I use 10mg melatonin daily. I think you can get time-release melatonin - I wonder if this might help?
Also as mentioned, investigate zinc and magnesium (I prefer these as citrate, in capsules rather than tablets); you can try an Epsom bath (several cups of salt will be required) to get some magnesium transdermally; very relaxing at bedtime.
Another thing I'll mention is that light bleaches out melatonin - endogenous or supplemental - so when you take it, let it take you by staying in a very dark room while it kicks in. Even a night-light can be too much. You need DARK, so turn off all the lights and listen to music if you like, but no reading or tv. You might find it kicks in a little faster if you tuck it between your gum and your cheek, or if you chew it up and keep it in your mouth for a few minutes before you swallow it. You can also try keeping one beside the bed so when you wake up, you can chew it and let it take you back to sleep.
Plus there's always the trusty late-night orgasm.
I rub on my progesterone cream at bedtime; this tends to help promote sleep but I can appreciate a man not wanting as much progesterone as a woman. Men DO need some progesterone though - look up "contrarian endocrinology" and you'll see a google hit called something like "progesterone for men".
