Both need to be loved and cared for. That works for humans. It works for dogs too.
In the shared arc of a life lived alongside dogs, scientists are finding an unexpected mirror for human aging — one that moves faster, speaks plainly, and may hold answers that decades of human study have not. The Dog Aging Project, enrolling more than fifty thousand dogs nationwide, rests on a quiet but profound observation: dogs grow old the way we do, from dementia to cancer to heart disease, but in a fraction of the time. For researchers like Matt Kaeberlein and Stephanie McGrath, and for participants like Pat Schultz — who watched both her husband and her dog slip into cognitive fog — the work is at once deeply personal and potentially transformative for all of us who age.
- Alzheimer's claimed Pat Schultz's husband Bill, and now her dog Murphy shows the same anxious, memory-dimmed decline — making her participation in aging research feel less like science and more like a second reckoning with the same loss.
- Roughly ninety percent of drugs that succeed in mice fail in humans, leaving a dangerous gap in aging research that dogs — larger, longer-lived, and naturally prone to the same diseases — may be uniquely positioned to bridge.
- A pilot study of rapamycin in dogs with dementia found fewer inflammation-producing brain cells in treated animals, mirroring results that extended mouse lifespan by sixty percent and raising urgent questions about whether the drug could do the same for dogs — and people.
- A larger NIH-funded clinical trial is now underway, with hundreds of dogs receiving rapamycin or a placebo, while biotech startup Loyal has raised over two hundred fifty million dollars racing to bring a daily longevity pill to market — with human applications squarely in sight.
- The science is converging on a single unsettling and hopeful idea: the biology of aging is conserved across species, meaning what slows decline in a dog may one day slow it in us.
Pat Schultz's husband Bill stopped recognizing her face near the end of his life with Alzheimer's. Their dog Murphy stayed close through it all — so close that Schultz clipped a tracking collar on him so he could follow Bill when he wandered. When Bill died two years ago, Murphy was still there. Now twelve years old and showing signs of cognitive decline himself, Murphy is enrolled in one of the most ambitious aging studies ever attempted.
The Dog Aging Project has enrolled more than fifty thousand dogs across veterinary clinics nationwide. The logic is elegant: dogs develop the same age-related diseases as humans — cancer, dementia, heart disease — while living in our homes, breathing our air, and sharing our habits. Crucially, they age far faster, compressing into five or ten years what would take a human lifetime to observe. Co-founder Matt Kaeberlein realized early on that methods proven to slow aging in lab animals might translate to dogs, and from dogs, to people.
Veterinary neurologist Stephanie McGrath focuses on the aging brain. She notes that dogs offer something mice cannot — naturally occurring diseases in a larger animal that closely mirror human conditions. When she tests Murphy's memory during a clinic visit, the dog struggles, anxious and reluctant. His performance has declined across visits. The anxiety itself, she suggests, may be an early sign of dementia.
The project has already produced meaningful findings: dogs living with other dogs get fewer diseases, and those that don't exercise face six times the odds of developing dementia. But the most compelling work involves rapamycin, a drug that extended mouse lifespan by sixty percent. In a small pilot study, dogs that received it showed fewer inflammation-producing brain cells — the kind implicated in dementia — compared to those on a placebo. Neuropathologist Dirk Keene, who has studied human Alzheimer's brains for twenty years and watched both his mother and his dog Spring decline from what looked like the same disease, provided a striking visual: a human brain hollowed by dementia beside a dog brain with identical damage, and under magnification, beta amyloid plaques in Spring's brain nearly indistinguishable from those in humans.
A larger clinical trial, partly funded by the NIH, is now testing whether rapamycin extends healthy lifespan in hundreds of dogs. Murphy is among them. Pat Schultz won't know for years whether he received the drug or a placebo. What she knows is simpler: both her husband and her dog needed the same thing as they declined — to be loved, to have a hand held or a head patted, to have their fear eased by presence.
Beyond the university labs, Silicon Valley has taken notice. Loyal, a biotech startup founded in 2019, has raised over two hundred fifty million dollars to develop a daily longevity pill for dogs — beef-flavored, preventative, aimed at adding roughly a year of healthy life. The FDA has already cleared the safety data for one of their compounds. The company's founder sees dogs as the fastest route to understanding human aging biology. If the drugs work in canines, the next market — worth billions — is obvious.
Pat Schultz's husband Bill stopped recognizing her face. In the fog of his Alzheimer's disease, he asked her out on dates as if they were strangers. Through it all, their dog Murphy stayed close—so close that Schultz clipped a tracking collar on the German shepherd-poodle mix so she could follow Bill when he wandered, using the dog as an anchor to a man slipping away. When Bill died two years ago, Murphy was still there. Now, at twelve years old, Murphy is part of something larger than one family's grief: a sprawling scientific effort to understand why we age, and whether we can slow it down.
