I have taken it, occasionally, for sleep problems - but don't take it regularly. My understanding is that it acts almost like a hormone, so taking it long-term can cause problems for your body (possibly reducing your body's ability to create it, I think?)
But, I've always had a lot of trouble falling asleep. I just don't feel tired at night. And then, I'm *exhausted* in the morning.
Here's what helped. I bet that if you tried this for one week... it would be long enough to either see results, or determine that it won't be useful for you. But, you've got to do all of it - some of it's not effective alone.
And, yes, I realize it sounds nuts

. But, it really does make an enormous difference for me, when I can stick with it.
1. Avoid foods that disrupt sleep. This means alcohol, chocolate, and anything with caffeine. I don't normally drink coffee or alcohol, but the chocolate is a doozy for me. The theobromine seems to effect me over a good, long period... and really noticeably affects my sleep, even if I eat the chocolate early in the day. Too close to bed time, and I'm wired. But earlier in the day, I just feel restless and don't seem to get into "deep, restful sleep". Sad, but true for me!
2. When you sleep, make your room as dark as possible. Seriously, do everything you can to eliminate any stray photons. I cover my alarm clock (so no light comes off of it), taped over any little lights on electronic devices (i.e. my cable box has an "always on" light - I put electric tape over that), etc. And, get good blackout curtains, or do what you need to to ensure there's no light coming from the window. Light signals your brain to be awake, so get rid of it all.
3. No blue light for ~2 hours before bed (give or take). White light has blue light as a component. Studies have shown that light in the blue wavelength (i.e. sunlight!) suppresses our bodies from making melatonin. That means no regular "white" electric lights, and no *screens* - no TV, no cell phone, no tablets, etc.
What I do... you'll obviously want to be able to see and function before bed. You need light bulbs that are on the opposite end of the spectrum from blue... so that means red, yellow, or orange. I use orange - I found one at my local hardware store for ~$5. Set up your bedroom with your orange (or red/yellow) lamp) - then ~2 hours before bed, go into your room, turn on your orange/red/yellow lamp, and turn off all normal lights.
You can stretch, exercise, read books, listen to music, etc. Just avoid blue lights/screens!
* Note: I don't know if you really need the full 2 hours. I'd recommend starting with that, so that you're sure you've given yourself enough time to see if it works. If it works, and once you're well rested, you can play around with the time and see if less works.
** Also note: You can buy plastic safety goggles on Amazon that are orange, and that specifically (OSHA certified!) block blue light. They're cheap too, like $8 or so. I use these if I *must* watch TV or do something online (or for traveling). They work well, but again, I'd hold off on using them until you see if this all works for you. You should do things at 100% first to make sure it works, then play around with where you can compromise and still get good results!
Also, I love my orange light. I believe that the few hours in orange light (and avoiding screens/blue light!) is when you're actually making melatonin. BUT - it absolutely does not work at all for me if I eat chocolate! The chocolate is strong enough to overpower the lovely sleep-inducing powers of non-blue light. Just a warning
- Lastly, obviously, make sure you're comfortable and have a good bed that properly supports you, while giving you enough softness to sink in where you need it. I keep my room really cool when I sleep, I think that helps. I've read of people (i.e. Tim Ferriss) also having good luck with cooling down a few hours before bed using cold baths... but I do fine without those!
When I do these things... mostly avoid chocolate and avoid blue light a few hours before bed, my sleep is *magical*. I get tired in the evening like a normal person, I fall asleep quickly, I go into a deep, restful sleep, I don't toss and turn all night, and I wake up actually feeling rested (a first for me!).
Unfortunately, the "avoiding chocolate" part is really hard for me... but you should definitely give it a try for a week, and see if it doesn't work well for you too.
Good luck, and I really do hope this helps!