Remember the guy at the local GNC chucking me a bottle of this a while back. Per his sales pitch it guarantees you get 8-9+ hours of sleep....or so you think. He was an elite level cyclist/mtn biker (represented the US on several occasions) and said you take it before bed and even if you only get 5-6 hours of sleep like most of it, you get 8-9 hours of rest/recovery during. He also admitted to me that over half the goodies at GNC would likely make you fail a piss test.
For reference I don't shop at GNC but he would frequently visit the adjacent gym I worked at and knew I was trying to train for a marathon and other endurance endeavors at the time. I took it, literally can't say it did anything. Was running in the 60-70 mpw range. Full time job, coaching, etc. Felt the same. Definitely some placebo effect doing on for sure. Blew up in the marathon not due to lack of recovery but running it like and idiot.