The Search for a Pill That Can Help Dogs—and Humans—Live Longer

She also became uncomfortable with the SENS Research Foundation and its animating spirit, de Grey. She initially admired the foundation, she says: “They had a lot of glitz and glam for me.” She was impressed by the organization’s formal dinners, where rich and distinguished men were encouraged to donate to the war on aging. But she started to suspect she was only being invited “because I was a cute young girl,” she says. “Also smart, but that wasn’t what they cared about.” At one dinner, she says, de Grey plied her with alcohol and told her that as a “glorious woman” she had a duty to have sex with potential donors to encourage contributions. (After Halioua went public with her allegations several years later, de Grey denied making the statements.)

By 2018, Halioua was looking for an escape route. “I really snapped because of all of that stuff Aubrey and my professor did,” she says. “It created this desire to create my own sphere of influence, where I control the rules.” She turned to one of the only prominent women in the small circles working on aging treatments, Laura Deming. Deming was a wunderkind who had started working at age 12 in Cynthia Kenyon’s lab, enrolled at MIT at 14, dropped out after receiving a fellowship from Peter Thiel, and now ran a venture capital fund in San Francisco to bring aging-related startups into the Silicon Valley mainstream. (One of her latest projects involves developing technology to freeze organs without damaging them.) Halioua had once been introduced to Deming through de Grey, and now she emailed in pursuit of an internship.

Deming arranged a brief phone interview. Halioua was “very intense,” Deming recalls. “I asked her a question about Markov models”—a math trick to analyze processes that change over time—“and could tell that she didn’t have the exact answer but was determined to figure it out on the call” by wringing every possible clue from what Deming said. “That was really cool.” The internship was only two weeks long, but for Halioua it was enough—a refuge and perhaps a new beginning. In early 2018, she flew to California.

HALIOUA JOINED DEMING at a WeWork in the Tenderloin, a San Francisco neighborhood abutting City Hall and the headquarters of Twitter that is also rife with human misery and crime. Stepping out of the office at night felt risky in a way it never had in Oxford or Austin. Working in venture capital felt unfamiliar too. At Oxford, grad students and researchers left the lab at 5 pm and went home or to the pub. Important emails were long and formal. In San Francisco, entrepreneurs and investors worked late and then spent hours more, over fine dinners, debating the intellectual foundations of their theories about the future.

At the end of Halioua’s brief internship, Deming offered her a job. She found a way to accept but also complete her PhD in Oxford, and began flying back and forth. Halioua felt the arrangement was working at first, but relations with her supervisor worsened, and in the fall of 2018 she filed a formal complaint under Oxford’s bullying and harassment policy. He left the university soon after, but Halioua found her department’s investigation to be painfully slow. (The head of her former department, Georg Holländer, declined to comment on the case, but said: “all complaints will always be considered carefully and rigorously under our procedures.”) While she waited for its official assessment, she began to have panic attacks. “You kind of feel like you’re crazy,” she says. “Everybody tells you you’re being sensitive or misinterpreting what this person said to you.” Working for Deming began to soak up more of Halioua’s time and enthusiasm, and she left Oxford for good.

Halioua knew next to nothing about venture capital or Silicon Valley, but she poured herself into reading pitch decks, networking with founders, and drafting investment memos. She started to tweet, blasting out news of pharma deals, photos of San Francisco beaches, her Fitbit stats, and appreciation of Elon Musk. She helped bring about investments in Fauna, a startup exploring the age-defying biology of hibernation, and Gordian Biotechnology, which aims to fight diseases of aging by modifying a patient’s DNA. By the time news came from Oxford that it had upheld the majority of her complaints, almost a year after she had filed them, Halioua knew her future lay in biotech, not academia.

Halioua’s own company, Loyal, emerged from one of her early projects for Deming, a dense, roughly 50-page memo on the investment potential of the biochemical pathway Cynthia Kenyon had used to double the lifespan of worms. In many species—including humans—it involved a hormone called insulin-like growth factor 1, which adjusts an animal’s growth and metabolic response to food. Tinkering with this pathway could extend the lifespan of flies, worms, and mice.

