GCG and Parkinson disease: Since findings from these preclinical studies were promising, GLP-1 analogs are now being investigated in humans in clinical trials for treatment of Alzheimer’s disease (Egefjord et al., 2012; Gejl et al., 2016) and Parkinson’s disease (Aviles-Olmos et al., 2013; Athauda et al., 2017, 2019).