A weight-loss drug already taken by millions of people may do more than shed pounds — in aged mice, it appears to slow the biology of aging itself. A study published September 2 in Nature found that semaglutide, the GLP-1 drug sold as Ozempic and Wegovy, extended lifespan and improved muscle, metabolic and cognitive function when given late in life to mice — mimicking, and in some measures exceeding, the effects of calorie restriction, the most reliable life-extension intervention known in lab animals.
The research, led by Danica Chen's lab at UC Berkeley with NIH funding, treated 20-month-old mice — roughly equivalent to older adulthood in humans — with semaglutide. One cohort received the drug for three months and underwent detailed physiological testing; a second cohort was treated for the remainder of their lives to measure survival. Median lifespan in the treated group was extended by roughly 100 days compared with untreated controls.
A single-sex, animal-only study
The study's most important limitation is built into its design: only female mice were used. The researchers have not yet reported whether male mice show the same benefit, and prior aging research has repeatedly found sex-specific responses to metabolic interventions — meaning the results cannot be assumed to apply broadly, even within mice, let alone to men. It is also, fundamentally, an animal study: mouse lifespan biology does not translate one-to-one to humans, and the authors were explicit that the findings should guide further research rather than be read as evidence the same effect would occur in people.
Within those bounds, the physiological findings were notable. Treated mice showed improved muscle strength, better spatial memory and exploratory behavior, and reduced markers of inflammation, alongside enhanced tissue regenerative capacity. Gene-expression analysis showed a broad reduction in molecular hallmarks of aging. Compared directly against calorie-restricted mice, semaglutide-treated animals matched or exceeded some benefits — including blood-sugar control — while maintaining a normal metabolic rate, suggesting the drug may work through a pathway distinct from simple caloric reduction.
If GLP-1 agonists do indeed slow it down, then a wide range of clinical benefits is exactly what you'd expect to see.
— Rafael de Cabo, NIH National Institute on Aging
The authors point to preliminary human data — including secondary findings from the unrelated SLIM LIVER trial — as suggestive but far from conclusive support that GLP-1 drugs affect human aging markers. Dedicated clinical trials measuring aging-related outcomes in people, rather than weight or blood sugar alone, have not been done. Until then, the findings remain a mouse-model result: a plausible biological lead, not a demonstrated anti-aging therapy for humans.
