Glutamine is crap and not worth the money.
However, I don't think that it is destroyed by the gut, why would glutamine be destroyed and other Amino's don't???
Regarding Creatine, I cannot deny the effects of it. I cycle it and use and abuse it and it always works, I've done test on my body, with cycling, water consumption, dosage, it works for me.
Peace,
Nat Mike