement in this sample, although estimates favored both conditions versus placebo. [Bingol Diedhiou A (2026); evidence level 2] - Conditions containing caffeine were associated with poorer subjective sleep quality, whereas paraxanthine alone showed more favorable sleep-related outcomes. [Bingol Diedhiou A (2026); evidence level 2] - Background Although caffeine is widely used in athletes due to its ergogenic effects, the effects of its main metabolite, paraxanthine, on performance and sleep have not been adequately investigated. [Bingol Diedhiou A (2026); evidence level 2] - 8 9 10 11 Long-term observational studies have repeatedly suggested that habitual coffee and caffeine consumption is associated with a lower risk of clinically diagnosed depression, particularly among women [,]. [Turkowska Iwona (2026); evidence level 3] Evidence levels are sorting aids, not final clinical grades. Level 1 usually indicates systematic-review style evidence, level 2 indicates randomized trials or public-health guidance, and lower levels need more cautious wording. This page is educational. People with medical conditions, pregnancy, medication use, or unusual symptoms should ask a qualified clinician before changing supplements, medication, or treatment routines.