The promise of a leagues-more-affordable technology that anyone can wear and walk around with is, well, mind-bending. 

This helmet measures changes in blood oxygenation levels.

Over the next few weeks, a company called Kernel will begin sending dozens of customers across the U.S. a $50,000 helmet that can, crudely speaking, read their mind. Weighing a couple of pounds each, the helmets contain nests of sensors and other electronics that measure and analyze a brain’s electrical impulses and blood flow at the speed of thought, providing a window into how the organ responds to the world. The basic technology has been around for years, but it’s usually found in room-size machines that can cost millions of dollars and require patients to sit still in a clinical setting.

The promise of a leagues-more-affordable technology that anyone can wear and walk around with is, well, mind-bending. Excited researchers anticipate using the helmets to gain insight into brain aging, mental disorders, concussions, strokes, and the mechanics behind previously metaphysical experiences such as meditation and psychedelic trips. “To make progress on all the fronts that we need to as a society, we have to bring the brain online,” says Bryan Johnson, who’s spent more than five years and raised about $110 million-half of it his own money-to develop the helmets.


Johnson with one of his helmets in a lab at Kernel’s offices.

Johnson is the chief executive officer of Kernel, a startup that’s trying to build and sell thousands, or even millions, of lightweight, relatively inexpensive helmets that have the oomph and precision needed for what neuroscientists, computer scientists, and electrical engineers have been trying to do for years: peer through the human skull outside of university or government labs. In what must be some kind of record for rejection, 228 investors passed on Johnson’s sales pitch, and the CEO, who made a fortune from his previous company in the payments industry, almost zeroed out his bank account last year to keep Kernel running. “We were two weeks away from missing payroll,” he says. Although Kernel’s tech still has much to prove, successful demonstrations, conducted shortly before Covid-19 spilled across the globe, convinced some of Johnson’s doubters that he has a shot at fulfilling his ambitions.

A core element of Johnson’s pitch is “Know thyself,” a phrase that harks back to ancient Greece, underscoring how little we’ve learned about our head since Plato. Scientists have built all manner of tests and machines to measure our heart, blood, and even DNA, but brain tests remain rare and expensive, sharply limiting our data on the organ that most defines us. “If you went to a cardiologist and they asked you how your heart feels, you would think they are crazy,” Johnson says. “You would ask them to measure your blood pressure and your cholesterol and all of that.”

The first Kernel helmets are headed to brain research institutions and, perhaps less nobly, companies that want to harness insights about how people think to shape their products. (Christof Koch, chief scientist at the Allen Institute for Brain Science in Seattle, calls Kernel’s devices “revolutionary.”) By 2030, Johnson says, he wants to bring down the price to the smartphone range and put a helmet in every American household-which starts to sound as if he’s pitching a panacea. The helmets, he says, will allow people to finally take their mental health seriously, to get along better, to examine the mental effects of the pandemic and even the root causes of American political polarization. If the Biden administration wanted to fund such research, Johnson says, he’d be more than happy to sell the feds a million helmets and get started: “Let’s do the largest brain study in history and try to unify ourselves and get back to a steady state.”

Johnson is something of a measurement obsessive. He’s at the forefront of what’s known as the quantified-self movement. Just about every cell in his body has been repeatedly analyzed and attended to by a team of doctors, and their tests now cast him as a full decade younger than his 43 years. Along those lines, he wants to let everyone else analyze, modify, and perfect their minds. No one knows what the results will be, or even if this is a good idea, but Johnson has taken it upon himself to find out.


After selling his payments startup, Johnson radically changed his life.

Unlike many of his tech-millionaire peers, Johnson grew up relatively poor. Born in 1977, he was raised in Springville, Utah, the third of five children. “We had very little and lived a very simple life,” says his mother, Ellen Huff. A devout Mormon, she stayed home with the kids as much as possible and earned a modest income from a rental unit on the other side of the family’s duplex.

Johnson remembers his mother knitting his clothes and grinding wholesale batches of wheat to make bread. “We were not like my friends,” he says. “They would buy things from stores, and we just did not do that.” His dad, a trash collector turned lawyer, had a drug problem and an affair, which led to his divorce from Huff. Later, delinquent child support payments, missed pickups on the weekends, and legal troubles contributed to his disbarment. “After some time of challenge, my father successfully overhauled his life 20 years ago,” Johnson says. “Throughout his struggles, we remained close and without conflict. He has been a unique source of wisdom, counsel, and stability in my life.”

