For most people, dogs are more than pets. They are companions, protectors, and, in many cases, family. They improve their owners’ mental and physical health, and their presence has even been linked to making people appear more attractive. But the bond between humans and dogs is inevitably limited by biology: canine lives are heartbreakingly short.
Two major research efforts—one led by a San Francisco biotech start-up, the other by a university-based longevity study—are now working to change that. If successful, they could extend dogs’ lives by years, while also producing insights that might someday help humans live longer, healthier lives.
Loyal, a San Francisco company founded by 30-year-old scientist and entrepreneur Celine Halioua, has developed LOY-002, a beef-flavored pill designed to slow age-related decline in dogs. The goal is not immortality, Halioua says, but a meaningful extension of healthy years by targeting the metabolic changes associated with aging. Loyal hopes to launch the pill next year under the FDA’s conditional approval program for innovative veterinary drugs. If successful, it would be the first medication explicitly designed to lengthen canine lifespan.
The company has attracted $135 million in investment from firms including Bain Capital, Khosla Ventures, and Valor Equity Partners, and is valued at $425 million. The potential market is vast: the U.S. has roughly 90 million dogs in 60 million households, with pet spending rising steadily year over year. Loyal’s trials—already the largest animal clinical study ever conducted—have enrolled more than 1,300 dogs at over 70 veterinary clinics.
Halioua says her interest in longevity began with frustration at how medicine waits for diseases to appear before intervening. Inspired by long-term studies showing that caloric restriction can lengthen dogs’ lives, she left a Ph.D. program at Oxford to work in venture capital, then launched Loyal in 2020. Her company’s pipeline includes a second drug aimed at reducing growth hormone in large dogs, whose lifespans tend to be shorter than smaller breeds.
Across the country, the Dog Aging Project at the University of Washington is studying rapamycin, an existing human drug used to prevent organ transplant rejection. In mice, rapamycin has extended lifespan and delayed or reversed age-related decline. The Dog Aging Project is the first large-scale, long-term study of aging in large animals living in natural environments, and it is investigating whether low doses of rapamycin could give dogs an additional three healthy years.
The project also has the potential to shed light on human aging. Because dogs share our environments and develop many of the same age-related diseases, researchers believe findings in canine longevity could translate into human medicine more effectively than results from laboratory mice. Co-director Daniel Promislow says the work is equivalent to a 40-year human trial—something impossible to conduct with people.
Researchers are also exploring how data from dogs can inform women’s health, particularly around menopause, by comparing outcomes for dogs spayed at different ages. That research, says chief veterinary officer Kate Creevy, could have “interesting translational impacts” for understanding hormonal changes in women.
Experts in the human longevity field are watching closely. Tom Rando, director of the University of California’s Broad Stem Cell Research Center, calls the work “fascinating” and says that demonstrating safety and efficacy in dogs would strengthen the case for human trials. But as gerontology professor Jamie Justice points out, without an agreed-upon biomarker of human aging, any drug—no matter how promising—faces steep regulatory hurdles before it could be tested in people.
For now, the focus remains on the animals already by our sides. Loyal’s Halioua believes the company is on the cusp of something transformative. “I think the general public will be blown away when they realize they can go to the vet and get a drug to extend their dog’s lifespan,” she says. And if the science works for dogs, many will inevitably ask the next question: why not us?
