Drugmakers say GLP-1 treatments show signs of slowing biological aging

The Big Picture

Popular GLP-1 medicines may do more than help patients lose weight, according to new findings reported by drugmakers Novo Nordisk and Eli Lilly. The companies said patients taking their drugs showed lower readings on molecular measures known as biological aging clocks than patients who received placebos.

The results were presented over the weekend at the Aging Research & Drug Discovery conference and reported by MIT Technology Review on Oct. 6. They have fueled interest in whether the medicines could be considered geroprotectors, treatments that slow or possibly reverse aspects of biological aging. But the evidence remains preliminary, varies by the type of clock used, and does not establish that the drugs extend human life or reverse aging in healthy people.

What Happened

Novo studied semaglutide, sold under the Ozempic and Wegovy brands, using proteomic clocks. Those tools use levels of key proteins in blood to estimate biological age and risk of death. The company analyzed blood samples from 10,052 people, with half receiving the drug and half receiving a placebo.

Nikolaj Roed, a global project leader at Novo, said the overall difference in biological-age readings was about two to three years. The result depended substantially on the clock being used and the organ or tissue under examination. Novo said one clock focused on heart proteins showed a slowdown of as much as four years.

Eli Lilly conducted similar research involving tirzepatide, which is sold as Mounjaro for diabetes and Zepbound for obesity. Lilly used epigenetic clocks, which estimate age through accumulated changes to DNA. Its study was smaller than Novo's, but Lilly said molecular aging generally moved more slowly among people receiving tirzepatide.

Kevin Duffin, Lilly's vice president for aging research, said at the conference that the clocks consistently showed a reduction in age. He cautioned that the findings did not mean the medicine would reverse age by decades.

Why It Matters

GLP-1 drugs stimulate a receptor that signals satiety to the brain, helping people eat less and lose weight. Their benefits may reach beyond weight reduction. MIT Technology Review reported that real-world studies have associated the medicines with improved kidney function, lower blood pressure and a lower overall risk of death.

The new company results are also notable for the field of aging clocks. Researchers have long debated whether these molecular measurements are useful biomarkers of changes that matter for health. A lower clock reading after treatment with medicines that have already demonstrated broad health benefits could support their value as a way to study potential longevity therapies.

Steve Horvath, a University of California, Los Angeles professor credited with inventing aging clocks, said a two-year effect would be strong. He said the emerging data could support the view that GLP-1 drugs are geroprotectors.

What Each Side Is Saying

Vadim Gladyshev, a Harvard biologist who assisted Novo with molecular measurements, said semaglutide could be considered an anti-aging drug in an unhealthy population. But he said no one knows what its effects would be in healthy people.

Alejandro Aguayo-Orozco, a senior scientific director at Novo, said semaglutide is known to affect several diseases relevant to health span and aging. Novo's data, he said, indicate that treatment moves molecular aging clocks.

Researchers also urged caution. GLP-1 medicines can have side effects, including muscle loss, and Horvath said that concern is one reason he was not ready to take the drugs himself. During the conference, when asked whether a reasonable person should start taking semaglutide, Aguayo-Orozco said he was not a physician and could not answer the question.

What Happens Next

The findings point to questions that will require further study: whether clock changes translate into longer or healthier lives, whether the effects occur in people without obesity or diabetes, and how any potential aging benefit should be weighed against side effects. For now, the results show an association in company research, not proof that GLP-1 medicines are general anti-aging treatments.