Johnson had little idea what to do with his life until he served a two-year church mission in Ecuador, where he interacted with people living in huts with dirt floors and walls made of mud and hay. “When I came back, the only thing I cared about was how to do the most good for the most people,” he says. “Since I didn’t have any skills, I decided to become an entrepreneur.”

While at Brigham Young University, he started his own business selling cellphones and service plans, making enough money to hire a team of salespeople. After that, he invested in a real estate development company that collapsed and left him $250,000 in debt. To get out of the hole, he took a job selling credit card processing services to small businesses door to door. Soon he was the company’s top salesman.

This was the mid-2000s, and Johnson’s customers kept complaining about the hassle of setting up and maintaining credit card payment systems on their websites. In 2007 he started Braintree, a software company focused on easing the process with slick interfaces. It succeeded-and had good timing. After signing up a slew of restaurants, retailers, and other small businesses, Braintree became the middleman of choice for a profusion of startups premised on ordering services online, including Airbnb, OpenTable, and Uber. The company also made a great bet on mobile payments, acquiring Venmo for only $26 million in 2012. The next year, EBay bought Braintree for $800 million in cash, a little less than half of which went to Johnson.

Despite his newfound fortune, Johnson felt miserable. He was stressed out and overweight. He’d gotten married and had kids at a young age, but his marriage was falling apart, and he was questioning his life, religion, and identity. He says he entered a deep depressive spiral that included suicidal thoughts.

The decision to sell Braintree well before it peaked in value had been motivated in part by Johnson’s need to change those patterns. “Once I had money, it was the first time in my life that I could eliminate all permission structures,” he says. “I could do whatever I wanted.” He broke with the Mormon church, got divorced, and moved from Chicago, where Braintree was headquartered, to Los Angeles to start over.

Arriving in California, Johnson consulted with all manner of doctors and mental health specialists. His bodily health improved with huge changes to his diet, exercise, and sleep routines. His mind proved a tougher puzzle. He meditated and studied cognitive science, particularly the ways people develop biases, in an effort to train himself to think more rationally. By late 2014 he was convinced his wealth would be best spent advancing humanity’s understanding of the brain. He took a large portion of his windfall and started OS Fund, a venture firm that has invested in several artificial intelligence and biotech companies. These include Ginkgo Bioworks, Pivot Bio, Synthego, and Vicarious, some of the most promising startups trying to manipulate DNA and other molecules.

Mostly, though, Johnson staked his fortune on Kernel. When he founded the company, in 2015, his plan was to develop surgical implants that could send information back and forth between humans and computers, the way Keanu Reeves downloads kung fu into his brain in The Matrix. (In the early days, Johnson discussed a potential partnership with Elon Musk, whose company Neuralink Corp. has put implants in pigs and monkeys, but nothing came of it.) The idea was, in part, to transfer thoughts and feelings directly from one consciousness to another, to convey emotions and ideas to other people more richly than human language allows.

Perhaps more important, Johnson reckoned, AI technology was getting so powerful that for human intelligence to remain relevant, the brain’s processing power would need to keep pace.

Johnson and I began discussing brains in mid-2018, when I was working on a story about the overlap between neuroscience and AI software. During an initial interview at his company’s headquarters in L.A.’s Venice neighborhood, Johnson was cordial but somewhat vague about his aims. But at the end of the visit, I happened to mention the time I underwent a mental healing ritual that involved a Chilean shaman burning holes in my arm and pouring poisonous frog secretions into the wounds. (I do mention this a lot.) Excited, Johnson replied that he had a personal shaman in Mexico and doctors in California who guided him on drug-induced mind journeys. Based on this common ground, he decided to tell me more about Kernel’s work and his own adventurous health practices.

By then, Johnson had abandoned neural implants in favor of helmets. The technology needed to make implants work is difficult to perfect-among other things, the human body tends to muddy the devices’ signals over time, or to reject them outright-and the surgery seemed unlikely to go mainstream. With the helmets, the basic principle remained the same: put tiny electrodes and sensors as close as possible to someone’s neurons, then use the electrodes to detect when neurons fire and relay that information to a computer. Watch enough of these neurons fire in enough people, and we may well begin to solve the mysteries of the brain’s fine mechanics and how ideas and memories form.


