Later this year, 240 mice will begin nibbling food laced with sildenafil citrate, the active ingredient in Viagra. An equal number will start dining on chow that includes the antihypertension drug captopril. The mice don’t suffer from erectile dysfunction or high blood pressure. They are the latest rodent recruits in the Interventions Testing Program (ITP), a 22-year-old project funded and run by the National Institute on Aging (NIA) that gauges whether compounds extend longevity in mice—with the hope that they will also do so in people.
So far, the ITP has evaluated more than 60 drugs, dietary components, hormones, supplement ingredients, and other molecules, alone and in combinations. Sildenafil citrate and captopril are among the eight new candidates announced in late August, a couple of months after NIA announced it would re-up the program’s funding—more than $5 million annually—for another 5 years.
Researchers say the ITP has been worth the money. They laud its transparency, meticulous methods, and commitment to replication—each compound is tested at three sites. “It’s important to have this robust validation” of proposed life-extending drugs, says bioinformatician Mahdi Moqri of Harvard Medical School, who is not involved in the project but is investigating biomarkers of aging.