Novo says biological age fell two to three years on its GLP-1 drug; Lilly reports similar slowing effect
Novo Nordisk and Eli Lilly say patients on their GLP-1 drugs measured two to three years younger on molecular aging clocks than those on placebo. The size of that drop swings with which clock is used and which organ it reads.
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What happened
- Novo drew blood from 10,052 trial participants, half on its drug and half on placebo, at the start and again months later, and ran it through proteomic clocks that read protein levels.
- Both companies presented the readouts over the weekend at Aging Research & Drug Discovery, a conference devoted to scientific remedies for old age.
- The GLP-1 drugs are now the best-selling medicines in the world, sold as Ozempic and Wegovy from Novo and as Mounjaro and Zepbound from Lilly.
Why it matters
- What doesn't add up contradiction Novo's own measurement collaborator, Vadim Gladyshev, calls the drugs anti-aging in sick patients but says no one knows the effect in healthy people, so the longevity reading rests on a group these trials never enrolled.
- What's now possible capability Aging-clock makers get the validation they had lacked: evidence that their readouts drop in response to a treatment, not merely track the passage of time.
- What it sets up precedent If Horvath's reading that these are geroprotectors holds up, two medicines already approved for diabetes and obesity become the leading candidate longevity drugs.
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The clocks predict a person's age from DNA changes or from levels of key proteins in the blood, and both companies say that prediction dropped for patients on the drug [2][1]. The number that moved is a prediction of age, built from a model. Whether a longer or healthier life follows is a separate question these trials did not measure.
Novo put the overall figure at two to three years, according to Nikolaj Roed, a global project leader at the company [3]. One of its clocks, reading heart proteins, moved as much as four years [4]. "I think it's pretty clear that the organ age is shifting," said Alejandro Aguayo-Orozco, a senior scientific director at Novo [5].
The two companies used different instruments and landed in the same place. Lilly ran a smaller study of its drug tirzepatide on epigenetic clocks, which count accumulated DNA changes, and found molecular time slowed for most patients [6]. "All the clocks are telling a consistent story that we're seeing a reduction in age," said Kevin Duffin, Lilly's vice president for aging research [7]. "It's not like we're going to reverse age by 30 years or something, but it's a significant reduction" [8].
Every patient in these trials was overweight or diabetic [1], and in that group the drugs already carry a long file of benefits: they improve kidney function, lower blood pressure, and cut the overall chance of death [11]. A clock that drops in sick patients may be tracking the disease as it recedes. The pace of aging underneath it is a separate thing the trial cannot isolate. Before reading that drop as a longevity result, the question to settle is which of the two the clock followed, and in an overweight, diabetic population the trials were not built to pull them apart.
What to watch
- Whether either company runs the clocks in a healthy, non-diabetic population, where Gladyshev says the effect is unknown.
- Whether regulators accept aging-clock readouts as endpoints, which would let the drugs be studied as longevity treatments.
- Whether follow-up work links the clock movement to hard outcomes like deaths or disease onset, not the biomarker alone.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence45
- Adoption60
- Hype gap+35
- Incentives80
- Confidence50
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Both companies found overweight or diabetic patients taking the GLP-1 drugs had reduced biological age compared with those on placebo, although the difference varied widely depending on which type of clock was used and what organ was tested.
- [2]
Aging clocks assess biological age by looking at DNA changes that accumulate with time, or, in newer versions, by tracking levels of key proteins to predict a person's age.
- [3]
The overall difference was around two to three years, according to Nikolaj Roed, a global project leader at Novo Nordisk.
- [4]
Novo found that over time the drugs cause a slowdown in aging clocks of as much as four years in the case of a clock that looks at heart proteins.
- [5]
"I think it's pretty clear that the organ age is shifting."
- [6]
Eli Lilly performed similar research on its GLP-1 drug tirzepatide using epigenetic clocks that assess age by counting accumulated DNA changes; the study was smaller but also found molecular time moved more slowly for most people on the drug.
- [7]
"All the clocks are telling a consistent story that we're seeing a reduction in age."
- [8]
"It's not like we're going to reverse age by 30 years or something, but it's a significant reduction."
- [9]
It had been uncertain whether aging clocks are useful as true biomarkers; the drug studies now give clock makers evidence that their readouts show a drop in age when people take drugs with broad, well-demonstrated benefits.
- [10]
Steve Horvath said the emerging data could provide evidence that GLP-1 drugs are geroprotectors, "medications that slow or possibly even reverse biologic aging."
- [11]
The drugs cause weight loss by stimulating a GLP-1 receptor that tells the brain you are not hungry, and real-world studies have shown they improve kidney function, reduce blood pressure, and sharply cut the overall chance of death.
- [12]
"In an unhealthy population, I do think it's an anti-aging drug. But in a healthy population, no one knows."
- [13]
As part of its study Novo took blood draws from 10,052 people, half on the drug and half on placebo, collected at the start of the study and again months later, and measured them with proteomic clocks that use levels of key proteins to predict a person's age and risk of dying.
- [14]
The companies shared their findings over the weekend during Aging Research & Drug Discovery, a conference devoted to seeking scientific remedies for old age.
- [15]
The GLP-1 molecules have become the best-selling drugs in the world; Novo's semaglutide is sold as Ozempic and Wegovy, and Lilly's tirzepatide as Mounjaro for diabetes and Zepbound for obesity.
Sources
2 independent publishers whose own reporting we read for this story.
- gizmodo.comYour Ozempic Prescription May Come With a Surprising Bonus: Slower Aging
1 article · October 9, 2026
- technologyreview.comWeight-loss drugs show signs of slowing biological aging, say drugmakers
2 articles · October 9, 2026
Topics and entities
Topics
- Longevity medicine
- GLP-1 drugs
- Aging clocks and biological age scores
Entities
- Eli Lilly
- Semaglutide
- Tirzepatide
- Aging Research & Drug Discovery
- Insilico Medicine
- Novo Nordisk