A San Francisco company developing drugs meant to extend the healthy lifespan of dogs, pursuing a first-of-its-kind FDA pathway for a canine longevity indication.

Facts
Legal name
Cellular Longevity, Inc.
Founded
2019
Founder
Celine Halioua
Headquarters
San Francisco, California
Focus
Drugs to extend healthy lifespan in dogs

Overview

Loyal is an American biotechnology company, formally named Cellular Longevity, that is developing drugs intended to extend the healthy lifespan of dogs. Founded in 2019 by Celine Halioua and based in San Francisco, Loyal has pursued an unusual regulatory goal, to win approval for a medicine whose labeled purpose is lifespan extension itself, rather than the treatment of a single named disease. That ambition places the company at the intersection of veterinary medicine and mainstream aging research. Dogs are more than a business opportunity for the company; they are also a scientific argument, since pet dogs share human homes, diets, and many environmental exposures, and develop age-related diseases that resemble our own, which makes canine aging a useful and ethically distinct model. Halioua began the company after working in longevity science and venture investing, arguing that dogs offered a faster and more honest path to a genuine anti-aging drug than human trials, which would take decades to read out.

The drug programs

Loyal's pipeline reflects two distinct ideas about why dogs age and die. The first targets body size. Through generations of selective breeding, large dogs grow quickly and tend to carry high circulating levelsCompanyLevelsA metabolic health company whose app turns continuous glucose monitor data into personalized feedback on how food, sleep, and exercise affect blood sugar.Company → of insulin-like growth factor 1, or IGF-1, a hormone that drives growth but that in excess is associated with faster aging and shorter life. Big breeds such as Great Danes typically live far shorter lives than small ones, and Loyal's large-dog programs, an injectable candidate called LOY-001 and an oral pill called LOY-003, aim to lower IGF-1 signaling to slow that accelerated aging. The second idea targets the metabolic dysfunction of old age more broadly. LOY-002, the company's lead candidate, is a daily pill intended for senior dogs, generally those aged around ten and over and above a modest weight, meant to improve metabolic health in later life. The programs connect to familiar themes in geroscienceTermGeroscienceThe field studying how aging mechanisms drive multiple chronic diseases and how targeting them might extend healthspan.In glossary → and the hallmarks of agingArticleHallmarks of AgingA shared framework that organizes aging into interconnected biological processes, giving longevity research a common map of what to measure and target.Read entry →, including the growth and nutrient-sensing pathways also implicated in caloric restriction and drugs such as rapamycin and metformin.

The FDA pathway

What sets Loyal apart is its work with the United States Food and Drug Administration to establish that a drug can be approved specifically to extend canine lifespan. Working through the agency's Center for Veterinary Medicine, the company has pursued conditional approval, a route that can allow a drug onto the market while a larger confirmatory study continues. Approval requires clearing several technical sections covering effectiveness, safety, and manufacturing. In late 2023 the FDA agreed that Loyal's data supported a reasonable expectation of effectiveness for extending lifespan in large dogs, a milestone the company described as the first time the agency had accepted that a drug could reasonably be expected to lengthen a dog's life. The agency later accepted a similar effectiveness case for the senior-dog program, and in early 2026 accepted the safety package for that candidate, leaving manufacturing as a remaining step. To confirm real-world benefit, Loyal has also run a large multi-year field study enrolling thousands of older pet dogs.

Dogs, humans, and reception

Loyal's work overlaps with academic efforts such as the Dog Aging Project, a separate university-led study testing whether rapamycin can extend healthy life in companion dogs. Both rest on the premise that if an intervention slows aging in a genetically diverse, environmentally realistic population of dogs, it strengthens the case that similar biology might be addressed in people, using shared biomarkers of aging to measure progress. Supporters view Loyal as a pragmatic route to test the geroscienceTermGeroscienceThe field studying how aging mechanisms drive multiple chronic diseases and how targeting them might extend healthspan.In glossary → hypothesis in a real population within years rather than decades. Critics urge caution, noting that no Loyal drug had completed the full approval process and reached the market as of early 2026, that lifespan claims are inherently hard to prove, and that demonstrating that a healthy animal lives meaningfully longer without offsetting harms is a high bar. The company itself frames its drugs as candidates still under review, carefully separating its aspirations from what regulators have so far accepted.

TagsCanine LongevityAgingVeterinary MedicineBiotech