What a time to be a dog. Right now, it’s estimated that owners spend around £2,000 (about $2,600) a year to take care of our favourite four-legged friends (sorry, cats), with that figure including up to £600 (almost $800) on grooming and £300 (nearly $400) on treats.
But modern pooches aren’t only pampered – they’re enjoying longer, healthier lives than ever. One study of dogs in Japan found that their lifespans have increased by over 50 per cent since the 1980s.
That figure could rise further. A wave of cutting-edge canine science is sweeping the globe, with everything from the Dog Aging Project’s 50,000-pet study, to biotech firms racing to develop anti-ageing drugs for dogs.
It all means we could be less than a decade away from cracking the code of animal longevity.
And the best bit? These breakthroughs could unlock new ways for humans to live longer, healthier lives, too.
Dog breeds age differently
A lot of us think of the ageing process as an inevitable side-effect of being alive. As we get older, both people and pooches go grey, get slower and eventually succumb to a very similar collection of diseases, from arthritis to cancer.
But we now know that many of the diseases that come with growing older are caused by common biological processes. And some scientists believe a single pill could be developed that targets the underlying biology of ageing, which could keep many (or all) of these diseases at bay.
This is where dogs come in. Thanks to the enormous diversity between breeds, studying differences between them could help reveal a lot about the ageing process.
Think about it. Whether it’s an Afghan hound or a yorkshire terrier, all domestic dogs belong to the same species – Canis familiaris. This means they all share the vast majority of their genes.
Their DNA is similar enough that dogs from different breeds can mate and give birth to puppies, from the labradoodle (labrador and poodle) to the puggle (pug plus beagle).
Yet although the genetic differences are few, the variety among dogs is huge – in how they look, how they act and how long they live. Some breeds, like the presa canario (a type of Spanish mastiff), live on average just 7.7 years. Others, like the miniature dachshund, can live nearly twice as long.
But surely, as you might be thinking, aren’t the differences in lifespan all down to a breed’s size? Well, yes, it’s certainly a factor – as dog lovers are sadly aware, bigger dogs tend to live shorter lives.
A US study of almost 10 million dogs found that ‘giant’ breeds lived an average of 9.5 years, while ‘small’ breeds lived 13.5 years. That’s over 40-per-cent more time chasing sticks and barking at postal workers than the biggest dogs.
One reason for this could be risk of cancer – the more cells you have, the more chances you have for one of them to accrue the wrong combination of genetic mutations and turn into a tumour.
(Tall humans reading: don’t worry. While being taller is linked to a slightly increased risk of cancer, it’s also associated with a lower risk of heart disease. When it comes to overall lifespan, these effects likely balance each other out.)
But here’s the thing: size doesn’t determine a dog’s lifespan completely. For instance, among giant breeds, a great pyrenees (a very large mountain dog) lives about 11.5 years on average, while a similarly giant caucasian shepherd dog lives only around 5.4 years. This means that other genetic factors are at play.
That’s because ageing is incredibly complicated. But ultimately, dogs show us how small genetic differences between breeds can drive big differences in longevity. And this suggests that it might be easier than we think to have an influence on ageing.
Read more:
- Here's how to tell if your dog actually loves you, according to science
- Cats v dogs: Here's who's smarter, according to science
The Dog Aging Project
If just a few genes can shape how long an animal lives, could something as simple as a pill help do the same?
Dogs are a fantastic place to test this theory. Firstly, as previously mentioned, they get similar diseases to humans as they age.
Secondly, dogs are almost unique in how closely they share our environment. Unlike lab mice, who live in sterile, climate-controlled cages, our pets breathe the same air we do, drink the same water and often share our daily routines – not to mention our snacks and, if they’re lucky, our beds.
Thanks to thousands of years of domestication, dogs have gut bacteria (microbiomes) far more similar to ours than those of mice or pigs.
Also, while sad for their owners, dogs’ shorter lifespans are an advantage for longevity experiments. The longer an animal lives, the longer you have to wait to find out if your longevity treatment worked. This makes medium-to-large dogs, with their ten-year lifespans, a more practical starting point than humans.
Combined, all of this convinced longevity scientists Professors Daniel Promislow and Matt Kaeberlein to launch the Dog Aging Project in 2014.
