Melatonin can help initiate sleep but does not help maintain sleep and is generally not recommended except for jet lag treatment.

“I have talked before on this podcast about melatonin, why I am not a fan of using melatonin in order to enhance sleep. It can help one get to sleep, but not stay asleep. Dr. Matt Walker sleep expert from University of California, Berkeley. I think I don't want to put words in his mouth, but in our discussion about melatonin on this podcast when Matt was a guest in his book and on other podcasts, Matt has generally stated that the use of melatonin except for treatment of jet lag is generally not a good idea. And I agree.”