In recent years, a new class of medications originally developed to treat diabetes and promote weight loss—such as Ozempic, Wegovy, Zepbound, and Mounjaro—has gained widespread attention not only for their effectiveness in managing blood sugar and reducing appetite but also for their surprising effects on substance cravings beyond food. Specifically, many individuals taking these drugs have reported a marked decrease in their desire for alcohol and nicotine. While anecdotal reports have suggested these benefits, the underlying biological mechanisms have remained elusive. A recent preliminary study published in Scientific Reports sheds light on how these medications might reduce alcohol consumption and the subjective feeling of intoxication, potentially paving the way for new treatments for addiction.
The key to understanding these effects lies in the drugs’ ability to mimic a natural gut hormone called glucagon-like peptide 1 (GLP-1). GLP-1 is involved in regulating insulin release and signaling fullness to the brain. The primary way GLP-1 receptor agonists promote weight loss is by enhancing feelings of satiety, causing individuals to eat less. Researchers have long hypothesized that since the brain’s pathways governing pleasure and satiety overlap, GLP-1 medications might also dampen the reward signals associated with addictive substances like alcohol. However, the new study argues that to fully grasp these drugs’ impact on substance use, it’s critical to consider their effects not only in the brain but also throughout the body, particularly in the gut.
Alex DiFeliceantonio, an appetitive neuroscientist at Virginia Tech and co-author of the study, emphasizes the importance of examining the whole-body effects of GLP-1 drugs. “There’s a lot of action in the brain, but what we were trying to argue in our paper is that there also is probably action in the gut,” she explains. One well-known physiological effect of GLP-1 receptor agonists is the slowing of gastric emptying—the process by which food and liquids move from the stomach into the small intestine. By delaying gastric emptying, these medications cause food to stay longer in the stomach, which contributes to the feeling of fullness and limits meal size.
This delay in gastric emptying may also influence how alcohol is absorbed and processed by the body. Unlike many nutrients, alcohol is poorly absorbed in the stomach and primarily enters the bloodstream through the small intestine. Therefore, if the passage of alcohol from the stomach to the intestine is slowed, it may take longer for alcohol to reach the bloodstream and, ultimately, the brain. This slower absorption could reduce the intensity and speed of alcohol’s rewarding effects, which are closely tied to the risk of addiction.
To test this hypothesis, DiFeliceantonio and her colleagues conducted a small experimental study involving 20 participants, half of whom were taking a GLP-1 receptor agonist for weight loss, while the other half served as a control group not taking the medications. None of the participants had alcohol use disorder. In a controlled laboratory setting designed to resemble a bar, each participant consumed three doses of vodka mixed with juice over one hour, calibrated according to their body size to reach a breath alcohol content (BrAC) of 0.08 percent—the approximate legal limit for driving in the United States.
The researchers carefully measured breath alcohol levels and asked participants to rate how intoxicated they felt over a four-hour period. What they observed was striking: in the first 20 to 30 minutes after drinking, participants taking GLP-1 receptor agonists had significantly lower breath alcohol content and reported feeling less drunk compared to those in the control group. Although after about an hour both groups reached similar alcohol levels, the initial delay in alcohol absorption appeared to reduce the early rewarding effects of drinking. Importantly, these differences in intoxication were not explained by changes in blood glucose levels or by the nausea often associated with GLP-1 drugs, suggesting that the slowed gastric emptying was a key factor.
While the study’s findings are promising, the authors acknowledge several limitations. The sample size was small, and participants were using different GLP-1 medications at varying doses, which could influence the results. Ideally, future research would focus on a larger, more uniform group to clarify the effects of specific drugs and dosages. Nonetheless, addiction experts like Carolina Haass-Koffler, an associate professor of psychiatry at Brown University who was not involved in the study, praise the research for its innovative focus on the systemic, whole-body nature of alcohol use disorder