“I think what really got me excited,” Kaeberlein says, “was realising that we could not only understand the biology of ageing in dogs, but also apply interventions that have already been shown to slow ageing, extend lifespan and improve healthspan in mice. Almost certainly, some of them will work similarly in dogs.”
“I’m a dog person. I’ve always had dogs,” says Kaeberlein. “Obviously, I wanted that for my dogs. I want that for everyone else’s dogs, too.”
A big part of the Dog Aging Project is what’s called a longitudinal study, which basically means researchers track the same dogs over time to understand how they age.
By collecting detailed questionnaires from the owners of 50,000 participating pooches, the team is already uncovering some fascinating insights into what helps dogs stay healthier for longer.
Intermittent fasting, but for dogs
One early finding of the Dog Aging Project: how often dogs eat may influence how long they live.
“It turns out that dogs fed once a day are at a lower risk of developing several age-related conditions,” Kaeberlein says. “It was completely not what I expected! I’ve never been a big believer in time-restricted eating as a longevity intervention.”
However, because this is an observational study, it’s hard to untangle cause from effect. Maybe less frequent feeding leads to better health, or maybe dogs in poorer health are simply fed more often, perhaps to take medication.
“But it’s still a really interesting observation that seeds a whole bunch of potential studies in the future,” says Kaeberlein.
So, does this mean you should shun breakfast and lunch in favour of one supersized supper? Perhaps not.
One human trial of the ‘one meal a day diet’ has suggested it can lead to slightly worsened measures of health – plus, it’s not exactly easy to stick to (you’ll likely be starving by mid-afternoon).
Still, the Dog Aging Project’s findings are worth watching. If future research (including a proper randomised trial) confirms that less frequent feeding really does boost canine health, scientists could dig into the biological reasons behind it.
A pill to mimic the benefits of fasting
That could eventually lead to a pill that mimics the benefits in humans – no extreme diets required. Intriguingly, this very drug may already exist – it’s called rapamycin.
Discovered in bacteria from a soil sample collected on Easter Island (aka Rapa Nui) in the South Pacific, rapamycin is a molecule that prompts cells to perform a kind of spring-clean: clearing out old components and replacing them with new ones.
This process, called autophagy, is also triggered by fasting and has been linked to increased longevity in a wide range of organisms. Scientists have used rapamycin to slow ageing in species as varied as yeast, worms, flies, mice and even tiny primates known as marmosets.
Dogs could be next. That’s the goal of TRIAD (the Test of Rapamycin In Aging Dogs), a clinical trial from the Dog Aging Project aiming to begin in 2026.
The study plans to enrol 580 dogs, treat them with rapamycin for one year and then monitor them for another two years to assess the drug’s long-term effects. (Two smaller, shorter studies have already made sure that it’s safe for dogs and hinted at benefits for older hounds’ heart health).
“I think it’s a better than 50/50 proposition that rapamycin increases lifespan and improves health in dogs,” Kaeberlein says.
“Whether we have the right dose and whether the duration of our clinical trial is enough to show the effect – that’s a different question. But it wouldn’t shock me if, in larger dogs, you could get a 20-plus-per-cent increase in healthy lifespan.”
With rapamycin already showing promise in humans (the drug was recently ranked by scientists among the top five drugs most likely to extend healthy lifespan), it’s easy to see why he’s so optimistic.
Still, it’s the upcoming canine trial that may offer the clearest reason yet to be excited.
Trial and terrier: testing longevity in dogs
Slowing ageing in dogs isn’t just an academic pursuit: almost half of US households have a dog and Americans spend $140bn (£105bn) on their pets annually, meaning there would be plenty of buyers for a drug that could keep them healthy for longer.
That’s why several startups are vying to collar the dog longevity market.
Likely leading the pack is Loyal, which has raised over $150m (£112m) since 2019 and whose experimental drug LOY-002 was provisionally approved by the US Food and Drug Administration (FDA) with a “reasonable expectation of effectiveness."
This approval requires demonstrating that it’s safe, but allows Loyal to take the medication to market while simultaneously running a clinical trial to determine if it works.
