Efficacy of GLP-1 receptor agonists in Parkinson’s disease: a systematic review and exploratory network meta-analysis of randomized controlled trials

Current therapies for Parkinson’s disease lack proven disease-modifying effects. Glucagon-like peptide-1 receptor agonists (GLP-1RAs), developed for type 2 diabetes, have shown potential neuroprotective properties. Their comparative efficacy in Parkinson’s disease remains unclear. A systematic search (inception–February 2026) identified randomized controlled trials evaluating GLP-1RAs in Parkinson’s disease. Pairwise and frequentist random-effects network meta-analyses were performed. The primary outcome was MDS-UPDRS Part III (ON state). Five trials (n = 708) were included. Pairwise meta-analysis showed no significant overall improvement in MDS-UPDRS Part III (MD –2.00; 95% CI –5.46 to 1.46; I² = 80.5%). Network meta-analysis demonstrated significant ON-state motor improvement with Exenatide 20 µg/day (MD –9.80; 95% CI –14.47 to –5.13) and Lixisenatide 20 µg/day (MD –3.08; 95% CI –5.31 to –0.85). No significant effects were observed for MDS-UPDRS Part III (OFF-state) or other domains (Parts I, II, and IV; ON-state). NLY01 at 5 mg/week improved PDQ-39, while NMSS showed dose-dependent divergence. Gastrointestinal adverse events were more frequent with GLP-1RAs. GLP-1 receptor agonists may provide dose-specific motor benefits in Parkinson’s disease, but evidence for broader clinical improvement is limited. Larger, longer-duration trials are needed.