Fast Twitch

I'm not one to endorse supplements, but I was sent a couple free packets of Fast Twitch to sample. I've been looking for a pre-workout boost, cause work has been crushing me lately.
The only "supplements" I'm taking are Green Bulge creatine and protein. GB has been ok to me.
Well, I'm VERY sensitive to stimulants (I used to have to split 25mg ephedrine caps to half or less). I took half a pack of FT and it kicked me in the ass! Best pump in a long time and great energy. The second half of the pack next workout was the same thing.
Worth a try.