Open this photo in gallery:
Endocrinologist Dr. Daniel Drucker is renowned for his pioneering GLP-1 research.Sammy Kogan/The Globe and Mail
Why are some people “super responders” to GLP-1 drugs, while others barely shed any weight? Should women stop weight-loss therapies if they want to get pregnant, and if so, when? And what are the most pressing safety concerns as millions more people start taking these powerful medicines?
These are just a sample of the dozens of questions raised by a new research priority statement issued by the Endocrine Society, the world’s largest organization of endocrinologists and clinicians who treat hormone-related conditions.
The statement was published in the journal Endocrine Reviews on Wednesday, when the society also launched its Center on Obesity, a new global hub for the latest in obesity science, resources and advocacy.
Led by Daniel Drucker, the Canadian scientist renowned for his pioneering GLP-1 research, a team of eight scientists reviewed more than 200 studies to compile a research roadmap for advancing obesity science in the era of weight-loss drugs such as Wegovy and Zepbound.
Throughout history, transformational discoveries such as penicillin and vaccines have reshaped our understanding of the diseases they aim to treat, the statement said – and obesity drugs are no different.
André Picard: The advent of powerful weight-loss drugs is promising, but not a cure for all that ails us
So the time is ripe for scientists to “seize the moment” with thoughtful research that can chart a path toward improved health, optimized treatments and a better understanding of obesity, the society said.
“There are literally hundreds of questions that are now very germane and very relevant to the clinic that we never even had to worry about before, because we never had medical therapies that could achieve what these medicines do,” Dr. Drucker said in an interview.
“We wanted to put it all together to say, what should the priorities be? And how should we think about this field going forward, beyond the question of just how much weight do I need to lose?”
“We’re now in a position to transform our understanding of obesity.”
Obesity is one of the most “urgent health issues of our time,” affecting one in eight people worldwide, said Amy Rothberg, a University of Michigan professor and chair of the society’s Obesity Strategy Initiative Member Task Force, addressing reporters Wednesday at a virtual press conference.
But in the last few years, GLP-1s have dramatically transformed the treatment landscape. Today, this class of medicines – which include brand names such as Ozempic, Wegovy, Mounjaro and Zepbound – have become Canada’s top-selling drugs, generating about $2.4-billion in sales during the first half of 2026 alone.
Doctors are now prescribing GLP-1 medications not just for diabetes and obesity, but also cardiovascular diseases, obstructive sleep apnea and weight-related liver disease. Researchers around the world are studying these drugs as potential treatments for a growing list of conditions, including Parkinson’s disease, drug addiction and some forms of cancer.
But while GLP-1s have become firmly embedded in popular culture as a weight-loss drug, people should remember that these therapies are still very much in their infancy, Dr. Drucker said. Semaglutide, sold as Ozempic for treating diabetes and as Wegovy for weight loss, was only approved as a weight-loss drug five years ago, he pointed out; tirzepatide (sold as Mounjaro or Zepbound) is even newer.
Scientists are now grappling with urgent research questions that were only theoretical before these drugs came on to the market, he said. The widespread use of GLP-1s is also revealing new phenomena, including the existence of “super responders” – people who lose 25 per cent of their body weight or more on GLP-1s.
Meanwhile, other patients taking the same drug might barely respond to the treatment at all, he said. Scientists didn’t know before about this type of variation between people, “because we never had medicines that would allow us to achieve this kind of weight loss,” Dr. Drucker said.
Opinion: Taking weight-loss drugs could mean spending less on food, but is it worth it?
In the research roadmap, Dr. Drucker and his co-authors identified six broad research questions to better understand: the underlying mechanisms that cause obesity; the variability in types of obesity and treatment responses; identifying treatment targets that go beyond percentage weight loss; fat mass dynamics during the different phases of weight loss induced by obesity drugs; health outcomes for people who take GLP-1s; and the safety of these drugs going forward.
“There are so many things we need to understand about individualized outcomes and how to achieve them,” Dr. Drucker said.
“And there are 100 or more investigational medicines that seek to bring new innovations into the clinic based on these GLP-1 medicines. So we’re going to have these ask all of these questions over and over again, repeatedly.”