It's the amino acid thatis derived from.
It is known to take the edge off stims (thats why you see it in products such as ) The real version of Tryptophan is alot better.
I have used it for sleep, picture your entire family passed out in fron of the TV after Thanksgiving dinner (Turkey has high amounts of Tryp)
It was illegal because there was a bad batch way back in the 80's that was making people sick. The quality control of the manufacturer was horible, so they banned it