Athletes who use this over-the-counter supplement believe it stimulates production of the hormone testosterone in the body. They also believe it builds muscle mass, repairs injury more rapidly, and enables them to train harder.
Little evidence exists to support claims about its effectiveness or ability to increase muscle mass.
There are also no studies available on androstenedione's safety. Currently researchers are trying to find out what doses raise testosterone levels high enough to have an effect on performance and if these levels can cause harm to the user.