I used to take it, and other aminos, years ago. I liked it... but during the past two years most supplements, even multivitamins, seem to aggravate my condition. L-phenylalanine (or however you spell it) and L-Tyrosine were others that seemed to help with the head. I was always cautious about taking too much for too long of a time, etc.--protein balance.
As a matter of fact, before I had this Graves' thing, Niacin--B3--used to be a REAL help to me. Some articles worn about taking large doses, but years ago I used to take 2,000-3,000 mg a day. A lot of times I only took 500-1,000, though. I could swear it helped me so much, but lately it too seems to aggravate my thyroid somehow.
L-glutamine is used by athletes to build up their muscles and lose weight! why are you taking it?