In early 1954, Pope Pius XII summoned a venerable Swiss quack named Paul Niehans to the papal retreat at Castel Gandolfo. The pontiff was nauseated with gastritis, fatigued by his 77 years, and loath to meet his maker. So he had Niehans administer an anti­aging treatment called cell therapy, which would become sought after by midcentury celebrities, artists, and politicians.

Fetal cells were taken from a pregnant sheep and injected into the scrawny pope. Over time, Pius received a series of shots. The Holy Patient felt rejuvenated; Niehans was appointed to the Pontifical Academy of Sciences in thanks. But if the treatments worked at all, it wasn’t for long: Pius died four years later.

Niehans’ Clinique La Prairie is still in business, charging tens of thousands of dollars for its weeklong “revitalization program.” But today the death-­phobic elite demand more scientifically sound approaches. Investor Peter Thiel is reportedly “really interested” in the blood of the young. Based on an old idea called parabiosis, the therapy excited new enthusiasm after a 2013 paper showed that a protein richly abundant in young blood made old mice stronger. For $8,000, a company named Ambrosia will now infuse older patients with the blood serum of donors aged 16 to 25.

All over Silicon Valley and the regions that imitate it, executives follow weird revitalization fads. They think the code of aging can be hacked and death made optional. Daniel Gross, a partner at Y Combinator, fasts enthusiastically—and encourages others to do so—because he believes it will extend his life. Inventor Ray Kurzweil swallows 100 supplements a day for the same reason, presumably so he’ll live long enough to be uploaded into the singularity, circa 2045.

But you don’t have to be a prophet of posthumanism to wish for a few more good years. I’ve followed my own antiaging routines: For a time I ate 30 percent fewer calories than recommended, and I now starve myself for 16 of every 24 hours. And while there’s certainly plenty of folly in the tech elite’s quest for immortality, I’m glad they’ve embarked on it—for reasons that go beyond sheer entertainment value.

Unhappily for me—and everyone else—we’ve made little progress in extending the outer limit of the human lifespan. Yes, more people are living longer because we’ve gotten better at nutrition, curing acute conditions such as infections, and treating a handful of chronic diseases. But the maximum reported age at death has plateaued at around 115 years.

What’s tantalizing, however, are the breakthroughs in extending the healthy lifespan of other species. Two decades ago, UC San Francisco researcher Cynthia Kenyon showed that a mutation in a single gene can allow a roundworm to live twice as long. And at MIT, biologists Leonard Guarente and David Sinclair discovered that a class of genes called sirtuins regulates longevity in a wide range of organisms. Restricting the calories of yeast made them overexpress a particular sirtuin, extending their life­spans; mice genetically altered to overproduce the mammalian version lived longer and had fewer age-related diseases.

But for all those animal discoveries, human aging is a problem that the biomedical industry and its regulatory agencies are ill-suited to solve. It’s not a disease recognized by the FDA, and testing drugs for human life extension would be costly and time-­consuming. As Sinclair says, “The aging field is thriving scientifically. But the translation of findings into treatments is poorly funded. Compared to heart disease and diabetes, the dollars allocated to aging are, at best, a hundred to one. But all it will take is one success to change the way people think.”

We'd still die when we do now, but we'll be healthier while we're still living.

So far, the search for that first big success is stuck in the weeds. Elixir Pharmaceuticals, a company cofounded by Kenyon and Guarente to develop therapies that target aging, failed to create such a drug. Sirtris, founded by Sinclair, was equally unsuccessful. And while restricting calories is the best way we know to extend lifespans in organisms from yeast to mice, attempts to create medicines that harness the genes activated by caloric restriction have failed FDA approval.