Liraglutide has been approved by the Food and Drug Administration (FDA) to treat adults with Type 2 Diabetes (T2D) and to treat obesity, but it is considered investigational in this study, as it has not been approved for use in patients with PD. Liraglutide belongs to a class of medications able to stimulate receptors of glucagon-like peptide 1 (GLP-1), a naturally occurring peptide found throughout much of the brain and able to increase the incretin effect in patients with T2D, stimulating the release of insulin. Liraglutide can reduce systemic and brain insulin resistance, an abnormality that could help drive PD pathogenesis. Indeed, impaired insulin signaling in the brain can cause or exacerbate many brain pathologies and behavioral abnormalities seen in PD. Another GLP-1 agonist, named exenatide, has been evaluated in patients with PD, showing significant improvement of motor and cognitive symptoms. There is reason to believe that liraglutide may prove superior to exenatide in treating PD.