Old age is, we know, a gauntlet of chronic illness that almost no one gets through without some deep unpleasantness. Most people who reach the upper end of the average human lifespan begin, at some point, to accumulate diseases. For the most lethal maladies of the elderly — heart disease and cancer — the relationship between age and disease is logarithmic. As we grow older, our risk of contracting a chronic disease doesn’t just increase—it accelerates.

Michael Cantor would like to avoid this fate. He’s not a fanatic—not the type to haunt biohacking subreddits for self-quantification tips or take dozens of unproven anti-aging treatments in the off chance one will buy him some yardage. Cantor is a patent lawyer with a prominent practice in West Hartford, Connecticut, where his wife is the mayor. “I don’t even like to take aspirin,” he says. “I’m very nervous to do anything with respect to any other kinds of drugs.” But still, if there were a reasonable way to stave off death — he’d like to try it.

A decade ago, on a cycling trip in Bordeaux, Cantor met a man named Nir Barzilai, and the two became friends. A former Israeli army medic, now director of the Institute for Aging Research at the Albert Einstein College of Medicine in New York, Barzilai has become a globetrotting evangelist for what is known as the “geroscience hypothesis”: the idea that if you use drugs to target the underlying biological mechanisms that drive aging, you can also delay, or even altogether prevent, the cascade of disease that accompanies the end of the typical human life.

For the past several years, an effort has been underway in the field of gerontology to get a drug targeting aging approved by the FDA, with Barzilai leading the charge. The drug in question is no new wonder pill, but a diabetes medication called metformin: an ordinary, generic, typically chalky-white pill that costs a few pennies apiece.

Cantor was already familiar with metformin, but not as an anti-aging remedy; he had been prescribed it by a local weight-loss clinic. A few years ago, intrigued by his friend’s work on aging, he broached the subject of longevity.

Metformin, Barzilai and his team believe, will be the first drug ever to be officially approved to treat aging.

“Over dinner one night, I said to Nir, ‘You know, I’m leaving this weight-loss clinic, which means they’re going to stop prescribing metformin. But I think I’d like to stay on it,’” Cantor says. Barzilai wrote the prescription himself, and Cantor now takes metformin off-label in hopes that it will grant him a few extra years of life, or at least of health.

“I’ve bought into this idea — it’s not just an idea, it’s a fact — that you don’t really die of old age,” Cantor says. “Most people die of age-related disease.”

Although metformin’s age-extending powers are unproven, Cantor doesn’t mind being a guinea pig. He thinks the drug is subtly improving his health. “My experience is only positive,” he says. “It’s changed my metabolism.”

In the world of anti-aging research, there are any number of exciting potions in the pharmaceutical pipeline with the purported potential to extend the average human lifespan by several years or more. There are senolytics, which act like snipers, snuffing out old cells that have stopped dividing and have begun to secrete destructive inflammatory cytokines. Rapamycin, an immunosuppressant derived from an Easter Island bacterium that has lab mice living 25 percent longer than their unmedicated peers.

Metformin, by contrast, is decidedly unsexy. Currently the eighth most-prescribed drug in the United States, metformin has been plodding along in the medical world since the 1950s, when French doctors began using it to help diabetics keep their blood sugar under control. Scientists are now looking at it in a new light, ever since diabetes researchers observed that it appears to extend the lifespan of medicated patients slightly beyond that of ordinary nondiabetics—just enough to notice an effect, but nothing radical.

“Metformin is basically the first and the weakest drug that will delay aging.”

Soon, Barzilai and a team of gerontologists from 14 top aging research centers will begin a clinical trial to study the effects of metformin on aging. The trial will be an ambitious six-year, $77 million effort, involving 3,000 patients and many of the brightest lights in the field of gerontology. Metformin, Barzilai and his team believe, will be the first drug ever to be officially approved to treat aging in the 112-year history of the FDA. Along the way, they hope to achieve nothing short of radical transformation in the way we think of health care for the aging.