10 grams 3 times/day. Usual adult dose for dietary supplement: average dose: 10 g orally up to 3 times per day (total 30mg max) http://www.Drugs.Com/mtm/glutamine.Html as always, any time you are considering a new diet or supplementation, consult with your doctor to personalize dosing to your needs.
Well... Glutamine may provide a roll in repletion of stores of this Amino Acid after strenuous , usually marathon- like events. Depletion usually affects the immune system causing susceptibility to colds. As far as athletes, taking glutamine purportedly helps stressed muscles to recover faster. That's my take.