“It’s not like we’re going to reverse age by 30 years or something.” Kevin Duffin of Eli Lilly said that, and it is the most sober line in a story that otherwise sounds like a big promise.
The promise is this. Novo Nordisk and Lilly, the two biggest makers of GLP-1 weight-loss drugs, told the 13th Aging Research & Drug Discovery conference that patients on their drugs show slower biological ageing, according to Gizmodo on 9 October.
Novo looked at clinical trial data on semaglutide (Ozempic, Wegovy). By MIT Technology Review’s account, the trial involved 10,052 people, split evenly between the drug and a placebo. Blood samples were run through “proteomic clocks”, which estimate age from protein levels. The overall slowdown was about two to three years, said Novo’s Nikolaj Roed, and a clock based on heart proteins showed as much as four.
Lilly used epigenetic clocks, which read chemical changes to DNA, on tirzepatide (Mounjaro, Zepbound). Users again showed slower molecular ageing than controls. I could not find figures for that analysis.
The caveats are as long as the results. The data have not been peer reviewed and were produced by company scientists, not independent ones. Ageing clocks are an early science, and nobody knows how many years on a clock translate into real health. The effect varied widely by clock and organ. And participants were living with obesity or type 2 diabetes.
That last point matters most. Harvard’s Vadim Gladyshev said that in a healthy population, “no one knows”. It is possible that someone with obesity who loses weight simply moves closer to their true biological age, which says little about a healthy 50-year-old hoping to stay young.
Side effects count too. These drugs can cause muscle loss, and MIT Technology Review notes that others, from eyesight to hair and nails, are still being worked out. None of this is medical advice: anyone on these drugs should talk to their doctor.
A firmer test is coming. The US agency ARPA-H is funding a $38 million study in Texas, starting in January, to see whether semaglutide has anti-ageing effects in healthy adults over 60. It will measure cognition, mobility and sensory acuity. That trial, not the clocks, will show whether these are longevity drugs.
On sourcing: the size of Novo’s trial, the exact years and the ARPA-H figure come from MIT Technology Review; Gizmodo confirms the years but gives no participant count. For now there are more questions than answers.