Unfortunately for Halioua, the literature seemed less rich in clues for how to turn this knowledge into a drug for people. The role of IGF-1 in human aging was unclear, and although the pathway was clearly implicated in certain eye diseases unrelated to aging, Halioua couldn’t get excited about working on them.

In the summer of 2019, Halioua was drunk on a camping trip among strangers when a factoid she had omitted from the report came back to her. Organized by the founders of an autonomous trucking startup, the trip brought together a group of young entrepreneurs and investors. Around the campfire, she joked—purely as an icebreaker—that she knew how to extend a dog’s lifespan because IGF-1 was implicated in dog body size and longevity.

Her quip took on a life of its own and became lodged in the collective consciousness of Silicon Valley. One investor on the trip mentioned Halioua’s idea to a founder he knew, who in turn told it to Greg Rosen, a venture capitalist. Inspired by the South Korean scientists who had produced the first cloned dog, an Afghan named Snuppy, Rosen was looking for an entrepreneur to start a US company to clone dogs for bereaved owners. When Rosen and Halioua met for coffee in downtown San Francisco, he realized she had a better solution for the same underlying problem—that a dog never lives long enough.

HALIOUA BEGAN 2020 with $5.1 million in funding. By way of thanks, she sent all of her investors, including Rosen, fluffy toy puppies wearing company bandanas. She secured an office on the edge of downtown San Francisco, but the lease began in March, the same month the Bay Area became the first part of the US to enter pandemic lockdown. Her company’s formative months, and first hires, took place via Zoom, Slack, and eventually socially distanced meetups. Halioua raised another $6 million and hired scientists, veterinarians, and an expert in getting new animal drugs past the FDA.

She embraced the role of dog company CEO—painting a mural of a giant German shepherd in Loyal’s office and ordering shirts with the slogan “Save the dogs, save the world.” She adopted a fluffy white husky named Wolfie, whom she has described as her cofounder and Loyal’s chief evangelist. Her management style, she says, was informed by her bad experiences at Oxford. When she talks to her team about her goals or beliefs, she tries to pair her statements with evidence to convince her workers that the boss is being straight with them. “Even if you don’t trust me, you still know this is true,” she says.

Halioua’s new science team, including a scientist who previously led aging research at pharma giant Regeneron, helped refine her original idea. They identified a compound they believed could be given to young dogs of the largest breeds, such as French mastiffs, to delay their accelerated aging process. They found a second compound they thought could target processes that cause cognitive decline and kidney problems in older dogs of all sizes.

As her company gained traction, Halioua noticed specific patterns in her business interactions. She tried to recruit women investors but found it difficult because there weren’t many to ask. When she met with investors who were men, some would try to flip a business meeting into a date, and others would confidently explain science to her that she knew inside out. Mostly she brushed off such moments—her time at Oxford had lowered her expectations of those with more power and prestige than her.

She often felt different. Describing herself as an “Oxford dropout” helped convince people to take her seriously—never mind that she had left her Ph.D. in part due to dissatisfaction with a harassment investigation, a circumstance missing from the dropout tales of archetypal boy geniuses like Mark Zuckerberg. She listened to hundreds of Silicon Valley podcasts to try to learn the industry’s patois. She trained herself to smile less and wrote in a blog post aimed at women entrepreneurs: “I come off as more of a grump now, but I am a grump who has the money she needs to build her company.”

In the spring of 2021, Halioua published a blog post about her Oxford PhD supervisor titled “The Gifts of My Harasser,” leaving him nameless. She described the paradox of one of her worst experiences laying a foundation stone for her later successes by teaching her to be skeptical of social hierarchies and institutional power. “It’s been two years since I left. I have not broken anymore, but I still feel the cracks,” she wrote. “His abuse shattered my preconceived notions of how the world worked and cleared a path I otherwise never would have found.”