A wider shot of the Flux helmet’s enclosure at Kernel’s lab. The booth shields against electromagnetic interference so the instrument can measure very sensitive brain output.

On and off for almost three years, I’ve watched as Kernel has brought its helmets into reality. During an early visit to the company’s two-story headquarters in a residential part of Venice, I saw that Johnson’s team had converted the garage into an optics lab full of mirrors and high-end lasers. Near the entryway sat a shed-size metallic cube designed to shield its contents from electromagnetic interference. On the second floor, dozens of the world’s top neuroscientists, computer scientists, and materials experts were tinkering with early versions of the helmets alongside piles of other electrical instruments. At that point the helmets looked less like 21st century gadgets and more like something a medieval knight might wear into battle, if he had access to wires and duct tape.

Despite the caliber of his team, Johnson and his odd devices were considered toys by outsiders. “The usual Silicon Valley people and investors would not even talk to us or poke around at all,” he says. “It became clear that we would have to spend the time, and I would have to spend the money, to show people something and demonstrate it working.”

A hospital or research center will typically employ a range of instruments to analyze brains. The list is a smorgasbord of acronyms: fMRI (functional magnetic resonance imaging), fNIRS (functional near-infrared spectroscopy), EEG (electroencephalography), MEG (magnetoencephalography), PET (positron emission tomography), etc. (et cetera). These machines measure a variety of things, from electrical activity to blood flow, and they do their jobs quite well. They’re also enormous, expensive, and not easily condensed into helmet form.

In some cases the machines’ size owes in part to components that shield the patient’s head from the cacophony of electrical interference present in the world. This allows the sensors to avoid distracting signals and capture only what’s happening in the brain. Conversely, signals from the machines need to penetrate the human skull, which happens to be well-evolved to prevent penetration. That’s part of the argument for implants: They nestle sensors right up against our neurons, where the signals come in loud and clear.

It’s unlikely a helmet will ever gain the level of information an implant can, but Kernel has striven to close the gap by shrinking its sensors and finding artful ways to block electromagnetic interference. Among its breakthroughs, Johnson’s team designed lasers and computer chips that were able to see and record more brain activity than any previous technology. Month after month, the helmet became more refined, polished, and lightweight as the team made and remade dozens of prototypes. The only trick was that, to suit the different applications Johnson envisioned for the helmet, Kernel wound up needing to develop two separate devices to mimic all the key functions of more traditional machines.


A look inside the Flow.

One of the devices, called Flow, looks like a high-tech bike helmet, with several brushed aluminum panels that wrap around the head and have small gaps between them. Flip it over, and you’ll see a ring of sensors inside. A wire at the back can be connected to a computer system.

This helmet measures changes in blood oxygenation levels. As parts of the brain activate and neurons fire, blood rushes in to provide oxygen. The blood also carries proteins in the form of hemoglobin, which absorbs infrared light differently when transporting oxygen. (This is why veins are blue, but we bleed red.) Flow takes advantage of this phenomenon by firing laser pulses into the brain and measuring the reflected photons to identify where a change in blood oxygenation has occurred. Critically, the device also measures how long the pulse takes to come back. The longer the trip, the deeper the photons have gone into the brain. “It’s a really nice way to distill out the photons that have gone into the brain vs. ones that only hit the skull or scalp and bounced away,” says David Boas, a professor of biomechanical engineering and director of the Neurophotonics Center at Boston University.

The other Kernel helmet, Flux, measures electromagnetic activity. As neurons fire and alter their electrical potential, ions flow in and out of the cells. This process produces a magnetic field, if one that’s very weak and changes its behavior in milliseconds, making it extremely difficult to detect. Kernel’s technology can discover these fields all across the brain via tiny magnetometers, which gives it another way to see what parts of the organ light up during different activities.

The helmets are not only smaller than the devices they seek to replace, but they also have better bandwidth, meaning researchers will receive more data about the brain’s functions. According to the best current research, the Flow device should help quantify tasks related to attention, problem-solving, and emotional states, while Flux should be better suited to evaluating brain performance, learning, and information flow. Perhaps the No. 1 thing that has scientists gushing about Kernel’s machines is their mobility-patients’ ability to move around wearing them in day-to-day settings. “This unlocks a whole new universe of research,” Boas says. “What makes us human is how we interact with the world around us.” The helmets also give a picture of the whole brain, as opposed to implants, which look solely at particular areas to answer more specific questions, according to Boas.

