Melatonin 3-5 mgs has worked for me as far as reaching REM, but a more put together capsule IMO is ZMA. It's made of zinc monomethionine and aspartate 30 mgs, magnesium aspartate 450 mgs, and vitamin B6 10.5 mgs. Magnesium plays a big role in metabolism. You can grab it for no more than 20 USD at any supplement store. I swear by it. Great deep sleep and recovery... plus it offers additional vitamins and minerals that melatonin do not to aid in muscle repair. Sleep is often overlooked, but vital to muscle growth and recovery...especially when using higher doses of gear. Just my two cents.

Cheers!