Novo Nordisk and Eli Lilly recently presented early clinical data at the Aging Research & Drug Discovery (ARDD) conference, suggesting that GLP-1 receptor agonists—a class of drugs including semaglutide and tirzepatide—may slow molecular measures of biological aging. These findings represent the first clinical readouts to tie this specific drug class to 'aging clocks,' which are tools used to predict a person's biological age and mortality risk based on protein levels or DNA methylation.
Novo Nordisk reported findings from a study of 10,052 participants, where half received semaglutide and the other half received a placebo. The company utilized 'proteomic clocks,' which track key protein levels, and observed a broad slowdown in aging across various tissues. Specifically, the data showed a difference of roughly two to three years in biological age, with a heart-protein-specific clock showing a shift of up to four years. These proteomic signatures were associated with improvements in vitality and locomotion. In contrast, Eli Lilly presented a smaller epigenetic sub-study within its SURMOUNT-5 trial. This study used 'epigenetic clocks' to measure DNA methylation changes in participants taking tirzepatide. Over a period of 1.38 years, all 15 age-unit clocks showed less aging than the actual time elapsed, with some clocks showing median gains of up to 1.1 years.
This image serves as a conceptual representation of the 'aging clocks'—proteomic and epigenetic tools—discussed in the study of biological age.
Despite these promising signals, the findings are currently framed as preliminary and hypothesis-generating. Eli Lilly noted that the sub-study was small, single-arm (lacking a placebo group), and conducted over a relatively short duration. Furthermore, while the drugs show clear benefits for individuals with obesity or diabetes—such as improved kidney function and reduced blood pressure—scientists remain uncertain about their effects on healthy populations. Some researchers cautioned that the observed 'anti-aging' effects might be a byproduct of weight management and caloric restriction, which are well-established to slow biological aging. Additionally, potential side effects like muscle loss remain a consideration for the long-term use of these medications as longevity treatments. The next phase of research will involve larger, ideally randomized studies to determine if these drugs act as true 'geroprotectors' for the general population.