Once their Kernel helmets arrive, Boas and his colleagues plan to observe the brains of people who’ve had strokes or suffer from diseases such as Parkinson’s. They want to watch what the brain does as individuals try to relearn how to walk and speak and cope with their conditions. The hope is that this type of research could improve therapy techniques. Instead of performing one brain scan before the therapy sessions start and another only after months of work, as is the practice today, researchers could scan the brain each day and see which exercises make the most difference.

Devices are also going out to Harvard Medical School, the University of Texas, and the Institute for Advanced Consciousness Studies (a California lab focused on researching altered states) to study such things as Alzheimer’s and the effect of obesity on brain aging, and to refine meditation techniques. Cybin Inc., a startup aiming to develop therapeutic mental health treatments based on psychedelics, will use the helmets to measure what happens when people trip.

All of this thrills Johnson, who continues to harbor the grandest of ambitions for Kernel. He may have given up on computer-interfacing implants, but he still wants his company to help people become something more than human.

A couple years ago, Johnson and I boarded his private jet and flew from California to Golden, Colo. Johnson, who has a pilot’s license, handled the takeoffs and landings but left the rest to a pro. We were in Colorado to visit a health and wellness clinic run by physician-guru Terry Grossman and have a few procedures done to improve our bodies and minds.

The Grossman Wellness Center looked like a cross between a medical clinic and the set of Cocoon. Most of the other guests were elderly. In a large central room, about 10 black leather chairs and matching footrests were arranged in a loose circle. Each chair held a couple of fluffy white pillows, with a metal pole on the side for our IV drips. A few of the ceiling tiles had been replaced and fitted with pictures of clouds and palm trees. In rooms off to the side, medical personnel performed consultations and procedures.

Our morning began with an IV infusion of two anti-aging fluids: Myers’ Cocktail-a blend of magnesium, calcium, B vitamins, vitamin C, and other good stuff-followed by a helping of nicotinamide adenine dinucleotide. Some of the IV fluids can trigger nausea, but Johnson set the drip to maximum and complemented the IV by having a fiber-optic cable fed into his veins to pepper his blood with red, green, blue, and yellow wavelengths of light for added rejuvenation. “I have to experience pain when I exercise or work,” he said, adding that the suffering makes him feel alive.

A few hours later, Johnson went into one of the treatment rooms with Grossman to get a stem cell injection straight into his brain. Earlier he’d provided 5 ounces of his blood, which had then been spun in a centrifuge so Grossman could separate out the plasma and put it through a secret process to “activate the stem cells.” Now, Johnson hopped onto a reclined exam table, lying on his back with his head angled toward the floor. Grossman pulled out a liquid-filled syringe. Instead of a needle at the end, it had a 4‑inch‑long, curved plastic tube, which the doctor coated with some lubricating jelly. He pushed the tube into one of Johnson’s nostrils, told the patient to take a big sniff, then pinched Johnson’s nose shut. They repeated the process for the other nostril. The procedure looked incredibly uncomfortable, but again, Johnson was unfazed, pulling in the stem cells with determination and excitement.

This snorting procedure-designed to improve mood, energy, and memory-was just a small part of Johnson’s overall health regimen. Each morning the CEO took 40 pills to boost his glands, cell membranes, and microbiome. He also used protein patches and nasal sprays for other jobs. After all this, he did 30 minutes of cardio and 15 minutes of weights. At lunch he’d have some bone broth and vegetables foraged by his chef from the yards of houses in Venice. He might have a light dinner later, but he never consumed anything after 5 p.m. He went to bed early and measured his sleep performance overnight. Every now and then, a shaman or doctor would juice him up with some drugs such as ketamine or psilocybin. He’d taken strongly enough to these practices to tattoo his arm with “5-MeO-DMT,” the molecular formula for the psychoactive compound famously secreted by the Sonoran Desert toad.

To make sure all his efforts were doing some good, Johnson had a lab measure his telomeres. These are the protective bits at the end of DNA strands, which some Nobel Prize-winning science has shown can be good indicators of how your body is aging. The longer the telomeres, the better you’re doing. Johnson used to register as 0.4 years older internally than his chronological age, but a couple of years into his regimen under Grossman, when he was in his early 40s, his doctors were telling him he was testing like a man in his late 30s.

