The sleep hormone melatonin is not actually a sleep aid and will not knock you out after taking it.
But the sleep hormone melatonin does help you know it's time for sleep and helps keep you asleep so you'll need to take both the melatonin and a sleeping pill.
Sometimes I have to take the regular sleeping pill and the melatonin when the sleeping pill starts to wear off or doesn't want to keep me asleep.
The sleeping pill will knock you out and put you to sleep but then the melatonin helps tell your brain that it's time for sleep so you should stay asleep when taking melatonin.
Some people can fall asleep with just taking the melatonin however some people like me need the sleeping pill as well with the melatonin to fall asleep.