Treatment with selegiline does not usually cause people to lose weight. Selegiline is a class of dibrachial peptidase IV (DPP-4) inhibitors that can be used to improve glycemic control in patients with type 2 diabetes mellitus and to lower fasting and postprandial blood glucose. However, adverse reactions such as headache, nasopharyngitis, upper respiratory tract infections, and hypoglycemia may occur after taking the drug, and it does not usually cause people to lose weight. Wasting in diabetic patients taking selegiline may be caused by poor glycemic control leading to weight loss, as well as insufficient intake and increased consumption. Patients who lose weight after taking selegiline are advised to go to the hospital and ask the doctor to make a judgment after ruling out non-pathological factors.