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What do GLP-1 drugs really tell us about the brain's reward system?

Anecdotal reports suggest drugs like Ozempic may curb not just appetite but also impulsive or addictive behaviour, hinting at links between metabolic health and our brains

By David Robson

26 March 2025

91av. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

SPL; Eyevine

“I just cannot believe how I don’t crave alcohol anymore!” writes one person. Others declare: “Took my first shot… have not had a drink or cigarette since,” and “I love coffee but I’ve noticed that I cannot finish a cup anymore.”

These quotes were all collected in a recent study led by Davide Arillotta at the University of Florence, Italy, from Reddit’s weight-loss forums. Here, you will find many people rhapsodising about the benefits of drugs like Wegovy and Ozempic. That these treatments are helping people curb their eating should be no surprise: that is exactly what they are meant to do, by mimicking the satiety hormone GLP-1 (see “How they work”, below).

This article is part of a special series investigating the GLP-1 agonist boom. Read more here.

Among the comments, however, you will frequently find reports of other – wholly unexpected – behavioural changes. According to these accounts, when taking these drugs, the urge to drink alcohol, smoke and even shop compulsively plummets (but not libido, though anecdotal reports on this subject elsewhere online are mixed). Such tales are becoming familiar to prescribing physicians.

If this anecdotal data can be supported by controlled clinical trials, it may tell us a lot about how the brain processes anticipation and reward – and could also suggest whole new ways of dealing with addiction. By targeting areas of the brain responsible for reward signals from food, GLP-1 drugs might also reduce the rewards people get from other things, such as addictive substances. But what does the current evidence show about these complex behavioural processes?

First, we need to understand how drugs…

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