Asprey got rich as a young tech mogul in the late 1990s, but he got chronic sinus infections, a terrible skin condition, and an unshakable sense of fatigue. “All the doctors told me I was fine,” he explained. “But I'm a disruptive tech guy, and I was struggling to string sentences together. I realized I was going to have to fire my doctors.”

As a programmer, Asprey was accustomed to hacking his way around trouble, so he decided to solve the problem of his life. He bought his first EEG in 1997 and acquired one of the first commercially available light-therapy machines to, as he says quite seriously, “shine light into my skull and activate the mitochondria.” He studied biology and neurology at his desk every night until he fell asleep. The devotion changed his life, and in the years since, he's become one of biohacking's greatest hype men, spreading the gospel through a massive podcast, a best-selling how-to book, and an annual conference that increases in size every year.

Electrical Brain Stimulation: This therapy relies on a low current of electricity delivered to specific areas of the brain via electrodes. Biohackers argue it boosts cognitive performance. Military scientists think it could become an alternative to prescription drugs like Adderall and modafinil, which are currently used to aid alertness.

The centerpiece of the ever growing empire of biohacker products he sells is Bulletproof Coffee—his own blend of coffee, butter, and concentrated coconut oil that helps enable fasting and adherence to a low-sugar, low-carb ketogenic diet, which he follows and which multitudes of biohackers swear helps improve health and stimulate cognitive function.

Asprey was also an early and very enthusiastic user of nootropics. He's been using the web to hunt them down for so long that he remembers relying on Alta Vista, because Google hadn't been invented. “I've ordered every smart drug that you could buy,” he told me, explaining that modafinil got him through business school at Penn, whereas a drug prescribed to people with Parkinson's that might improve focus “made me depressed.”

The drug he's stuck with the longest is aniracetam, which seems to influence cognitive function without sedative or stimulant effects. “It increases your memory I/O—your ability to get things in and out of your memory,” Asprey said, explaining brain function in the “input/output” parlance of a technologist. He's also a fan of what he calls “nature's two original smart drugs,” caffeine and nicotine. He'll ingest the latter through the low-dose lozenges smokers use to break their habit, though other biohackers cut up transdermal patches and wear the smaller pieces like Band-Aids.

Is the moment finally right for turning biohacking into big business? Maybe the most talked-about newcomer in the race to monetize the movement—and grab a piece of the roughly $21 billion spent annually on supplements in America—is Nootrobox, a start-up founded by Geoff Woo and Michael Brandt. The two Stanford grads began tinkering with supplements in college but quickly realized just how cumbersome and challenging the lifestyle could be for those who wanted to pursue it. Sure, some portion of the movement's appeal may actually derive from its difficulty: There's a certain type of person who enjoys the thrill of sourcing obscure chemicals from Chinese websites and creating his own pills. But Brandt and Woo are betting that there's an even bigger market for people who want to enjoy the benefits of biohacking without having to plumb the web for obscure tips. “This could be mainstream,” Woo said the two decided. “It should be mainstream.”

Parabiosis: Human trials are in their earliest stages, but the theory being tested on mice involves transfusing the blood of younger organisms into older ones to slow aging. Venture capitalist Peter Thiel, who wants to live forever, has reportedly expressed interest in furthering research into the therapy's “rejuvenating effect.”

That's what they're trying to achieve. Having earned early-stage funding from the powerhouse venture firm Andreessen Horowitz—itself a legitimizing vote of confidence—they're marketing a series of simple products that purport to boost clarity, focus, and energy. But it's their Go Cubes that have generated the most hype, beginning in 2016, when they were a sensation at South by Southwest. They're small gummies that contain L-theanine, an amino acid found in green tea, with a half cup of coffee's worth of caffeine in every cube.

Their products sound rudimentary for now and are a far cry from taking LSD in your cubicle. But that's the point, Woo and Brandt say—all the better to make the notion of cognitive enhancement approachable. “You don't have to seem like a freak biohacker,” Brandt said. Think about SXSW: “If we'd been running around handing out little pills, people would have been like, ‘What the fuck?’ ” Instead, everyone was fiending for Go Cubes—and making the case that chewable coffee is a kind of gateway drug to a future full of exotic brain pills.

“In five years,” Woo told me, “nootropics will just be a part of everyone's diet.”

Cryotherapy: A neck-down deep freeze, a.k.a. the longest two to four minutes of your life, sprayed with nitrogen-iced air. We're talking -200 and below. Said to reduce inflammation, stimulate weight loss, and improve sleep. The bargain version is a very cold morning shower or a quick dip into frigid water every day. Photo Illustration by Chelsie Craig

I would like to tell you that after I nervously downed that mug of acid-laced water, I wrote some of the best and most creative prose of my life. But I'm afraid that's not true. The biggest difference I noticed was a significant increase in lucid dreams, and not only on the days when I micro-dosed. I rarely remember dreams, but in the month when I was experimenting with my own brain chemistry, I woke up nearly every day recalling them. In two cases, I remembered dreams in which I was working my way through problems with stories I was writing.

When I actually got down to work, however, the results weren't as obvious. I required less coffee and felt more alert, but that could have been a placebo effect. When you're experimenting with a psychedelic, it's impossible not to constantly wonder.

In fact, a common problem for new experimenters, according to Fadiman, is that people are used to feeling the effects of drugs, and a micro-dose of LSD can sometimes be less perceptible than a cup of coffee. As a result, people increase their dosage until they can feel something—and then they're actually tripping. One guy wrote Fadiman to say that 10 micrograms did nothing, so he tried 25. Then, he reported, “I realized at the sales meeting that I never cared about the stupid product we were selling, so I went home.”

EEG-Based Neurofeedback: By using a device that measures brain waves, biohackers see how their minds are stimulated and then, they claim, learn to retrain them for greater efficiency. Dave Asprey, who wore a headband EEG gadget, says it boosted IQ and was one of the most effective cognitive enhancements he's ever tried.

The trouble, of course, is that the point of a smart drug is to improve cognition, but that's a largely immeasurable concept. “When I first went on smart drugs, I was like, ‘Ah, they don't work!’ ” Dave Asprey told me when I asked about his early experimentation. So Asprey stopped taking them, and he noticed he wasn't as sharp as he had been. What he realized was that he needed to change his expectations—that when the drugs are working, the effect isn't massive; rather, it's “so natural that you feel more like yourself.”