Is its apparantly mimics a certain illegal drug (banned recently) named Adderal. Adderal was a concentration drug, commonly used to help focus on things.
A couple of people have related it's effects to Adderal, helping in the gym with focus and concentration towards muscle groups. It's a nootropic, a supplement that is like a booster for the brain. I think it had a bit of caffeine, or a different stim for the muscles, but it wasn't really enough to really make it a huge, huge difference.
I tried it a few times after obtaining a few samples from a GNC, and my results weren't really clear.... I took it without food before lifting, and I'm not sure if it really worked.