Many Americans are using weight loss drugs such as Ozempic and Mounjaro to shed pounds, with estimates from RAND suggesting 11.8 percent of adults used GLP-1 antagonists in 2025. (It was published midway through the year, so it may not quite paint the full picture.) And yet early research appears to suggest it is not just the waistline affected by the use of semaglutides and other GLP-1s. The drugs may also be changing the way the brain functions.
Preliminary research investigating the impact of GLP-1 receptor antagonists on the brains of adolescent girls diagnosed with Polyendocrine Metabolic Ovarian Syndrome (formerly PCOS, now PMOS) suggests that the drugs increase brain connections related to the hypothalamus and salience network. And it does so remarkably quickly.
Allison Shapiro, Assistant Professor of Pediatrics-Endocrinology at the University of Colorado Anschutz, who led the research, told Discover that the fact that drugs trigger changes in this part of the brain “makes sense” — “how quickly it’s happening is what is most impressive.”
The research has not yet been published or undergone peer review. Shapiro describes it as a proof-of-concept and hopes the results will make the case for larger trials that investigate the impact of semaglutides on the adolescent brain.
Explore All OptionsInvestigating The Neurological Impact Of GLP-1s
There are already a handful of studies examining the impact of GLP-1s on brain function in adults, including one in the Journal of Alzheimer’s Disease Reports that suggests the drugs may even improve cognitive function and brain outcomes. And it is known they modulate the hypothalamus to suppress appetite.
Shapiro was interested in exploring what taking weight-loss drugs does to the teenage brain, which emphasizes reward, has a less developed prefrontal cortex (necessary for cognitive control), and is generally more malleable and receptive to change. A small study led by Dr. Melanie Cree that set out to investigate the impact of semaglutides on the livers of adolescents with PMOS provided the perfect opportunity.
The randomized control trial included two groups of girls (average age of 15) with obesity and PMOS. The first group was given a low dose of oral semaglutide (Reybelsus), starting at 3 milligrams and increasing to a maximum of 7 milligrams (though not all received the highest dose). The second group received regular diet counseling focused on healthy eating, led by a dietitian.
Each received a full body and brain scan via an MRI before and after four months of treatment. These were taken at resting state, meaning the participants were inactive for the duration of the scan. Shapiro told Discover that 13 participants were scanned, but once the quality of data was factored in, the researchers were left with results from five girls in each group.
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What Did The Results Show?
The scans revealed an increase in the number of brain connections in brain regions linked to appetite.
“The hypothalamus actually increases its connectivity or its communication to regions of the salience network,” said Shapiro. “The salience network is very important, especially in eating behaviors, because it basically tells us what to do.”
This change, Shapiro explained, was accompanied by a sharp reduction in weight of approximately 10 percent. While the results present an interesting correlation (note: not causation), Shapiro said the fact that the two changes occurred over the same four-month period suggests it is “clinically relevant.”
Still, it is less the fact that the changes happened in the first place and more the speed at which they occurred that Shapiro found particularly intriguing.
Expanding Future GLP-1 Research
With just five participants in each group, the study is exceptionally small. Shapiro hopes to expand the research by conducting a larger trial with a larger sample size and greater participant diversity. This, she believes, will enable researchers to look at how GLP-1s affect brain development throughout adolescence and into young adulthood.
She believes that in the coming years, we will learn more about the long-term health impacts (and side effects) of taking Ozempic and other GLP-1s.
“We just don’t know what happens to the human body when we suppress appetite for so long, when we slow down gut motility,” said Shapiro. “We are in potentially one of the largest natural human experiments.”
This article is not offering medical advice and should be used for informational purposes only.
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in the American Journal of Medicine: Mechanisms of GLP-1 Receptor Agonist-Induced Weight Loss: A Review of Central and Peripheral Pathways in Appetite and Energy Regulation
- This article references information from RAND: New Weight Loss Drugs
- This article references information from a study published in the Journal of Alzheimer’s Disease Reports: Exploring the link between GLP-1 receptor agonists and dementia: A comprehensive review
