Canadian scientist wins Breakthrough Prize for discovery of hormone used in Ozempic, Mounjaro

A Canadian researcher has won a 2025 Breakthrough Prize in Life Sciences for discovering the GLP-1 hormone used in diabetes and obesity medications — including Ozempic, Wegovy and Mounjaro — that have changed the lives of millions of people around the world.

Dr. Daniel Drucker, an endocrinologist and a clinician-scientist at the University of Toronto and the Lunenfeld-Tanenbaum Research Institute at Sinai Health, shares the $3 million US prize with four colleagues from the United States and Denmark.

They were all involved in the development of the now-famous drugs manufactured by Novo Nordisk and Eli Lilly. Drucker and three co-winners made discoveries about glucagon-like peptide-1 in their labs. The other recipient of the award, Lotte Bjerre Knudsen, who works for Novo Nordisk, led the way in developing it into medications.

The Breakthrough Prizes, often referred to as the "Oscars of Science," were handed out Saturday in Los An​geles for categories including fundamental physics and mathematics, in addition to life sciences.

The Breakthrough Foundation says the prizes were created to "celebrate the wonders of our scientific age." Another Canadian, Maaike van Kooten of National Research Council Canada, shared a $100,000 US prize called New Horizons in Physics with two international colleagues for work in optics to view exoplanets.

In an interview in the week prior to the event, Drucker said the prize is meaningful because it's awarded by other scientists and "gets a lot of attention in the scientific community."

"We have students and trainees and awards like this tell them that the world is watching and thinks the work is meritorious. And I think that's just great for morale and for young people," he said.

Drucker began his journey studying genetic sequencing of glucagon-like peptides at a lab in Boston in the 1980s, then returned to Canada and continued his work at the University of Toronto.

He spoke with The Canadian Press about those early days, what he thinks about how the resulting medications have changed the world's view of obesity and what other health issues GLP-1 might address in the future.

This interview has been edited for length and clarity.

When you started at that lab in Boston, why were you studying this particular hormone?

"There were probably about a dozen projects in the lab at that time. So some people were working on pituitary hormones. Some people were on basic cell biology projects. Other people were working on different genes and glucagon was one of the projects in the lab.... It just so happened when I got there, they said, 'OK Drucker, you work on the glucagon gene.' [It] could have been another gene [and] you never would have heard from me again.

Were there any key moments where you thought, 'Wow, this is a big deal?'

"I don't think there was any one 'Eureka!' moment, but I will say the potential importance dawned on me when I walked into the lab one day and my notebooks were gone. And I said, 'Oh my gosh, someone broke into the lab and stole my notebooks.' And then it turned out no — my supervisor [and a fellow prize winner], Joel Habener, took my notebooks because he was excited enough about the results to file a patent."

When did you come to the University of Toronto?

"I came back in 1987.... In 1996, when we and others discovered that GLP-1 inhibits food intake, that was in my lab in Toronto, and we've done experiments on heart disease and inflammation and kidney disease and liver disease. So I literally have been working on this for 40 years."

When did Novo Nordisk (manufacturer of Ozempic and Wegovy) become involved?

"I think the big companies, Novo Nordisk and Eli Lilly, and even other companies were trying from the beginning to develop medicines based on GLP-1. But we learned through some painful lessons that if you give too much GLP-1 too quickly, people throw up. It's still a side effect today, right? Some people just don't feel well and they have some nausea and vomiting. And so it took the pharmaceutical industry quite a while to figure out how to make GLP-1 last longer so it's not broken down, how to give small amounts to start off with, how to slowly build up the dose, et cetera. And that took years to do."

What are you working on now and what are some other applications for GLP-1 drugs?

"If we just look in the last couple of years, beyond lowering blood sugar and beyond reducing body weight, we have seen that these medicines reduce the rates of heart attacks and strokes and reduce the rates of diabetic kidney disease and are helpful for people with obstructive sleep apnea and reduce disability in people with arthritis and prevent the development of severe metabolic liver disease. And there are trials underway in Parkinson's disease, in Alzheimer's disease, in substance use disorders.

"So I kind of look at this and I go, 'Wow, how does that happen? What are the things that GLP-1 is doing in the brain or in the blood vessels or in the kidney to improve the health of these organs?' So we're really focused on this aspect of GLP-1, including how GLP-1 reduces inflammation, which we think is a major part of the benefits that GLP-1 brings to the table."

Are cardiovascular benefits because GLP-1 medication reduces weight or manages diabetes and that improves cardiovascular health?

"What we're starting to see is that in many of the trials, the benefits don't strictly correlate with weight loss or blood sugar control. So there's no question [that] getting your blood sugar normal if you have Type 2 diabetes, reducing your body weight if it's too high, that's helpful.

"But when we actually look at the trials and we see who has the benefit and who doesn't, there's not a perfect correlation with blood sugar control or weight loss. And so we think there are, you know, independent actions of GLP-1, perhaps through reduction of inflammation, that are also beneficial. And this is exactly what we try and study in the lab."

We're now seeing a culture shift in how we view obesity. What do you make of that?

"It's a very complex discussion. So let's say 10 years ago, we had a very understandable movement, which was 'healthy at any size.' Don't focus on your weight per se, focus on your health, which I still think is a very powerful message. And part of that messaging was because we didn't have solutions other than bariatric surgery to allow people to become healthier, perhaps at a lower body weight.... And in society, there tends to be a segment of our society that looks at people living with obesity and says, 'Well, you know, it's just willpower. If you really wanted to lose weight, you could, you're just not trying' or 'You're lazy,' or you know, 'You're weak.'

"And we know that many of these people that we see in clinical practice have been on very calorie-reduced diets and working out and doing everything that we asked them to do. But their brains are defending a higher body weight.... And now with the GLP-1 medicines, we see that... we can help people lose weight. And I think this is very powerful because the people who were struggling before who could not do it by themselves can now lose 10, 15, 20, 30, 50 pounds."

Do you have any trepidation or thoughts about these drugs being used by people who may not need them?

"Well, you're speaking to the person who worries about everything, so of course I have concerns... It's been a little bit like The Hunger Games. People have to phone six pharmacies and find one that had a month's worth of drugs and then drive as fast as they could to that drugstore to get them, which is not great. And so while that's happening, to see other people getting a prescription because Uncle Harry's wedding is coming up in two months and they just want to lose a little bit of weight so they can look a little more fit at Uncle Harry's wedding — you know, as a physician, I say, 'Wait a sec, this person living with heart disease and Type 2 diabetes needs these medicines to reduce the risk of heart attacks and strokes. Maybe that should be a priority as a society over you looking a little better for Uncle Harry's wedding.' So that's been one dilemma.

"And then the other big challenge that we still have is these medicines are very expensive. In many jurisdictions, we don't have everyone with access to a drug plan. We don't [have] every drug plan agreeing to reimburse for the medicines.

"And finally... we don't have clinical trials on healthier people without diabetes, without a higher body weight that are studied [to know], 'Well, are there any particular side effects in this group of individuals?' They weren't studied in the clinical trials. Is there something we should be worried about, going on and off the drugs when you want to lose weight...is that healthy? We don't know. And so we have to always be mindful of what we don't know about the safety of these medicines."