For regulating the sleep cycle and improving sleep disorders, doses of melatonin between 300 micrograms (μg) and 5 mg have been shown to work.^[1][2] Start with 300 μg, and work up to 5 mg as needed. The benefits of melatonin are not dose-dependent — taking more will not help you fall asleep faster. That said, the most effective dose is an area of ongoing research.

To help with sleep, take roughly 30 minutes before going to bed, although some people may benefit from taking melatonin as much as 3 hours earlier.