Halioua also still felt the burden of her experience with de Grey, the aging guru of the SENS Research Foundation. Deming, too, had endured an uncomfortable experience with de Grey, whom she had known since she was 14. Days before her 18th birthday, Deming had emailed de Grey, then 48, asking him to introduce her to someone. In his reply, he suggested he was interested in Deming sexually. “I have a fairly adventurous love life, and I’m not coy in talking about it, but I’ve always taken care to avoid letting conversations stray in that direction with someone so young as you,” de Grey wrote. “That has always felt quite jarring given that I could treat you as an equal on every other level. Maybe those days are over … Ahem – back to business 🙂 Yes, I’ll e-introduce you.” (De Grey later said the email was “an error in judgment.”)

Now, in June 2021, Deming and Halioua heard that de Grey might be mentoring another underage girl. The two women decided to formally report their experiences to the foundation, in the hope that doing so might protect this girl and others. The organization quickly retained a law firm to investigate the allegations and placed de Grey on leave. But in the weeks afterward, the nonprofit promoted social media posts featuring de Grey discussing a cryptocurrency fundraising campaign that would net the organization $25 million.

By August, Halioua says she and Deming became worried that the nonprofit was too conflicted to properly investigate itself, and they decided to go public. Late one Tuesday afternoon, the two women simultaneously posted detailed statements to their personal websites. Word spread fast, as did Halioua’s accompanying Twitter thread, prompting an outpouring of sympathy online, a round of media coverage about the allegations, and denials from de Grey.

Just over a week later, the SENS Research Foundation said its board learned that de Grey had attempted to undercut the ongoing investigation—by sending emails intended to pressure a participant in the inquiry, according to the official report of the investigation—and decided to “separate” from him immediately. The foundation’s law firm would later uphold Halioua’s and Deming’s accounts of these events. De Grey says that the women were tricked by people aiming to eject him from his nonprofit and that he has “never said anything to Laura or Celine verbally or otherwise that had improper intent.”

Halioua felt sure she had done the right thing, and she reasoned that Loyal had progressed enough that her career was not in danger. She was also too busy to dwell on the uproar. In late August her team announced that the NIH’s National Institute on Aging would collaborate with Loyal to test two of the company’s compounds, as part of a program on extending the longevity or healthy lifespan of mice. Three weeks later she turned 27. She rounded out the month by disclosing that Loyal had raised an additional $27 million in investment funding. Half of her new investors were women.

IN 2022, HALIOUA and her team, approaching 70 strong, began to flex the scientific muscles needed to upend conventional wisdom about aging. They analyzed and published data collected the previous year from nearly 500 dogs who were brought to a vet clinic for a health assessment. For a second study, they recruited some 2,000 owners—Halioua usually calls them “pet parents”—to receive Loyal-branded doggy DNA swab kits that might help them understand the markers of aging. Dog lovers on social media quickly picked up the scent; both studies filled up fast, and Halioua’s inbox was flooded with unsolicited dog pics. (Halioua says she has nothing against cats—and has even hired a few cat fanciers—but that their long lives, dislike of medicine, and not-very-humanlike physiology make them a less appealing target. “They’re like little biological aliens,” Halioua says.)

Less publicly, Loyal is preparing for the clinical trials of its two products. Halioua isn’t giving away many details about Loyal’s drugs, but she does say that both medicines have performed well when given to lab dogs. One is a pill that might delay the onset of age-related diseases such as dementia and kidney failure, two common reasons for owners to have an animal put down. Halioua says it uses some pathways seen in caloric restriction. Now the company is testing the drug in pet dogs, and she anticipates she’ll launch a full clinical trial designed to win regulatory approval next year. The second drug, released slowly by an implant, might dampen the cellular processes that are believed to condemn the largest dog breeds to short lives.

As is standard in the drug industry, the company will seek the FDA’s sign-off on its study designs first. That step is a big deal for Loyal, because the agency would be backing the notion that drugs can be tested and proven to boost longevity. That is, not to prevent a disease or slow one down, but to hit a whole suite of ailments by tackling aging at its root.

