GLP-1 receptor agonists in neurological diseases: mechanisms and therapeutic prospects from metabolism to neuroprotection.

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are widely used metabolic therapies for type 2 diabetes and obesity, with well-established cardiovascular benefits. Beyond glycemic control, accumulating experimental and clinical evidence suggests that GLP-1RAs exert pleiotropic actions relevant to neurological diseases. Metabolic dysfunction, chronic inflammation, oxidative stress, mitochondrial impairment, and neurovascular injury represent convergent mechanisms that contribute to neurodegeneration, cerebrovascular pathology, and metabolism-related brain disorders. Notably, these processes overlap with pathways modulated by GLP-1 signaling across systemic and central compartments. GLP-1 receptors are expressed in neurons, glial cells, and components of the neurovascular unit, providing a biological basis for possible neurological effects. Preclinical studies suggest that GLP-1RAs can reduce neuroinflammation and oxidative stress, support mitochondrial function, and help maintain blood-brain barrier integrity. Clinical findings, however, remain inconsistent. Studies in Parkinson's disease have reported encouraging signals, but biomarker evidence for disease modification is still limited. In Alzheimer's disease, clinical trials have produced mixed or negative results. These differences may reflect disease stage, patient selection, drug-specific pharmacology, central nervous system exposure, endpoint sensitivity, and treatment duration. Overall, GLP-1RAs may influence neurological disease through metabolic, inflammatory, and vascular pathways, but their clinical role remains unsettled. Future studies should use biomarker-informed designs, prespecified neurological endpoints, appropriate drug selection, and sufficiently long follow-up to determine which patients and disease stages are most likely to benefit.