During one of our most recent conversations, Johnson tells me he’s stopped snorting stem cells and experimenting with hallucinogens. “I got what I wanted from that and don’t need to mess with it right now,” he says. After many tests and much analysis, he’s discovered he operates best if he wakes up at 4 a.m., consumes 2,250 calories of carefully selected food over the course of 90 minutes, and then doesn’t eat again for the rest of the day. Every 90 days he goes through another battery of tests and adjusts his diet to counteract any signs of inflammation in his body. He goes to bed each night between 8 and 8:30 p.m. and continues to measure his sleep metrics. “I have done tremendous amounts of trial and error to figure out what works best for my health,” he says. “I have worked very hard to figure these algorithms out.”


Johnson eats once a day, first thing. Yes, including the wine.

In terms of what our birth certificates say, Johnson and I are the same age. He’ll turn 44 in August, a month before I do. To someone like me, who prizes late nights with friends, food, and drink, Johnson’s rigid lifestyle doesn’t exactly sound romantic. But it does seem to be paying off: When he last got tested, he had the exercise capacity of someone in his late teens or early 20s, and a set of DNA and other health markers pegged his age at somewhere around 30. As for me, I lack the courage to ask science what it makes of my innards and will go on celebrating my dad bod.

As Johnson sees it, had he not changed his lifestyle, he’d have remained depressed and possibly died far too young. Now he does what the data say and nothing else. “I did a lot of damage to myself working 18-hour days and sleeping under a desk,” he says. “You might earn the praise of your peers, but I think that sort of lifestyle will very quickly be viewed as primitive.” He says he’s at war with his brain and its tendencies to lead him astray. “I used to binge-eat at night and could not stop myself,” he says. “It filled me with shame and guilt and wrecked my sleep, which crushed my willpower. My mind was a terrible actor for all those years. I wanted to remove my mind from the decision-making process.”

The nuance in his perspective can be tricky to navigate. Johnson wants to both master the mind and push it to the side. He maintains, however, that our brain is flawed only because we don’t understand how it works. Put enough Kernel devices on enough people, and we’ll find out why our brain allows us to pursue addictive, debilitating behaviors-to make reckless decisions and to deceive ourselves. “When you start quantifying the mind, you make thought and emotion an engineering discipline,” he says. “These abstract thoughts can be reduced to numbers. As you measure, you move forward in a positive way, and the quantification leads to interventions.”

Of course, not everyone will want to make decisions based on what a helmet says their brain activity means. Taking the decisions out of thought patterns-or analyzing them for the purposes of market research and product design-poses its own, perhaps scarier, questions about the future of human agency. And that’s if the Kernel devices can fulfill the company’s broader ambitions. While the big, expensive machines in hospitals have been teaching us about the brain for decades, our understanding of our most prized organ has remained, in many ways, pretty basic. It’s possible Kernel’s mountain of fresh data won’t be of the kind that translates into major breakthroughs. The brain researchers who are more skeptical of efforts such as Johnson’s generally argue that novel insights about how the brain works-and, eventually, major leaps in brain-machine interfaces-will require implants.

Yet scientists who have watched Kernel’s journey remark on how the company has evolved alongside Johnson, a complete outsider to the field. “Everybody he’s recruited to Kernel is amazing, and he’s been able to listen to them and motivate them,” says MIT neuroscientist Edward Boyden. “He didn’t have scientific training, but he asked really good questions.” The test now will be to see how the company’s devices perform in the field and if they really can create a whole new market where consumers buy Flow and Flux helmets alongside their Fitbits and Oura rings. “There’s a lot of opportunity here,” Boyden says. “It’s a high-risk, high-payoff situation.”

If Johnson’s theories are correct and the Kernel devices prove to be as powerful as he hopes, he’ll be, in a sense, the first person to spark a broader sort of enlightened data awakening. He recently started a program meant to quantify the performance of his organs to an unprecedented degree. Meanwhile, he’s taking part in several experiments with the Kernel helmets and is still looking for ways to merge AI with flesh. “We are the first generation in the history of Homo sapiens who could look out over our lifetimes and imagine evolving into an entirely novel form of conscious existence,” Johnson says. “The things I am doing can create a bridge for humans to use where our technology will become part of our self.”