Testing a medicine for dogs is quite different from a human drug trial. For a start, the patients are much cuter, as Celine Halioua, founder and CEO of Loyal, jokes. But that’s not its only unique feature.
“Our clinical trial is unlike any other in the sense that we’re not focused on treating a specific disease or ailment, but on extending healthy lifespan overall. It’s the first FDA-concurred trial for a longevity drug for any species,” she says.
Loyal’s study has already enrolled 1,000 dogs, with another 300 on the way. Though the company is keeping exactly what’s in the medicine under wraps for now, its website describes it as a “caloric restriction mimetic”.
This means it tricks the dogs’ cells into thinking that the dog is cutting back on calories.
Dietary restriction has been linked to extending lifespans across the animal kingdom, from worms to monkeys, and a 2007 study reported that eating 25 per cent less could help labradors live 16 per cent longer compared to a normal diet.
Loyal’s hope is that mimicking this process with a drug could create a similar lifespan extension, but without actually needing to feed the dogs less.
Keeping big dogs alive for longer
Loyal’s other drugs, LOY-001 and LOY-003, are designed specifically for big dogs – those over 18kg (40lbs). That’s because they target a key biological difference between large and small breeds: a hormone called insulin-like growth factor 1 (IGF-1).
IGF-1plays a major role in regulating growth and has been linked to both body size and lifespan across the animal kingdom. Bigger dogs produce more of it, which could help explain why they tend to age faster than their smaller counterparts.
By reducing the level of IGF-1 in large dogs, Loyal is hoping the animals will live longer, healthier lives. If that turns out to be true, it could offer valuable clues about how IGF-1 affects ageing in humans too – and whether targeting it might one day help us live longer as well.
Interestingly, scientists have already seen that humans who live past 100 carry unusual variants in their IGF-1 gene, which suggests a possible connection to longevity in people, too.
While concentrating on getting the dog drugs over the line for now, Halioua is keeping one eye on this grand prize: “I believe extending the lives of our best friends is worthy in and of itself,” she says.
“But Loyal’s research could fundamentally change how we think about ageing in general, creating a new category for preventative medicine.”
Read more:
- 6 simple ways to instantly improve your dog's life, according to science
- The (completely adorable) ways dogs know exactly how you're feeling
How old is your dog?
The classic rule for converting human years to dog years is to multiply by seven, so a three-year-old pooch would be 21 dog years old. But we now know that this is an oversimplification.
Researchers at the University of California San Diego measured the biological age of 100 labrador retrievers using an ‘epigenetic age’ DNA test, and compared results of similar tests in humans.
Their results hinted that labradors grow up faster than the seven-year rule would suggest, reaching the equivalent of 31 human years in their first 12 months. Thereafter, things slow down, with a 12-year-old lab being equivalent to a 71-year-old person. That's 13 years less than 12 × 7 = 84.
To calculate your dog’s epigenetic age (this will be most accurate if your dog is a lab) whip out your phone calculator, put it into ‘scientific’ mode (we’re doing science here, after all) and type:
16 × ln(your dog’s age) + 31
Longevity research in the doghouse
Unfortunately, the story of dog ageing isn’t all good news for dogs. Thanks to funding cuts in 2023, The Dog Aging Project has effectively stalled. “Most of the science has come to a halt,” says Kaeberlein.
And it’s not yet clear if more cuts are coming. The current administration has proposed a 44-per-cent cut to the National Institutes of Health (NIH) budget, which could scupper future canine anti-ageing studies.
For Kaeberlein, it’s a massive missed opportunity. “There are 8–10 interventions that are safe enough that they can and should be tested in dogs,” he says.
“If somebody wanted to put between $25m–$50m (approx £18.5m–£37.5m) towards this, you could test 5–10 interventions in dogs and, in five years, figure out which ones slow ageing.”
While we wait for a government, or a rich dog lover, to put up the cash, the Dog Aging Project is still looking for new ‘pack members’ for both its longitudinal study and the rapamycin clinical trial. Just head to dogagingproject.org to sign up your pooch.
Only US-based dogs can enrol for now, but Kaeberlein is “optimistic” that the project will go international “at some point in the future”.
If there’s anything that can unite political factions and, indeed, the world in these tumultuous times, surely more healthy years for our dogs is a strong contender.
Read more:
