I've been reading some studies saying that glycine (a supplement that created some buzz a few years ago due to its apparent sleep-enhancing abilities) at high enough doses in humans is toxic partly due to the fact that glycine metabolism produces ammonia, which we all know certainly *is* neurotoxic.
Then again, these studies mostly (and in humans, virtually exclusively) involved the irrigation fluid used in TURP (Transurethral Resection of the Prostate), which contains glycine. So the actual exposure was probably much greater than what would occur with oral dosing.
There are also other studies plainly demonstrating direct neurotoxicity, but these are, of course, intraperitoneal-injection rat studies, so they are of extremely dubious value, if not completely useless.
Can I get some input on this? I'm sure it's just a matter of exposure as far as when symptoms start showing up, but if there is some underlying "mild" toxicity from glycine, is it worth taking?
I'd love some more input/discussion on this.
Human studies:
http://onlinelibrary...4046.x/abstract
http://www.indianjur...;aulast=Moorthy
https://www.karger.c...FullText/354933
http://onlinelibrary...006.06208.x/pdf
http://onlinelibrary...4411.x/abstract
Rat Studies:
http://www.sciencedi...014488697964633
http://www.ncbi.nlm....pubmed/15490133
http://www.researchg...lycine_is_toxic