I'm glad Werebear mentioned niacin. I take a good bit of it myself, and it makes a difference. I take it with a B-50 and vitamin C (after reading some of Dr. Andrew Saul's work).

I do take GABA on occasion too, but niacin is daily and if I forget for a week or so, there's a huge difference in stress and sleep. When I resume, I'm back to normal in a couple days. It's like magic for me.