Semaglutide as a potential neuroprotective agent for neurological and neurodegenerative disorders: Mechanisms, preclinical evidence, and translational challenges and opportunities.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are established treatments for metabolic disease, with growing evidence suggesting neuroprotective potential in central nervous system (CNS) disorders. In preclinical models of Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and stroke, semaglutide has been reported to reduce neuroinflammatory and oxidative stress markers and improve selected pathological or behavioral outcomes, although the specific effects vary by model and indication. However, significant translational challenges remain. The Phase 3 EVOKE and EVOKE+ trials in early symptomatic AD failed to meet primary cognitive endpoints, although biological target engagement was reported, with improvements in selected AD-related biomarkers including p-tau181, p-tau217, neurogranin, YKL-40, and plasma hsCRP. This dissociation between biomarker changes and clinical benefit may reflect treatment timing, advanced neurodegeneration, limited CNS exposure, endpoint sensitivity, or other factors. In contrast, observational studies suggest an association between semaglutide or GLP-1 RA exposure and lower dementia-related risk in at-risk populations, although preservation of cognitive reserve has not been directly demonstrated and causality has not been established. This review evaluates the current mechanistic, preclinical, and emerging clinical evidence for semaglutide across neurodegenerative and neuroinflammatory disorders, with emphasis on distinguishing semaglutide-specific findings from broader GLP-1 RA class effects and identifying key translational limitations. Collectively, current evidence supports continued investigation of semaglutide as a potential neuroprotective strategy, while highlighting the need for earlier intervention studies, improved understanding of CNS target engagement, and further clinical validation.