I'm very impressed with everything you have tried. If you can figure this thing out, you might make some major discoveries. The fact glutamine isn't helping is rather perplexing...you could try larger doses like 30g...or try different brands, making sure they are in the micronized form. Personally I use a veggie source from fermented beets PVL brand. Have you done the yasko genetic methylation panel? I saw they had an RNA for leaky gut...might be worth a try http://www.holisticheal.com/leaky-gut.html There must be some other tissue/intestinal lining repair supplements out there as well.... I know the peptopro is a hyrolyzed casein, but it is quite unlike standard whey/casein proteins. It dissolves clear in water....its that fine, and supposedly is >80% di and tri peptides. Regular casein is very,very different and sits in your stomach and forms a goo for hours, so yea i would not recommend that. I have issues with the regulars as well. I cant find anything more pure than peptopro though. The hydrolyzed collagen has a very skewed amino acid profile. Also I can't quite figure this out....but supposedly its between 2000 - 5000 daltons peptides. A single amino acid averages 110 dalton...so I am assuming a dipeptide would be about 250 daltons and a tri peptide around 400 maybe. Therefore your body still has to work quite a bit to break the hydrolyzed collagen down...where as with the peptopro its mostly negligible going straight into your blood. There are glutamine peptides as well...but those are sourced from wheat/gluten which makes me leery. I wish you well in this journey. Your very adept at figuring things out.