At least 8 hours before sleep [1]. [1] https://www.sleepfoundation.org/nutrition/caffeine-and-sleep#:~:text=How%20Many%20Hours%20Before%20Bedtime,may%20help%20

At least 8 hours before sleep [1]. [1] https://www.sleepfoundation.org/nutrition/caffeine-and-sleep#:~:text=How%20Many%20Hours%20Before%20Bedtime,may%20help%20minimize%20sleep%20problems https://www.sleepfoundation.org/nutrition/caffeine-and-sleep....