GLP1R and Alzheimer disease: Clinical trials investigating commercially available GLP-1R agonists as treatments for PD and AD have already been completed, with encouraging results comprising improved off-medication motor scores, motor ability, and cognitive function in PD patients [40,41,42,43], as well as improved brain glucose metabolism [44] and reduced amyloid-β 1-42 concentration in neuronal-derived extracellular vesicles [45] in AD patients.