At UC San Diego, researchers have just documented something that once seemed purely theoretical: a widely prescribed obesity drug may actually slow the pace at which our cells age. The finding comes from a randomized, placebo-controlled clinical trial of semaglutide, a GLP-1 receptor agonist that has already transformed treatment for diabetes and weight management. But this new evidence, published in Nature Communications, suggests its benefits extend far deeper—into the molecular machinery of aging itself.
The study centered on 108 adults with HIV-associated lipohypertrophy, a condition where excess fat accumulates around the abdomen despite antiretroviral treatment. Half received weekly injections of semaglutide over 32 weeks; the other half received placebo. Researchers then used epigenetic clocks—biological markers that detect chemical changes on DNA called methylation—to track whether treatment slowed or accelerated cellular aging. These clocks measure alterations that regulate how genes switch on and off without changing the genetic code itself, offering a window into biological age separate from chronological years.
The results were striking. Participants treated with semaglutide showed a broad pattern of slower aging across multiple epigenetic clocks linked to inflammation and blood, brain, heart, kidney, liver, and metabolic health. Most compellingly, the drug slowed biological aging by 9% overall, as measured by the DunedinPACE epigenetic clock—a significant deceleration over just eight months. The drug also significantly slowed biological processes associated with all-cause mortality and age-related disease risk, according to the PCGrimAge epigenetic clock.
Michael Corley, the study's first author and an associate professor at UC San Diego School of Medicine, explains that people with HIV often experience accelerated aging even when the virus is well controlled. Semaglutide appears to counter this through multiple pathways: by reducing inflammation and metabolic stress, the drug decreases chronic immune activation—a primary driver of accelerated aging in this population. It also shrinks visceral fat around organs, dampening the inflammatory and metabolic signals that fuel aging.
"Emerging data also suggest that GLP-1 drugs may reprogram certain cells in different organs, which could explain why we see effects across multiple aging clocks," Corley noted. That cellular reprogramming may extend benefits beyond HIV-positive individuals. A related pilot study published in npj Aging found that 24 weeks of semaglutide reduced aging rates in 42% of participants with both HIV and fatty liver disease, with those showing improvement also demonstrating greater reductions in liver fat. Nearly 49% of participants showed longer telomeres—protective DNA caps on chromosomes—while also walking faster after treatment, suggesting improved physical function.
Corley emphasizes that the implications reach beyond HIV. "Many of the biological processes we study in HIV are also central to aging in the general population. Because these processes can emerge earlier or be more pronounced in people with HIV, this community can help us identify interventions that may improve healthspan more broadly." As GLP-1 drugs continue reshaping metabolic medicine, evidence that they may actually slow aging itself opens new frontiers—not just for managing disease, but for extending the healthy years we all share.