Skeletal Muscle Mass Loss with Use of Dual GLP-1/GIP Receptor Agonist Tirzepatide: CaseReport and Review of Literature

Abstract Obesity is a complex chronic disease which poses a significant impact on health and wellbeing. While lifestyle modifications remain important in the treatment of obesity, incretins, such as glucagon-like peptide-1 receptor agonists and the dual incretin receptor agonist tirzepatide, have revolutionized diabetes and weight management. We report a 69-year old male initially presenting with a BMI of 31.2 kg/m2 and hemoglobin A1c of 5.9%, whose treatment with tirzepatide resulted in a reduction of weight by 28.7 lbs and a decrease in BMI to 26.8 kg/m2. Patient however, also experienced a 9.9 lb loss of skeletal muscle mass. Multiple studies have demonstrated that treatment with tirzepatide results in significant improvement in HgbA1c as well as meaningful weight loss. Although the loss of skeletal muscle mass has been well described with the use of GLP-1 receptor agonists, there is little information regarding the effect of dual GLP-1/GIP receptor agonist tirzepatide on skeletal muscle mass. We provide a detailed case study and a literature review on this topic.