The 400% increase you are talking about is based on a relatively flawed study conducted a few years back. It is easily disproved because the rise in GH levels could have been attributed to numerous other factors. However, glutamine does increase GH through the stimulation of the anterior pituitary gland.
Increasing any amino acid intake can increase IGF-1's, which are the post cursor of GH.
The reason for this, is IGF-1's are the shuttling agent for amino acids into the muscle fibers. Once they're used they're discarded.
This has been one of the only ways to truly test for GH levels, is to take the increase in IGF-1's in the blood stream.
The study that Rush94 talks about, they conducted the tests using subjects IGF-1 blood content.
Again, this is true in any individual that supplements with any amino acid. It also isn't a real indication that GH levels have increased at all, but rather than IGF-1's were released to compensate for the higher levels of Amino's.
So really, would YOU see an increase of 400% of GH?? No. Would you see an increase of secretion of IGF-1's?? Yes. To what rate?? That depends on what your current levels are right now.
As a 17 year old, your levels of GH & IGF-1's are already sky high. So you probably wouldn't see any increase at all to either of these.
So garlik, is it a waste for me to be supplementing with Glutamine? Because on the same website it says that cooked foods have little to no glutamine in them from the cooking process, and that taking glutamine is necessary for a heavy lifter due to the strain on your muscles and not being able to obtain glutamine naturally.
If you are wanting to use Glutamine for the sole purpose of raising GH levels, then yes, it would be a waste. But taking glutamine is not a waste because it has several benefits such as: increasing protein sythesis, decreasing muscle breakdown, have faster recovery times, etc.. Chances are, you aren't getting enough glutamine through your regular diet if you lift hard. So I do recommend supplementing Gluta-lyn.