GCG and Parkinson disease: In addition to its effects on metabolic regulation, GLP-1, when synthesized within the brain, exhibits neuroprotective properties.397,427,431 A clinical trial titled “Liraglutide in Early Parkinson’s Disease” was published in the New England Journal of Medicine, exploring the effects of liraglutide on patients with early-stage PD diagnosed within the last three years.432 The research was a 14-month Phase II double-blind randomized controlled trial.