I use the stacker 3's without ephedra at home, and stacker 2's with ephedra while at work. I have built so much muscle with them!! I was getting weak on the Atkins diet alone, and a body building pal suggested the one's with ephedra to help in building muscle mass. It has really worked!! I have lost lots of flabby skin and fat, and kept and gained muscle. You are not suppose to use the ephedra if you have high blood pressure, or any heart problems so be very careful and get a physical if you decide to use them.