Clenbuterol’s initial use was as an asthma drug. However, bodybuilders, performance athletes, and those wanting to lose weight are now using the drug. Clenbuterol can be used as a weight-loss aid because it can increase a person’s metabolism. As well as reducing body fat and weight, it also allows the user to retain both muscle mass and body strength at the same time. Clenbuterol became known as a celebrity diet secret because of its apparent use by celebrities and famous athletes. One study reviewing data from two regional poison centers in the U.S. found that in 11 of the 13 reported casesTrusted Source of people taking clenbuterol, it had been used for weight loss reasons or as part of a bodybuilding regime.