Bryan Johnson adds a dog to his longevity routine: Is this his simplest anti-ageing hack yet?

US tech entrepreneur and longevity influencer Bryan Johnson has spent years trying to outsmart ageing. His latest longevity experiment, however, is considerably less high-tech: he got a dog.

The 48-year-old biohacker announced on August 20 that he had adopted a Belgian Malinois puppy named Katara, presenting the new addition as another step in his quest to live longer.

“I got a dog. Dog owners have about a 24% lower risk of dying early. What should I do now?” Johnson wrote on social media along with sharing a photo of his beloved pet and his partner Kate Tolo.

The announcement quickly sparked jokes online, with users wondering whether Johnson had discovered the ultimate anti-ageing hack after years of expensive health interventions.

Why did Bryan Johnson get a dog? 

Johnson's claim refers to research examining the association between dog ownership and mortality. An observational study led by Mount Sinai endocrinologist Dr Caroline Kramer found that dog ownership was associated with a lower risk of death from all causes.

The finding has often been cited as evidence that having a dog may be linked to better longevity. However, it does not prove that owning a dog directly adds years to a person's life.

Researchers have suggested several possible explanations for the association. Dog owners may be more physically active because they regularly walk their pets. Companionship may also reduce loneliness and encourage social interaction, while caring for an animal can provide structure and routine.

For Johnson, who has built his public profile around measuring and optimising almost every aspect of his health, the statistic was apparently compelling enough to add a four-legged variable to his longevity programme.

Social media jokes: How many dogs it takes to live forever? 

Johnson's announcement quickly turned into a social media joke. One of the most popular riffs was the mathematically questionable claim that five dogs would mean a 120% reduction in the risk of dying early.

Others joked that Johnson needed precisely 4.16 dogs to reach a 100% chance of immortality.

The humour played on Johnson's famously quantified approach to health, with followers asking why he had spent years pursuing elaborate anti-ageing interventions when, according to the joke, the solution could simply have been a house full of puppies.

Of course, the 24% figure cannot be multiplied by the number of dogs. The research describes an association between dog ownership and mortality risk; it does not establish that owning additional dogs produces an equivalent reduction in mortality risk.

Johnson's own health battle 

The longevity influencer's pursuit of extreme health optimisation has also had a personal reality check. Earlier this year, Johnson revealed that he had been diagnosed with autoimmune gastritis, a condition in which the immune system attacks cells in the stomach lining.

He said the condition can develop silently over years and causes irreversible damage to the stomach lining. Johnson said doctors eventually identified the problem after years of persistently low ferritin levels, which had been difficult to explain.

The diagnosis underscored a paradox at the heart of Johnson's longevity mission: even someone who tracks his biology obsessively cannot completely control what happens inside the human body. Now, at least, he has Katara for company.

Johnson's obsession with longevity 

The dog is only the latest addition to Johnson's highly publicised effort to slow or reverse biological ageing.

Johnson has experimented with strict diets, exercise regimes, sleep optimisation and extensive health monitoring as part of his broader longevity programme. He has also promoted research into treatments aimed at tackling biological ageing itself.

In 2024, Johnson drew attention to trials involving a proposed longevity drug developed by Telomir Pharmaceuticals. The experimental treatment is designed to target telomeres — protective structures at the ends of chromosomes that tend to shorten as cells divide.

Johnson highlighted claims from research involving ageing German Shepherds, describing the results as potentially significant for future human trials. But such findings remain far from establishing that a treatment can make humans live indefinitely.