Semaglutide Slowed an Aging Marker 9% in HIV Trial, Study Finds

Does a weight-loss drug make you age more slowly, or does it just make a number on a lab test move? A new analysis lands squarely on the cautious side of that question — and its lead author is the one insisting on the caution.

Researchers at the University of California San Diego and partner institutions report that semaglutide, the GLP-1 drug sold as Ozempic and Wegovy, slowed several molecular markers of biological aging in adults living with HIV. The work, published in Nature Communications, is a re-analysis of a randomized, double-blind, placebo-controlled trial of 108 adults with HIV-associated lipohypertrophy, a condition involving excess fat around the abdomen. About half received weekly semaglutide injections and the rest placebo, over a 32-week treatment period.

To gauge aging, the team used "epigenetic clocks" — tools that estimate biological age from DNA methylation, chemical marks that switch genes on or off without altering the underlying code. Against placebo, the semaglutide group showed a 9 percent slower pace of aging on the DunedinPACE clock, plus a significant effect on PCGrimAge, a clock tied to all-cause mortality risk and age-related disease. The pattern held across measures linked to inflammation and to blood, brain, heart, kidney, liver, and metabolic health.

That breadth is what caught the researchers' attention, not the size of any single result. What stood out to me was less the size of any single effect than the consistency of the pattern across clocks tied to different organ systems, first author Michael Corley, an associate professor at UC San Diego School of Medicine and the Stein Institute for Research on Aging, told Medical News Today.

People with HIV often age faster biologically even when the virus is well controlled, because of chronic inflammation and immune activation — which is part of why the team picked this group to look for a signal. Semaglutide's known effects offer a plausible mechanism: it calms inflammation and strips visceral fat from around the organs, both considered drivers of accelerated aging.

Here is where the framing matters. The result is a change in biomarkers, not in how long anyone lived or whether they developed disease.

"We are not saying that semaglutide reverses aging or makes people younger. What we are seeing is a signal that it may slow some of the biological processes associated with aging."

Michael Corley, PhD, UC San Diego

A separate, smaller pilot study in npj Aging points the same direction without strengthening it much. Over 24 weeks in people with HIV and fatty liver disease, semaglutide reduced the pace of aging on DunedinPACE in 42 percent of participants, slowed mortality-risk markers on PCGrimAge in 34 percent, and lengthened telomere markers in nearly 49 percent. Encouraging consistency — but a pilot, with small numbers and percentages of responders rather than a population-wide effect.

The limitations are not footnotes. Both studies looked only at people with HIV, so the findings may not carry over to the general population. They measured molecular biomarkers, not clinical outcomes such as lifespan or disease rates. And a post-hoc analysis is built to generate hypotheses, not confirm them.

What would change the picture is a trial designed from the start to test aging, in people without HIV, tracking outcomes that matter to patients rather than methylation alone. Corley said as much: it is reasonable to hypothesize similar effects in people without HIV, but that has to be confirmed in dedicated trials establishing how durable the effect is and what dose and duration it takes. For now, anyone reading this as a reason to start semaglutide for longevity is getting ahead of the evidence — including the evidence its own authors are willing to claim.