Semaglutide, the active ingredient in the obesity drug Wegovy, may slow aging itself rather than merely reduce body weight, according to new research. Elderly mice given the drug late in life — at an age equivalent to a human in their 60s — showed gains in muscle strength and memory, and lived about 12% longer.
Mice at a Human Age of 60 Gained 92 Days of Life
According to the study published recently in the journal Nature, an international team including researchers from the University of California, Berkeley and the University of Copenhagen examined the aging-related effects of semaglutide in 20-month-old female mice. Twenty months in a mouse corresponds roughly to a human in their 60s.
The 40 mice given daily semaglutide had a median lifespan of 834 days, compared with 742 days for the 39 control mice given saline — a difference of 92 days, or 12.4%.
Translated directly into human terms, the gap is substantial. Applying a lifespan increase of about 12% to a British woman with a life expectancy of roughly 83 years would add about nine to 10 years. In other words, the difference observed in this animal study, if mechanically converted to humans, would amount to living past 90.
The treated mice did not simply live longer. They moved more actively in unfamiliar spaces and explored their surroundings more aggressively. Physical measures also improved, including balance on a rotating rod, grip strength while hanging from a wire mesh and running endurance. Positive changes were observed in cognitive function as well, including spatial memory.
Aging-related changes inside the body were widespread. Chronic inflammation, cellular senescence, stem cell depletion, genomic instability and declining mitochondrial function all eased. In the dentate gyrus of the hippocampus, a brain region involved in memory and learning, neural stem cell activity and the generation of new neurons increased.
Same Reduced Intake and Weight Loss — Only the Semaglutide Group Differed
The researchers also examined whether these changes stemmed from semaglutide itself or from the mice simply eating less because the drug suppressed their appetite.
In a separate experiment, they compared mice given semaglutide with mice fed 24% fewer calories over five months. The degree of calorie restriction was matched to how much the semaglutide group voluntarily cut its food intake after receiving the drug.
The two groups lost similar amounts of weight and showed similar changes across several physiological measures. But there were differences. In the semaglutide group, exploratory behavior, spatial memory and blood sugar control improved beyond baseline levels, while the calorie-restricted group largely held at baseline.
Metabolic responses also diverged. Oxygen consumption and energy expenditure fell in the calorie-restricted group, while the semaglutide group maintained a normal metabolic rate.
On that basis, the researchers concluded that semaglutide's effects may not come solely from reduced food intake but may act separately on biological processes tied to aging.
Beyond Obesity and Diabetes — A Treatment for Aging?
Semaglutide is a GLP-1 receptor agonist and the active ingredient in Wegovy, an obesity drug, and Ozempic, a diabetes drug. Acting similarly to GLP-1, it stimulates insulin secretion and regulates blood sugar while increasing satiety to suppress appetite.
Research has reported effects of semaglutide across a range of conditions involving the cardiovascular system, kidneys and liver. The researchers focused on the possibility that the aging process underlies how a single drug can affect several different diseases.
Rafael de Cabo, a senior investigator at the U.S. National Institutes of Health, said most chronic diseases are deeply rooted in the aging process, adding that if GLP-1 class drugs genuinely delay aging, multiple health benefits could appear together.
The findings cannot be applied directly to humans, however. The study was conducted in a laboratory on elderly female mice, and humans and mice differ greatly in physiology, lifespan and living conditions. It also remains unconfirmed whether the same effects occur in males, and whether long-term use in humans would actually extend lifespan or healthy lifespan.
