You’re going to get old no matter what you do; it’s a condition of being human. Still, some experts are beginning to think that aging can be slowed with certain drugs or compounds–if only they can figure out which ones. Now a promising new trial has set its sights on metformin, a drug that millions of Americans already consume.
“There are lots of little things that suggest metformin is a little bit on the edge of magic,” says Dr. Nir Barzilai, director of the Institute for Aging Research at the Albert Einstein College of Medicine and head of the new study, called Targeting Aging With Metformin, or TAME. The popular Type 2 diabetes drug has been available in the U.S. for more than two decades and has proved, over and over again, to help treat and even prevent the disease in at-risk people. Researchers in a years-long study gave metformin to people with prediabetes, a condition marked by elevated blood sugar, and found that those who took it reduced their risk of developing Type 2 diabetes by 31%.
But a growing body of research suggests that metformin may also have positive effects for conditions beyond diabetes. The drug has been linked to a reduction in the risk of cardiovascular disease, several types of cancer and glaucoma. A 2014 study found that people with Type 2 diabetes who took metformin lived longer than healthy people without diabetes who weren’t taking it.
The drug works by controlling blood-sugar levels and making the body respond better to insulin. But along the way, it may also slow down elements of aging itself.
The TAME trial, which is estimated to cost $66 million and will take place at 14 centers across the U.S., hopes to enroll 3,000 people ages 65 to 80 who have or are at risk for cancer, heart disease or dementia. Half will take metformin, and they’ll be tracked for about six years. The goal is to see if taking metformin delays the development of illness and death.
While it may sound straightforward, this study will be, in its way, something of a breakthrough itself. Modern medicine focuses on treating one disease at a time; the fight to cure cancer is separate from that of Alzheimer’s, heart disease and Type 2 diabetes. But each of those diseases are linked by an enormous risk factor: getting older. The TAME trial may answer a more tantalizing question: What if we could target aging itself instead of the individual diseases that stem from it? “When several diseases come together, for me, it’s the aging that plays a role, not the specific disease,” Barzilai says.
Which means the TAME trial could be a turning point in our understanding of longevity. “We’ve created this scenario of long lives, and we’ve achieved exactly what we wanted to achieve, which is life extension,” says S. Jay Olshansky, a professor in the School of Public Health at the University of Illinois at Chicago, who is also involved with the trial. “The price we had to pay for that was the rise of heart disease, cancer, stroke and Alzheimer’s.”
The goal of the trial is not to make people live longer but to extend their span of healthy life. If people could achieve even a slight slowing of the biological clock by taking a drug, “it would have a cascading effect on all fatal and disabling diseases,” Olshansky says. “You’d lower the risk of heart disease, cancer, stroke, Alzheimer’s, osteoporosis, osteoarthritis–the economic effect and the health effects are huge.” In a 2013 study, Olshansky and others predicted how much money the U.S. could save if aging could be slowed by about three years, like making a 60-year-old biologically 57. The estimate: $7 trillion over 50 years.
Aging researchers are also studying different compounds and treatments in animals for ways to slow the clock. Several are promising, but they come with risky side effects. That makes metformin, a drug with a long and strong safety record, the current best bet.
If TAME pans out as the researchers hope, it could speed the development of next-generation drugs. Olshansky, for his part, doesn’t know if metformin will end up being the best drug to slow aging, but he’s confident that someone will find one. “When it happens, it’s going to earn somebody a Nobel Prize,” he says, “because it’s going to be one of the more profound public-health interventions in history.”
This appears in the February 22, 2016 issue of TIME.