Clenbuterol is a medication that has been used for many years to help people lose weight. It has also been used in the past to help people build muscle. There is some research that supports the idea that clenbuterol can help increase muscle mass. However, there is also research that suggests the opposite may be true. Since the early 1990s, clenbuterol has been popular as a performance-enhancing drug in bodybuilding circles. The drug is supposedly effective at increasing muscle power and strength. However, there is still much unknown about the effects of clenbuterol on the body.