In April of last year, neuroscientist Sue Grigson received an unexpected e-mail. The message came from a man who spent years battling addiction—first opioids, then the very medication prescribed to help him stop. While searching online for answers, he found Grigson’s research showing that certain anti-obesity drugs appeared to reduce drug dependency in laboratory animals. Inspired, he attempted to quit again, this time while taking semaglutide, a GLP-1 medication widely known by its commercial name, Ozempic. He told Grigson that, for the first time since reaching adulthood, he was free from both drugs and alcohol.
Stories like his have multiplied rapidly across social media, clinic waiting rooms, and news reports. Many people taking semaglutide (also sold as Wegovy) or tirzepatide (marketed as Mounjaro and Zepbound) for diabetes or weight loss say they also experienced unexpected relief from long-standing addictions such as smoking, drinking, or drug use. Recently, emerging clinical data has begun giving weight to these anecdotal accounts.
A major milestone came earlier this year when a research team led by psychologist Christian Hendershot, now at the University of Southern California, published results from a landmark randomized trial. Their study found that weekly semaglutide injections significantly reduced alcohol consumption among people diagnosed with alcohol-use disorder. With more than a dozen clinical trials now underway worldwide, scientists expect an influx of results soon.
At the same time, neuroscientists are mapping out how these medications act on receptors in brain regions tied to motivation, reward, and craving. Their findings suggest that GLP-1 drugs reduce urges for alcohol, nicotine, opioids, and cocaine through some of the same pathways that regulate hunger and overeating. According to psychopharmacologist Roger McIntyre at the University of Toronto, the brain’s reward system operates similarly across substances and stimuli. “Food, drugs, or other rewarding experiences all activate overlapping circuits,” he explains. Because of this shared biology, some scientists are also evaluating whether GLP-1 drugs could help treat depression or dementia.
Despite the excitement, researchers emphasize that this field is still young. Neuroimaging expert W. Kyle Simmons at Oklahoma State University cautions that the ultimate test is whether these medications prove both effective and safe for people with substance-use disorders. Still, some specialists call the early signs remarkable. Addiction biologist Elisabet Jerlhag Holm notes that no new category of addiction medication has been approved in decades. If GLP-1 drugs succeed in large-scale trials, she says, “it could be revolutionary.”
Slow Beginnings Before a Scientific Surge
The current enthusiasm surrounding GLP-1 drugs and addiction has taken years to develop. Originally created to manage blood sugar in people with type 2 diabetes, these medications mimic the hormone GLP-1. Researchers soon discovered another effect: they significantly reduced appetite and supported substantial weight loss. This happens because the drugs act not only on receptors in the pancreas and gut, but also on neural regions involved in reward and motivation.
Around the early 2010s, Jerlhag Holm began investigating whether GLP-1 drugs could reduce urges beyond food. Her group published studies showing that these medications curbed addictive behaviors in rodents dependent on alcohol, nicotine, and stimulants such as cocaine and amphetamine. They even showed reduced relapse-like behaviors in animals that had previously abstained.
Yet, at the time, the research community mostly overlooked these results, and pharmaceutical companies showed little interest. Holm recalls feeling isolated in her findings.
That changed when physician-scientist Lorenzo Leggio at the US National Institutes of Health took notice. After examining clues that GLP-1 influenced addictive behavior in humans, he partnered with Holm in 2015 to explore the hormone’s role in alcohol dependence. They discovered that a genetic variant of the GLP-1 receptor was linked to heavier drinking. Later, using post-mortem brain tissue, Leggio’s team found that individuals with alcohol-use disorder had elevated levels of GLP-1 receptors in reward-related regions of the brain—a potential compensatory response to alcohol reducing GLP-1 production.
These discoveries helped build momentum. But the issue reached public attention only in 2023, when a feature story in The Atlantic profiled people who said semaglutide had unexpectedly reduced their desire to smoke or drink. The piece prompted a wave of media inquiries and pushed the science into the spotlight.
Initial clinical trials were mixed. In 2022, psychiatrist Anders Fink-Jensen at the University of Copenhagen tested exenatide—an older GLP-1 drug—and found it did not significantly reduce heavy drinking among individuals with alcohol dependence. A similar 2023 trial in Switzerland found that dulaglutide did not help smokers quit.
