MSTN and obesity due to melanocortin 4 receptor deficiency: Recently the bimagrumab trial in patients with obesity and type 2 diabetes mellites has demonstrated that not only testosterone, anabolic, androgenic steroids, and/or β-adrenergic agonists have anti-obesity and anti-diabetic effects but that the myostatin pathway can also be effectively targeted in humans to lose fat and to improve glucose homeostasis [23].