how long before sleep to take melatonin
1 When to take: Depending on the severity of the sleep problem, take time-released melatonin 1 to 3 hours prior to the time you usually fall asleep. 2  Since time release melatonin only lasts for 3 â 4 hours, any need to shift sleep schedules more than 3 hours may require taking another pill in 3 or 4 hours.