The latest entry on Coach Rut's blog mentions ZMA. I've seen it come up in a few T-Nation articles as well, and of course I've seen it on sale at Sports Authority. So after I saw the mention on Coach Rut's blog I went ahead and started to read up on it.
I did some web searching on it, and I have to say what I found wasn't very confidence-building. Essentially, ZMA was developed by Victor Conte at BALCO. I've found all of two studies about its effects, and one was an 8-week study partly funded by a company in which Victor Conte had a financial stake. The other said ZMA, essentially, didn't have a positive effect.
Here's what I found:
(basically just ad copy)
http://www.sportsnutritionsociety.org/s ... -20-04.pdf
(Haven't found the original study from 1998 yet)
So...I'm leaning towards "If I'm eating properly I'm probably not going to benefit." Does anyone have any other information I can check out?