My understanding is that melatonin helps you fall asleep, but doesn't help you stay asleep.

In general, I have no trouble falling asleep, but I typically wake up once or twice at night and am usually unable to sleep more than 5.5 hours. I've tried 3mg Melatonin tablets in Ecuador, and I've tried a couple of different brands of 10mg time-release Melatonin gummies from the US. None of them had any noticeable effect on me.

The only thing that has worked so far, is physical activity. We just moved to Europe, and the first two weeks was a lot of buying and building furniture, slept great those two weeks. Now that I'm back to my normal office worker life, my sleep has also gone back to not being great.

(I track my sleep using the AutoSleep app on iOS, wearing an Apple Watch at night)