Some studies, however, revealed promising effects. A small trial led by Grigson and psychologist Scott Bunce showed that liraglutide lowered opioid cravings by about 40% in people with opioid-use disorder. Functional MRI scans from other studies also indicated that GLP-1 drugs dampened neural responses to alcohol cues.
Importantly, first-generation GLP-1 medications such as exenatide and dulaglutide are far weaker than newer compounds like semaglutide and tirzepatide. These newer drugs bind more effectively to receptors, stay active longer, and have shown benefits across multiple health conditions. This raises the question: could the modern versions meaningfully alter addictive behavior?
A New Wave of Trials and High Expectations
Multiple clinical studies are now exploring the potential of second-generation GLP-1 medications in addiction treatment. Fink-Jensen’s team has already completed a trial involving 108 participants with obesity and alcohol-use disorder, testing high-dose semaglutide commonly prescribed for weight loss. The results are expected in early 2026.
In the United States, Leggio, Simmons, and psychologist Joseph Schacht are conducting coordinated trials. These studies examine injected semaglutide (in both high-dose Wegovy and lower-dose Ozempic forms) as well as the pill version, Rybelsus. Schacht believes oral medication may appeal to individuals who associate needles with past drug use and may feel uneasy about injections.
All three teams use fMRI scans to study how participants’ brains react to alcohol-related images before and after treatment. These neural snapshots may reveal how the medication affects craving and might even help identify which patients respond best.
How GLP-1 Drugs Influence the Brain
Decades of research show that addictive substances and rewarding experiences trigger similar neural circuits. These networks extend from the ventral tegmental area—where dopamine-producing neurons reside—to the nucleus accumbens, which interprets dopamine as pleasurable reinforcement. Each exposure to alcohol, nicotine, or opioids boosts dopamine release, strengthening the desire to repeat the behavior.
GLP-1 receptors are located throughout these circuits. When activated, they appear to reduce dopamine signaling, making the rewarding effects of substances feel less intense. In this way, semaglutide and similar drugs may blunt compulsive urges.
Animal studies also highlight the role of stress circuits. GLP-1 activity in regions like the amygdala can reduce stress hormones associated with withdrawal and anxiety. This dual impact—reducing both craving and stress—might help explain why relapse behavior declines in rodent models.
Although each substance may involve slight variations, the overall mechanism appears consistent. For addiction researchers, this universality is striking. Current medications target specific substances, such as nicotine or opioids, and often produce only modest improvements. By acting on broader reward pathways, GLP-1 drugs could theoretically treat multiple forms of addiction, including people who struggle with more than one substance at a time.
Beyond Addiction: A Possible Link to Cognition
The overlap between reward pathways and cognitive processes has prompted researchers to test GLP-1 drugs for neurological conditions such as Alzheimer’s disease and depression. But clinical trials so far have been mixed. In two recent phase III trials, oral semaglutide failed to slow cognitive decline in people with Alzheimer’s disease. Another trial involving 72 participants with depression found no significant improvement in overall cognition after 16 weeks, though some participants did show better attention and memory.
Even so, some clinicians remain hopeful that the drugs might assist with cognitive symptoms that traditional antidepressants rarely address.
Remaining Challenges and the Road Ahead
Experts caution that regulatory approval for treating addiction is still years away. Large-scale trials must first demonstrate that GLP-1 drugs meaningfully reduce substance use in ways that improve daily life—not just brain activity or self-reported cravings.
Weight loss is another concern. Many people with substance-use disorders already experience unstable eating patterns or appetite fluctuations. Because GLP-1 medications commonly suppress hunger, there is a risk of excessive weight loss or malnutrition. To avoid these complications, current trials mainly enroll participants who are overweight or obese.
Major pharmaceutical companies have recently joined this field of research. Novo Nordisk is studying whether semaglutide can reduce alcohol consumption and liver damage in people with alcohol-related liver disease. Eli Lilly is testing a new drug, similar to tirzepatide, in 300 participants with alcohol-use disorder.
Meanwhile, online communities continue to share personal stories from people who say the medications helped them quit nicotine, opioids, alcohol, and even non-substance-related behaviors like compulsive shopping or gambling. Researchers treat these stories with caution, noting that lifestyle changes associated with weight loss could influence behavior independently of the medication.
Still, for scientists like Grigson, these stories underscore the importance of her work. She and Bunce recently launched a 200-person trial of semaglutide for opioid-use disorder—the largest academic study exploring GLP-1 drugs in addiction to date.
“People are hopeful,” Grigson says. “And that hope matters.”
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