Scientists are probing brain circuits affected by GLP-1 medicines such as Ozempic, Wegovy, Mounjaro, and Zepbound to preserve weight-loss benefits while curbing nausea. The findings, presented at Neuroscience 2025, outline strategies that could refine treatments for obesity and type 2 diabetes.
Medications that act on the glucagon-like peptide-1 (GLP-1) system are now common in treating type 2 diabetes and obesity. They mimic a gut hormone released after meals to signal the brain and reduce hunger, but up to 40% of users report nausea and vomiting—side effects that can lead patients to stop therapy, according to the Society for Neuroscience. The new work, to be highlighted at Neuroscience 2025 in San Diego, investigates whether appetite and weight-loss effects can be separated from those adverse symptoms. (eurekalert.org)
Common brands in this class include semaglutide (Ozempic, Wegovy), liraglutide (Victoza, Saxenda), and tirzepatide (Mounjaro, Zepbound). Researchers are mapping how these drugs engage brain networks involved in nausea, thirst, and reward-driven eating to inform safer designs. (sciencedaily.com)
Key findings presented include:
- In obese rats, pairing low-dose tirzepatide—a dual agonist that activates GLP-1 and GIP receptors—with oxytocin produced an 11% body-weight reduction over 28 days, versus about 6–7% with either agent alone, without an increase in kaolin consumption (a proxy for nausea). (James E. Blevins, University of Washington.) (eurekalert.org)
- In mice, targeting GLP-1 action to the area postrema—the brain’s vomit center—produced both weight loss and nausea, suggesting this region drives beneficial and aversive responses to GLP-1 drugs. (Warren Yacawych, University of Michigan.) (sciencedaily.com)
- Activating GLP-1 receptors on central amygdala cells dampened dopamine signaling along a reward circuit to the ventral tegmental area, curbing pleasure-based eating in mice. (Ali D. Güler, University of Virginia.) (eurekalert.org)
- GLP-1 receptor agonists also suppressed thirst in rat models, implicating the median preoptic area in this effect. (Derek Daniels, University at Buffalo.) (sciencedaily.com)
Lorenzo Leggio, MD, PhD, clinical director at the National Institute on Drug Abuse, said the medicines affect the brain beyond metabolic disease, “via mechanisms that are still not fully understood,” and may aid conditions with overlapping neural pathways, including binge eating and addiction. (eurekalert.org) Leggio’s role as NIDA clinical director is confirmed by the institute. (irp.nida.nih.gov)
According to the Society for Neuroscience, the studies were supported by the National Institutes of Health, the Department of Veterans Affairs, and private organizations. The authors emphasized that by pinpointing the brain circuits behind appetite, reward, thirst, and nausea, future therapies could maintain weight-loss efficacy while minimizing intolerable side effects. (sciencedaily.com)
