★★★★★
I've been pretty impressed by the results of L Glutamine. When I am feeling out of sorts.. Dark eye circles, concentration problems, anxious, I have found a good tablespoon of this (powder) in a glass of water can really help normalize my state. I am not exactly sure how it is working in my system but I suspect it has to do with my intestinal health and immunity. The Leaky Gut theory seems to be gaining credibility and this may be a remedy for it.. I am a firm believer in taking a break from supplement or only taking them when you feel a need and this is one I like to have around. There is much more detailed info here which you should read 1st before considering...
http://altmedicine.about.com/od/herbsupplementguide/a/L-Glutamine.htm
http://www.thewayup.com/newsletters/041501.htm
EC. you may want to add this to the supplement section.