Some of this work is being funded by the Advanced Research Projects Agency for Health (ARPA-H), a U.S. government agency that launched a new longevity initiative in December aimed at finding gold-standard biological-age clocks that could be used in clinical trials that test anti-aging interventions. ARPA-H says it plans to work with several research groups across the country to identify these clocks through clinical trials and AI-driven analyses of existing datasets.
The goal is to help the longevity industry realize its promise of producing therapies that could delay the aging process by finding quicker and more cost-effective ways to test these interventions in people, says Andrew Brack, a molecular biologist who is leading the initiative, known as PROSPR. “We need a biomarker that can serve as a surrogate for natural aging that could tell you that answer in two or three years. That way, we could get more therapeutics, and they would be less expensive to develop and would get to people quicker,” he says.
As part of PROSPR, researchers will test promising clocks to see how well they can predict a person’s health in the future. They will also use the clocks to analyze the anti-aging—what scientists call “geroprotective”—potential of several commonly used drugs that preliminary research suggests could have health span-extending properties, Brack says. ARPA-H has yet to identify the drugs that it will test, but GLP-1 drugs, the immunosuppressant rapamycin, and SGLT2 inhibitors, drugs that are used to treat Type 2 diabetes, are potential candidates, he says.
“Once we’ve done that trial, it’s possible that not only will we have surrogate biomarkers for health span, but we might also identify the first-generation of geroprotective drugs for people,” says Brack, who previously cofounded a longevity biotech and researched aging as a professor at the University of California, San Francisco. “It’s an exciting time for the field.”
Many longevity researchers and companies are devoting funds and attention to building better clocks and figuring out ways to validate them. Norn Group, Borch Jensen’s longevity think tank, is working on developing a testing program that it says could evaluate existing clocks and how accurate and interpretable they are. The Biomarkers of Aging Consortium, a group focused on the creation of proven and standardized biological-age tests, launched a contest in 2024 that pits different clocks against one another. The competition is ongoing.
“Everybody claims their clock is the best, but there’s no fair comparison of them,” says Vadim Gladyshev, a member of the consortium’s scientific steering committee. “We need standard datasets, analysis, and harmonization.”
Gladyshev, a professor of medicine at Harvard who studies aging and whose lab has developed its own clocks, says he is excited about next-generation clocks that could analyze multiple biological processes and patterns instead of just one. Such clocks would likely be more informative and useful, he says.
Clocks that measure aging of specific organs and not just aging of the entire body could also be transformational, Gladyshev says. Research done by his lab and others has suggested that people’s organs may age at different rates. “Maybe the kidney is aging faster than the brain, for example, and in those cases, we might need interventions that are more personalized and that target specific organs,” says Gladyshev.
Wyss-Coray, the Stanford researcher, is a pioneer of organ-specific biological age clocks. His lab has created a blood test that can estimate how well specific organs are functioning by measuring proteins that are unique to them. Vero Bioscience, a company Wyss-Coray cofounded to help commercialize this technology, is now working with private clinics to test the clock at a small scale in real patients.
“We are working closely with clinicians to assess the ages of a person’s organs,” Wyss-Coray says. “Clinicians make recommendations based on the test, and then we follow the patients and collect data.”
Larger studies need to be done to truly validate organ-specific clocks and other tests like it. But Wyss-Coray says he thinks such clocks could be used in clinics in a few short years. “The major hope is that we will be able to do preventative medicine and give people real feedback” about whether treatments and other interventions are working to improve their health, he says. “It could completely change medicine.”