GLP1R and obesity due to melanocortin 4 receptor deficiency: Tirzepatide, a dual GIPR/GLP-1R agonist approved for T2D and obesity, has shown preclinical neurobiological effects consistent with neuroprotection in models of diabetic neurodegeneration, Alzheimer-type amyloidosis, and Parkinson’s disease; however, results are not uniform across studies and, to date, no tirzepatide trials in PD are registered [82–85].