I took Glutamine for a few months last year as part of addressing a wide range of GI track issues. I see a fantastic natural doctor, who has helped me resolve numerous challenging problems with my gut. As I understood it, the Glutamine was to aid in repairing or improving the mucus membrane of my intestines. I have no hard facts to back up that claim, however, this doctor has done some amazing things for me, so if she says that is what Glutamine did for me, I believe her. She only had me on it for about 3 months, and had me stop after certain improvements were acheived (mostly a decrease in pain and cramping). I was (and still am) on a few other supplements, which could have also played a role, but with experienced guidance I would say there is some definite benefit to the using Glutamine in the right way for the right purpose.