It was initially developed as a cure for cardiovascular disease but was abandoned due to a study that linked it to cancer. It is not understood that the particular study was flawed in the sense that it was based on feeding a very dosage to rats for a very long period of 104 weeks without any breaks in between.
Even though it was abandoned long ago, bodybuilders have been using it for increasing fat burning and to ensure better cardiac health. Not just this, it is also used by bodybuilders and athletes to improve their endurance levels. I must mention here that Gw 50156 is banned by most sports authorities around the world.