At a conference focused on aging, Novo Nordisk and Eli Lilly shared data suggesting their GLP-1 weight-loss drugs may do more than slim down patients — they may slow how quickly those patients age. Each company showed evidence that people treated with their medications seemed to age more slowly than those who took a placebo.
The proof stems from “aging clocks,” instruments that gauge biological age through alterations to DNA or protein readings. Across repeated trials, the firms discovered that people given GLP-1 medicines displayed a lower biological age than those on placebos. The gap was modest — roughly two to three years — yet steady enough to catch notice from scientists who have devoted years to building these clocks.
What GLP-1 Drugs Actually Are
GLP-1 drugs trigger a receptor in the brain that signals fullness, which cuts hunger and leads to weight loss. Beyond that basic mechanism, though, the drugs appear to offer far more than appetite control alone. Observational evidence shows these medications boost kidney function, lower blood pressure, and dramatically slash the risk of death across the board.
At Aging Research & Drug Discovery, a conference centered on developing scientific cures for old age, the companies shared their findings. No single clear victory has emerged from the quest so far. Yet some researchers believe Novo’s drug semaglutide — sold as Ozempic and Wegovy — is nearing that mark.
The Clocks Tell a Consistent Story
Novo drew blood from 10,052 subjects, dividing them into two groups, one receiving the drug and the other a placebo. Samples were taken at the beginning of MIT Technology Review’s study and again months later, then analyzed with “proteomic clocks” that gauge a person’s age and risk of death through protein levels. Researchers at Eli Lilly conducted parallel work on their GLP-1 medication, tirzepatide, employing “epigenetic” clocks that measure age by tallying accumulated changes to DNA.
“All the clocks are telling a consistent story that we’re seeing a reduction in age,” Kevin Duffin, vice president for aging research at Lilly, said during the conference. “It’s not like we’re going to reverse age by 30 years or something, but it’s a significant reduction.”
The findings did not all point the same way. How much biological time slowed down differed based on the kind of clock being measured and which body part was checked. A single clock registered a slowdown of up to 4 years when it was measuring proteins from the heart.
The Danish drug company Novo employs Alejandro Aguayo-Orozco as a senior scientific director, and he is quoted as saying “I think it’s pretty clear that the organ age is shifting,”.
Why the Clocks Matter
For ten years, the clock makers have been working toward this kind of study, says Yuge Ji, a biologist who formerly worked in the field and now runs a startup called Reflector Bio. The research is a major step forward for the science of aging clocks, which have long reflected a person’s age but were uncertain whether they could be used as true biomarkers.
Clock makers now have proof that their readouts register a decline in age when people use medications with wide-ranging, well-proven advantages.
The Numbers Behind the Drugs
Semaglutide, which is also sold under more than one name, comes from Lilly’s tirzepatide, sold as Mounjaro for diabetes and Zepbound for obesity, topped the list with more than $36 billion in revenue to the company last year. Novo’s semaglutide sits as a close second among the best-selling drugs in the world, where the GLP-1 drugs already dominate.
The revenue figures come from the source’s report, which attributes the sales totals to each company’s GLP-1 offerings.
A Scientist’s Backing
Steve Horvath, a professor at the University of California, Los Angeles, who’s credited with inventing aging clocks, called the emerging data “pretty strong.” He said the findings could provide “evidence that these GLP-1 drugs are actually what is known as geroprotectors, medications that slow or possibly even reverse biologic aging.”
According to Horvath, lowering biological age by two years carries significance in his estimation.
The Question Nobody Wants to Answer
A Harvard biologist who helped Novo with its molecular measurements believes the drugs act as anti-aging treatments in people who are not well. In people who are in good health, though, no one can say for sure.
“I do think it’s an anti-aging drug,” Gladyshev said. “But in a healthy population, no one knows.”
The doubt was plain for all to see when Insilico Medicine founder and Boston meeting organizer Alex Zhavoronkov asked outright if the first mass-market anti-aging remedy is already here. Zhavoronkov has pushed the notion that humanity is moving into a new age of longevity medicines.
“I am on tirzepatide and I am an equal-opportunity injector of semaglutide as well,” Zhavoronkov said.
The host turned to Aguayo-Orozco, the Novo scientist, and asked if a sensible individual ought to begin taking semaglutide.
“I am not a physician. I cannot answer that question,” Aguayo-Orozco replied.
The Side Effects Nobody Wants to Mention
A number of individuals warned that GLP-1 medications carry side effects, among them muscle loss, which is part of why they may fail to extend the lives of most people.
Neither the companies nor the conference presentations have offered full details about the extent of side effects from their GLP-1 drugs. The presentations also avoided answering whether these medications might extend life expectancy beyond what biological aging measures show.
The Verdict
Research indicates that GLP-1 medications lower markers tied to aging at the cellular level. Whether this actually extends lifespan remains unclear. No peer-reviewed papers from the companies have appeared with complete details on the findings.
There is no proof from these companies that the drugs add years to a person’s life. What has been demonstrated instead is that the molecular clocks inside patients taking the drugs show readings that indicate a younger biological age.
Novo Nordisk is counting on semaglutide (Ozempic, Wegovy) to hold its own against Eli Lilly’s tirzepatide (Mounjaro, Zepbound), which brought in more than $36 billion in revenue last year. Novo’s drug is the second-best selling GLP-1 drug, and it is being put to the test in a trial that has enrolled 10,052 people, with half taking the drug and half taking a placebo. The company’s scientists say the drug can slow biological aging by two to three years, as measured by epigenetic clocks, a figure attributed to Novo’s Nikolaj Roed. Another Novo researcher, Aguayo-Orozco, says the drug can slow the heart’s internal clock by up to 4 years. The findings were presented at the Aging Research & Drug Discovery conference.
Key Facts Box
- Trial size: 10,052 subjects, half on the drug, half on placebo
- Semaglutide (Ozempic, Wegovy): Second-best selling GLP-1 drug; more than $36 billion in revenue last year
- Tirzepatide (Mounjaro, Zepbound): Top GLP-1 drug by revenue; also more than $36 billion in revenue last year
- Biological aging reduction: Two to three years, as measured by epigenetic clocks
- Heart clock slowdown: Up to 4 years
Source material: “Weight-loss drugs show signs of slowing biological aging, say drugmakers,” MIT Technology Review.
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