The Dog Aging Project has enrolled more than fifty thousand dogs across hundreds veterinary clinics and hospitals nationwide, including Colorado State University's College of Veterinary Medicine. The premise is deceptively simple: dogs get old the same way humans do. They develop cancer, dementia, heart disease. They live alongside us, eat what we eat, breathe the same air, exercise with us or don't. But here's the crucial difference—they age much faster. What would take eighty years to study in a human takes five or ten in a dog. Matt Kaeberlein, a biologist who co-founded the project in 2014 after decades studying the mechanisms of aging, describes the moment the idea crystallized: he realized that several methods proven to slow aging in laboratory animals might work in dogs, and if they worked in dogs, they might work in people.
Stephanie McGrath, a veterinary neurologist at Colorado State, joined Kaeberlein to focus on how the brain ages. She points to a stark problem in drug development: roughly ninety percent of treatments that succeed in mice fail in humans. Dogs offer something in between—a larger animal with naturally occurring diseases that mirror human aging. When McGrath tests Murphy's memory, showing him where a treat is hidden and then asking him to retrieve it, the dog struggles. He's anxious, reluctant to leave Pat's side. On a second attempt, he finds the treat, but barely. McGrath notes that his performance has declined noticeably over recent visits. The anxiety itself may signal early dementia.
The research has already yielded concrete findings. Dogs living with other dogs suffer fewer diseases. Dogs that don't exercise have six times greater odds of developing dementia. But the most promising work involves a drug called rapamycin. In mice, it slowed cognitive decline and extended lifespan by sixty percent. A pilot study of twelve dogs with dementia signs tested whether it might work in canines. One dog, Monkey, received rapamycin; another, Qbert, got a placebo. When the dogs died and their brains were examined under a microscope, Monkey's showed fewer microglial cells—the inflammation-producing cells implicated in dementia. Two other dogs on rapamycin, including one named Ralph, showed the same pattern. The drug appeared to work.
Dirk Keene, a neuropathologist from the University of Washington who has spent twenty years studying human brains for Alzheimer's causes, participated because he watched both his mother and his dog Spring decline from what looked like the same disease. He showed the physical evidence: a human brain ravaged by dementia, shrunken and hollow, beside a dog brain with identical damage. Under magnification, Spring's brain displayed beta amyloid plaques—the hallmark of Alzheimer's—that looked strikingly similar to those in human brains. The biology of aging, Kaeberlein explains, is conserved across the animal kingdom. Much of what happens in dogs happens in people.
The Dog Aging Project is now running a larger clinical trial, funded partly by the National Institutes of Health, giving hundreds of dogs either rapamycin or a placebo to see if the drug extends healthy lifespan. Murphy is enrolled. Pat Schultz won't know for years whether her dog received the real drug or a placebo, but she's focused on what she can control: making sure both she and Murphy age as well as possible. When asked what she's noticed in common between caring for her husband with Alzheimer's and caring for an aging dog, she says simply that both need to be loved and cared for. Holding a hand, patting a head—these small acts ease anxiety and fear. They work for humans. They work for dogs too.
Meanwhile, Silicon Valley is betting heavily on longevity. Loyal, a biotech startup founded in 2019 by thirty-one-year-old Celine Halioua, has raised more than two hundred fifty million dollars to develop aging drugs for dogs. The company's vision is a daily beef-flavored pill, preventative like a statin, that might extend a dog's healthy lifespan by roughly one year. The FDA has already approved the safety data for one of their drugs and says it has a "Reasonable Expectation of Effectiveness," though final results won't arrive for several years. Halioua sees dogs as the fastest path to understanding human aging biology. If the drugs work in canines and prove safe, the next step is obvious. The real market—the multi-billion-dollar one—lies in humans.
Citações Notáveis
If it works in a dog, and it's safe, and it's helping their cognition, then maybe it would help humans.— Julie Moreno, molecular biologist, Colorado State University
The biology of aging is so conserved or shared across the animal kingdom. Much of this works the same way in dogs. Much of it works the same way in people.— Matt Kaeberlein, biologist and co-founder of Dog Aging Project
A Conversa do Hearth Outra perspectiva sobre a história
Why does a dog's brain matter so much for understanding human aging? Couldn't you just study humans directly?
You could, but it would take your entire life. A human study from age one to eighty takes eighty years. A dog study takes five to ten. You get decades of data compressed into a single research career.
But aren't dogs just... different from us? Different biology, different brains?
That's what you'd think, but they're not. Dogs develop the same diseases we do—cancer, dementia, heart disease. Their brains have the same lobes, the same structure. When dementia damages a dog's brain, it shrinks and hollows out exactly like a human brain does.
So you're saying if a drug works in a dog, it will work in a human?
Not necessarily. But it's far more likely than if it only worked in mice. Ninety percent of mouse treatments fail in humans. Dogs are bigger, they live longer, their biology is closer to ours. They're the missing link.
What about the people in these studies? What are they getting out of it?
Some are motivated by loss. Pat Schultz watched her husband disappear into Alzheimer's. Now she's watching her dog age, and she's part of research that might help the next person avoid what her husband went through. She may never know if Murphy got the real drug or a placebo, but she knows the data matters.
And the dogs themselves—are they being helped?
That's the hope. If rapamycin works, if these other drugs work, then yes. But even if they don't, the dogs are being monitored closely, cared for, studied. Their brains might teach us something that saves thousands of human lives. That's not nothing.