Steve Aoki, the DJ and heir to the Benihana restaurant chain, appears toward the bottom of the site’s “absolute” ranking, which reflects the 25 competitors with the lowest rate of aging.

The biohacker Ben Greenfield makes the list, too, as does millionaire and longevity science advocate Peter Diamandis. Most of the top 25 names, however, don’t spark immediate recognition, and some are anonymous.

Right now, tech millionaire Bryan Johnson, who is 46 years old, is leading. But 46 is just what competitors describe as Johnson’s “chronological age,” which means, simply, the years that have passed since his birth date.

He has claimed that he eats 70 pounds of vegetables per month, most of it pureed. He receives blood transfusions from his 17-year-old son. He wears a red-light cap that’s supposed to stimulate hair growth. His body fat once fell to a dangerous 3 percent (though it has since bumped up a few percentage points).

Twitter founder Jack Dorsey is renowned for his eccentric wellness habits; he eats one meal a day, meditates for at least two hours daily, and has a penchant for ice baths. For a while, Steve Jobs was a “fruitarian” — as in, only ate fruit.

Such extremes are common among the ultrarich, and particularly the Silicon Valley set, a crowd known for its obsession with making moonshot ideas into reality.

The wealthy indulge in countless health trends of varying dubiousness, whether it’s getting IV drips to reduce hangovers, hyperbaric oxygen therapy, implanting devices in the body to monitor health and live longer, even injecting themselves with young blood (a treatment called parabiosis, which Johnson is receiving). This year alone, Johnson will reportedly spend at least $2 million on reducing his biological age.

Society treats them as idols, geniuses whose savvy has vaulted them into the 0.0001 percent of the wealthiest people on Earth. It’s a small hop from there to believing they’d also be savvier than the rest of us about turning back the clock.

Last year, according to a report from the news and market analysis site Longevity. Technology, more than $5 billion in investments poured into longevity-related companies worldwide, including from some big-name tech founders and investors. Many of these companies are aiming to prolong life by focusing on organ regeneration and gene editing.

The buzzy life extension company Altos Labs, which researches biological reprogramming — a way to reset cells to pliable “pluripotent stem cells” — launched last year with a whopping $3 billion investment, and counts internet billionaire Yuri Milner and, reportedly, Amazon founder Jeff Bezos among its patrons. Bezos was also an investor in the anti-aging startup Unity Biotechnology.

OpenAI founder Sam Altman, meanwhile, recently invested $180 million in Retro Biosciences, a company vying to add a decade to the human lifespan.

Some of the most famous names in the death-defying sector are old: Calico Labs, a longevity-research subsidiary of Alphabet, was launched by then-Google CEO Larry Page in 2013.

Tally Health, a new biotech company co-founded by Harvard scientist David Sinclair — who is something of a celebrity in the longevity community — boasts some Hollywood A-list investors: John Legend, Gwyneth Paltrow, Ashton Kutcher, Pedro Pascal, and Zac Efron.

“It’s not possible to reverse your age,” Stuart Jay Olshansky, an aging expert and professor of epidemiology and biostatistics at the University of Illinois Chicago, tells Vox. “There’s validity to some of the work that’s going on in epigenetics that may be telling us something about the rate of aging. It’s not yet telling us about longevity.”

No two people age in the exact same way. Discrete from chronological age, “biological age” is the attempt to capture the often invisible difference through epigenetic gene expression, the state of someone’s organs, their immune system, and more.

A 40-year-old with a history of heavy drinking and smoking, for example, may have a higher biological age than someone who never drinks or smokes. (In 2018, a Dutch man even complained that he ought to be able to change his legal age to match his biological age.)

Johnson, who made his hundreds of millions after selling a payments platform he developed to eBay in 2013, has become renowned not for what he’s invented, sold, or designed, as is the case for many other Silicon Valley entrepreneurs, but for the unimaginably strict lifestyle he leads.

According to his website and the many interviews he has given, he exerts constant vigilance over the 78 organs of the human body, consistently tracking everything from BMI to brain white matter. Johnson is often described as the “most measured man in human history.”