To navigate the scientific and regulatory hurdles, human longevity startups—Loyal’s nominal competitors—have taken to focusing on drugs that tick two boxes: They are effective enough to get first approved as a conventional treatment for a single disease, and they hold broad antiaging effects. The hope is that once the drug is benefiting patients, data will pile up that helps prove its general preventive powers against age-related disease.

James Peyer, a former venture capitalist who is CEO and cofounder of antiaging startup Cambrian Biopharma, has raised more than $160 million with that tack. He says that establishing a rich portfolio of nearly 20 potential drugs for humans helped win investors over. But he admits his two-step approach isn’t the only way to go, and it’s possible that Halioua, whom he has known for years, might have hit on a faster way to get an antiaging drug for humans. “Part of Celine and Loyal’s brilliance is that they found a completely different path,” he says, one that lets her focus solely on the drugs’ antiaging properties right from the start. If the mechanisms that Halioua’s team finds in dogs align with human biology—a considerable unknown—the company could be well positioned to jump species, Peyer says.

Loyal is not the only outfit trying to understand canine longevity. The Dog Aging Project, led by the University of Washington and Texas A&M College of Veterinary Medicine and Biomedical Sciences, has completed two small studies in which owners were given rapamycin or placebo pills without being told which. People who dosed their dogs with the drug reported that their pets became more active, says Matt Kaeberlein, a University of Washington professor who is co-director of the project and an adviser to Loyal. He suspects that rapamycin worked by soothing arthritis or other aches and pains, and he hopes to gather firm proof in a larger trial of about 600 dogs.

Kaeberlein has studied life-extending genes and treatments in yeast, worms, and mice and is convinced some aging mechanisms are shared across the animal kingdom. “Obviously I don’t know whether rapamycin is going to have a big effect on lifespan and health span in dogs, but I am as certain as I can be that something will,” he says. He declines to say whether he gives rapamycin to his own dog, Dobby, an 11-year-old German shepherd, saying it wouldn’t be proper to comment on such use while running a trial investigating the same. But Kaeberlein will say that he takes the drug himself and believes it helped resolve an attack of frozen shoulder, a mysterious condition in which the joint becomes stiff and painful.

Like other veterans of academic aging science—and Halioua—Kaeberlein exudes levelheaded excitement but also impatience when asked about the future of aging treatments. Piles of evidence suggest it is possible to slow down the processes of aging in humans, or any other animal. Do you want that pill to exist? Just give scientists the time and money—and regulatory support—to figure it out, says Nir Barzilai, director of the Institute of Aging at Albert Einstein College of Medicine, in New York.

“Right now we need to start making progress with drugs that maybe wouldn’t make us live 150 years but will make us healthier for much longer,” Barzilai says, by delaying the onset of diseases such as cancer or Alzheimer’s. He has spent years trying to secure funding for a six-year human clinical trial to investigate whether a common diabetes drug can delay aging. He is less sure of Loyal’s approach, but he figures longer-lived and more active dogs could produce other effects in humans: more active, longer-lived owners, and more support for aging research.

Sitting cross-legged on an easy chair in Loyal’s San Francisco office, Halioua argues that Loyal can break the psychological barriers holding back the war on aging. “Many people don’t know that we’ve extended lifespan in mice many times, and even if they do, well, it’s a mouse,” she says, as Wolfie lolls nearby on a sunny cushion next to a floor-to-ceiling window. What would kick the field into a higher gear, she says, is a proof of concept that’s more persuasive and lovable than a wizened lab rodent.

She imagines appearing onstage one day with a healthy Great Dane that is 15 years old, almost twice the breed’s usual age—and thus persuading people to see aging science not as a realm of weird ideas and thinkers but as a conventional branch of biotech. Silicon Valley founders are often celebrated for creating products that cause jaws to drop and heads to explode. Halioua may make her greatest mark by killing hype rather than creating it, transforming the notion that drugs can extend life into an everyday comfort—like a faithful friend’s tail wagging when you walk through the door.