My knowledge of L-Glutamine is minimal and goes back many years and is probably out of date by now.......for what it is worth.....
It is an amino acid that is produced naturally by the body and is necessary for protein buildup, particularly after trauma..e.g burns.
It's role in sports medicine has not been scientifically established....effective or non effective.
Excess intake of this amino acid may well cause significant side effects.....rare, but they do exist, particularly in certain neuro psychiatric disorders...depression and certain neurological side effects.
That,s yer lot
LazyGun will fill in the details.