All I've heard is that it's dangerous

sorry if I'm ruining this for you, but I just thought I should let you know that's what I've heard. I could be wrong, so keep researching and listen to the guys who really know what they're talking about, but that's what I've heard.
http://tweakfit.com/eca-stack-safeThat's one of the reviews I've read that have given bad results.
However, I'll restate, I could be wrong. This review could be BS, but I'd be careful and do your research first.