GLP1R and obesity due to melanocortin 4 receptor deficiency: The first GLP-1 RA approved for weight loss in overweight and obesity, liraglutide, received authorization in the United States (US) market in 2014 [16], and since 2022, 2 GLP-1 RAs (liraglutide, semaglutide) have also been approved for weight loss in European countries [14].