Rewiring Cravings: Could GLP-1 Drugs Curb Alcohol Addiction As Well as Appetite?

Over the past decade, glucagon-like peptide-1 receptor (GLP-1R) agonists have transformed the treatment of type 2 diabetes and obesity.

Anti-diabetic drugs such as semaglutide and liraglutide not only improve blood sugar control but are becoming widely adopted for weight management in those without diabetes, working by slowing gastric emptying, increasing insulin secretion, and reducing appetite.

Large clinical trials have demonstrated their effectiveness, and they are now increasingly prescribed for diabetes and weight management.

With their growing clinical adoption, researchers have become interested in the effects of these drugs beyond metabolism. Patients frequently report changes in appetite, food preferences, and alcohol consumption—observations that have raised new questions about how GLP-1R agonists act in the brain.

This interest has shifted attention toward whether targeting brain circuits that regulate motivation and reward could help treat overeating and substance use disorders.

Dr. Linda Rinaman, a neuroscientist at Florida State University whose work focuses on brain–body communication, spoke with Technology Networks to discuss how GLP-1R agonists access the brain and what this might mean for behaviors such as binge eating or addiction.

GLP-1 signaling in the brain

GLP-1 is best known as a gut hormone. After a meal, it is released from specialized intestinal cells and enters the bloodstream, where it helps regulate blood sugar and appetite. However, GLP-1 is also produced inside the brain, and this central source turns out to be vital for understanding how GLP-1R agonists influence behavior.

“The GLP-1R in the brain is the same as the GLP-1R in the periphery, although the source of GLP-1 that binds to these receptors differs,” Rinaman explained. “Peripheral GLP-1R is bound by GLP-1 released from intestinal secretory cells.”

Although small amounts of circulating GLP-1 may reach regions that lie outside the blood–brain barrier, most brain GLP-1 signaling originates locally.

“While it is possible that intestinally-derived GLP-1—which enters the blood circulation but is rapidly degraded—can access a small subset of GLP-1Rs that lie outside the blood-brain barrier, the natural source of GLP-1 that binds to GLP-1R in the brain comes from within the brain itself,” said Rinaman.

This brain-derived GLP-1 is produced by a small group of neurons in the caudal brainstem.

Despite their limited number, “neurons in the caudal brainstem that synthesize GLP-1 have widely-branching axons that innervate multiple brain regions where GLP-1R is expressed,” Rinaman noted.

Understanding where GLP-1R agonists act in the brain is essential for predicting both their benefits and risks; animal studies have identified two regions as particularly important.

“Preclinical evidence in rats and mice points to the caudal brainstem and the mediobasal hypothalamus as sites that are necessary and sufficient for the ability of systemically administered GLP-1R agonists to reduce food intake,” Rinaman said. “These brain regions are accessible from the circulation.”

 

 

Since these areas lie at the interface between the brain and the body, drugs administered outside the brain can still influence neural activity there.

Implications for overeating and addiction

Animal studies show that activating GLP-1 signaling in these regions has clear behavioral consequences.

“Preclinical evidence supports the view that GLP-1 acts at these brain receptors to reduce food intake and other motivated behaviors, and also to activate physiological and behavioral stress responses,” Rinaman said.

Experiments in rodents show that stimulating central GLP-1 signaling suppresses eating, alters food-seeking behavior, and engages stress-related pathways.

Many behaviors linked to overeating and addiction are driven by the brain’s reward system, particularly pathways that use the neurotransmitter dopamine. The mesolimbic system, which includes brain regions such as the ventral tegmental area and nucleus accumbens, plays a central role in motivation and reinforcement.

“Preclinical evidence in rats and mice indicates that GLP-1 and/or GLP-1R agonists act within the brain to reduce the reinforcing value of palatable foods and ‘drugs of abuse’ by altering dopamine signaling within the mesolimbic reward system,” Rinaman explained.

GLP-1R activation in these regions reduces intake of high-fat or sugary foods and decreases self-administration of substances such as alcohol, cocaine, and nicotine, in animal models.

These findings have evoked interest in whether GLP-1R agonists could be repurposed to treat substance use disorders in humans.

Early clinical observations and small studies hint at reduced alcohol intake among patients taking GLP-1R agonists, although large, controlled trials are still limited.

However, “GLP-1R agonists also can promote nausea and malaise, a ‘side effect’ that can be difficult to disentangle from a specific effect to reduce reward-related behavior,” Rinaman cautioned.

If a drug makes someone feel unwell, reduced consumption of food or alcohol may reflect aversion rather than true changes in reward processing. Distinguishing between these possibilities remains a major hurdle.

Side effects and translational challenges

Despite their promise, several challenges must be addressed before GLP-1R agonists can be repurposed for addiction-related behaviors.

“We need to better understand how to control the negative side effects of GLP-1R agonists (i.e., nausea/emesis),” explained Rinaman.

Broader brain access may also come at a cost. “We need to keep in mind that increased brain penetrance of GLP-1R agonists might lead to a host of new side effects, such as anxiety and increased stress responses,” Rinaman warned.

In clinical settings, patients often need higher doses over time to maintain weight loss or glycemic control. On this point, Rinaman noted: “It’s not clear whether that is due to receptor desensitization or other compensatory mechanisms—either neural, physiological, or behavioral.”

There is also limited data on how chronic treatment reshapes brain circuits.

“Additional preclinical work would be quite valuable to address this,” added Rinaman.

Promise with caution

GLP-1R agonists offer an example of how drugs developed for metabolic diseases can influence brain-based behavior. These compounds may hold promise not only for obesity but also for overeating and substance use disorders.

At the same time, side effects, limited tools for tracking drug access to the brain, and gaps in understanding long-term neural adaptations all complicate translation to the clinic.

“We need to better understand the central bioavailability of GLP-1R agonists after systemic administration. Current techniques to visualize brain access are likely too crude to reveal all the potential sites of direct action,” said Rinaman.

Moving forward, improved imaging methods, carefully designed clinical trials, and mechanistic studies in animal models will be needed.

With cautious optimism, GLP-1R agonists may expand from metabolic medicines into a new class of brain–body therapeutics, but only if their neural effects are fully understood.