Dhruv Khullar: Last year, I met a woman I'll call Mary. Mary was 13 when she started drinking, and soon she could drink 18 beers in a sitting and barely seem buzzed. Her days became a blur of inebriation and hangover. Mary wanted to stop drinking. She tried alcohol rehab, Alcoholics Anonymous, a medication called Antabuse. None of them worked for her.

Dhruv Khullar: One day, Mary was at a bar with a friend who also drank heavily. But that evening, Mary noticed that her friend had hardly sipped her drink. Her friend told her that she started taking Ozempic, and now she could barely drink two beers at a time. Mary was perplexed. She'd always thought of Ozempic as an obesity medicine. What did it have to do with drinking? But she decided to enroll in a nearby clinical trial that was studying whether GLP-1 medications like Ozempic could help people with alcohol addiction. Every week, researchers blindfolded her and injected her with a solution. Either Ozempic or a placebo. Within weeks, Mary lost her taste for beer. She switched to white wine, and then she stopped drinking altogether.

Dhruv Khullar: Many people talk about Ozempic as getting rid of the food noise inside their heads. Those intrusive, unwanted, repetitive thoughts about eating. For Mary, it cleared out alcohol noise. It started to moderate her desire for drinking. It turned what was an overpowering emotional response into something that could be seen from a distance. Suddenly, she had the mental space to make changes in her life that she had long wanted to. She started exercising. She improved her diet. She ended a difficult relationship. "People know how much GLP-1s affect your body," she told me. "I don't think they realize how much they affect your mind."

Dhruv Khullar: Now as a doctor I have long wished that we had more to offer people who are struggling with an addiction. And hearing Mary's story, it's hard to overstate just how striking it was.

Dhruv Khullar: GLP-1, or glucagon-like peptide-1, was first discovered way back in the 1980s. Scientists thought that it might be helpful to manage diabetes, but because the naturally-occurring version of the molecule broke down within minutes, it was hard to turn it into a drug. The big break didn't come until years later, when a scientist who was studying Gila monsters, of all things, found that the lizard's venom contained a similar peptide, and that peptide could hang around for hours. His discovery catalyzed what would become the GLP-1 revolution.

Dhruv Khullar: Now for a long time, GLP-1 was thought to be mainly about digestion, but it's now clear that the medications affect much more than eating. They might have some of their most surprising effects not in the gut, but in the brain. Stories like Mary's have led scientists to consider whether these medications could be helpful for all sorts of addictions, from alcohol and cocaine to gambling and compulsive shopping. Research has found that GLP-1s might help people stop smoking, reduce their cravings for opioids, lead them to consume fewer drinks. As one neuroscientist put it, GLP-1s might be telling us that there is some type of universal pathology when it comes to addiction, and that they are part of how we fix it.

Dhruv Khullar: Now that is a tantalizing prospect, that there's a general-purpose key that unlocks the path to moderation. But that’s what GLP-1s seem like they could be: moderation molecules. They don't extinguish our desires, but they help us keep them in check. And no one knows exactly why.

Dhruv Khullar: One possibility is that they modulate what's called the brain's mesolimbic pathway, sometimes referred to as the reward system. Alcohol, nicotine, cocaine, social media -- they all increase dopamine release in that pathway. And GLP-1s -- they might be limiting the spikes of dopamine. So mice that are on the medications and given cocaine -- they have smaller surges of dopamine, but they otherwise seem to maintain adequate amounts of the neurotransmitter. GLP-1s could be calming the water without draining the pool.

Dhruv Khullar: At the other end, GLP-1s might make it easier to stop using a drug. Research that's currently under review has found that animals that are addicted to opioids and given a GLP-1s, they have less activity in a part of the brain that's involved with withdrawal. So again, these medications could lead to moderation, not just because they make a drug less pleasurable, but because they make abstinence less painful.

Dhruv Khullar: Now at this point, we should probably moderate our own enthusiasm about the moderating effects of these medications. Like any drug, GLP-1s won’t work for everyone. In fact, for some people, these so-called “moderation molecules” could have an alter ego as a desire dampener. Maybe some people lose interest in drugs or alcohol or food because they lose interest in pretty much everything -- a condition known as anhedonia. It's also true that addiction is often a lifelong battle, but many people who start on a GLP-1 -- they come off it within months, whether because of side effects or costs or access. And even people who do manage to stay on the medications might ultimately develop a tolerance to them such that their cravings for a drug ultimately return.

Dhruv Khullar: And yet it is hard not to get excited about the potential for GLP-1s to treat addiction when you consider how little progress we have made. Every year, tens of thousands of Americans die of an opioid overdose. Since the turn of the century, alcohol-related deaths have more than doubled, and it has been 20 years since the FDA last approved a medication for alcohol use disorder.

Dhruv Khullar: The winding path of GLP-1s from Gila monster peptide to diabetes medication to obesity drug to potential addiction treatment -- it is a story of hope. But it's also a story with a lesson. The hope is that more people will gain the power to bring their wants and their motivations and their behaviors into greater harmony, and they will live many more years in good health as a result.

Dhruv Khullar: The lesson is about the unpredictability of medical progress. Discoveries like this one remind us why scientific curiosity, especially the kind that can seem obscure or impractical, why it matters so deeply. Because we don't know where the next big innovation will come from. We might not even recognize it when we first see it.

Dhruv Khullar: But now GLP-1s are forcing us to reconsider not just the modern science of addiction, but ancient wisdom about restraint. For thousands of years, we have seen moderation as a moral achievement. Aristotle argued that the path to a life well-lived runs through moderation. Courage rests somewhere between cowardice and recklessness, generosity between stinginess and extravagance. He's often quoted as saying "It is best to rise from life as though from a banquet. Neither drunken nor thirsty."

Dhruv Khullar: Well, Aristotle never had a Dorito. He didn't have Krispy Kreme or McDonald's. He couldn’t flip open TikTok and Instagram -- there weren't algorithms that were fracking his attention, and ancient Greece was not beset by fentanyl and oxycodone. We have a society today in which the fundamental problem for many people has shifted from scarcity and boredom to excess and distraction. Our technology often seems purpose-built to tap into our most basic vulnerabilities. And the question now is how to bring our minds and our bodies and our environments into a more natural balance.

Dhruv Khullar: GLP-1s. They suggest that Aristotle’s moderation is not just a virtue, it is a physiological state. It isn't just about character. It is about biology. And none of this is to suggest that we should somehow give up on the struggle to bring about a more healthful society, that we shouldn't do the hard cultural and political work to bring about a better world in which we can address the drivers of addiction and other social problems, things like loneliness and trauma, pain and poverty, exploitation. But it does suggest that we should welcome a promising new tool into our toolkit.

Dhruv Khullar: Now over the years, I have cared for many patients in the moments when an addiction has taken almost everything from them. The young woman whose post-surgery opioid use turned into a heroin addiction and then into the heart infection that took her life. The father, whose liver failed after decades of alcohol use, who was slowly dying on a transplant list. Every morning I entered his room and was greeted by his children, aged six and eight. And they would ask me when their dad could go home. Those were some of the hardest conversations I have ever had.

Dhruv Khullar: In recent months, I have returned again and again to something that Mary told me. She said that GLP-1s enabled her to act not just on her immediate desire to stop drinking, but on her deeper desire to reinvent the person she wanted to be, to change her habits, her relationships, even how she saw herself. She gained a kind of freedom to live alongside her desires instead of being ruled by them. "Because alcohol was no longer an issue," she told me, "I finally had the chance to think, what type of life do I want?" And that is a question that every person deserves a chance to ask. Thank you. (Applause)