ZMA vs GABA

ok, i've heard lots of stuff about these 2..
some say ZMA is a natural anabolic (similar to trib in other words)
some say GABA raises GH secretion..

just wanna know are these true?? any studies?
plus if i could only choose ONE, which should i choose?
(oh, please state if you've tried it before as well :) would help my evaluation)

Both are true but they wont have any dramatic results.

You wont notice anything from gaba but the effects will be beneficial.

ZMA will raise test levels slightly but not to the point of sustaning any real anabolic environment.

in other words.. not worth the money?