I have taken it several times over a few years and these are my experiences. I took the sustained-release version which seemed more natural. I have never had much trouble falling asleep, but wake up frequently, although I do tend to fall back easily. Melatonin does not seem to help this at all. When I take it I fall asleep more deeply (which is good), but when I wake up later, I have a lot of trouble falling back asleep (negates the good part!) I also had the experience once or twice of getting a very agitated feeling not long after I took it. On the whole, it has effects for me, just not worthwhile ones.
I have had pretty good results with pzizz on my iPod, although not as impressive as my husband has. He has trouble falling asleep, but once he's out, he's dead to the world.
note: Benedryl works great on me, at really low doses, and doesn't leave me feeling drugged in the morning, but now I'm reluctant to take it after the whole dementia connection thing. So I guess I'm stuck with pzizz. I hope you can find something that works. For me, a good night's sleep is practically non-negotiable.
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The plural of "anecdote" is not "data".