Why selenium is a secret weapon in fighting canine ageing

We all know dog ownership is bittersweet because our time with them is limited. They give us so much joy but for what always seems like too short a time. From bouncy puppy to the quiet companion of old age, their lives feel compressed compared to ours. That  too-brief span of a dog’s life is driving scientists, Silicon Valley entrepreneurs and owners alike to ask the same question: how can we give our dogs more healthy years?

In recent years, headlines have been filled with tech moguls investing in radical longevity research for dogs; anti-ageing drugs, genetic tinkering, even cloning. But here’s the thing: many of the most promising avenues for supporting a long, vibrant canine life aren’t hiding in labs. They’re already in nature, quietly doing their work. One of the most intriguing? Selenium.

This humble trace mineral doesn’t get the same spotlight as omega-3 or vitamin D, but emerging science suggests it plays a key role in regulating ageing and much of that comes down to its relationship with a growth hormone called IGF-1.

The science of ageing and IGF-1

IGF-1 stands for insulin-like growth factor 1, and it’s a hormone that does exactly what it sounds like, it drives growth. In puppies and adolescent dogs, IGF-1 is vital. It helps cells divide, tissues develop and muscles and bones grow strong. Without it, dogs couldn’t develop normally.

But here’s the catch, too much IGF-1 later in life is linked to faster ageing. Scientists have noted that large-breed dogs – who have higher circulating levels of IGF-1 – tend to live shorter lives than their smaller cousins. A Chihuahua can sail into its late teens, while a Great Dane might only see eight or nine good years. One key reason? Elevated IGF-1 seems to accelerate cellular wear and tear.

Think of IGF-1 as the throttle pedal for growth. Great when you’re young and revving up the body’s growth; less helpful when what you really need is steady, careful maintenance. High IGF-1 levels in adulthood can encourage excessive cell division, which in turn raises the risk of age-related diseases and shortens overall lifespan.

This isn’t just theory. Research in multiple species – mice, humans and dogs – has shown that lower IGF-1 activity is linked to longer, healthier lives. That’s why scientists are so interested in finding safe, natural ways to help regulate it. And this is where selenium enters the picture.

Where selenium comes in

Selenium is a trace mineral, meaning that dogs only need it in tiny amounts, but its influence is surprisingly powerful. Traditionally, selenium has been studied for its role as an antioxidant defender. It’s a core component of enzymes that mop up free radicals, the unstable molecules that cause oxidative stress and contribute to ageing. That alone would make it valuable.

But what’s particularly exciting is selenium’s emerging role in regulating IGF-1 levels. Studies in both humans and dogs suggest that selenium helps keep IGF-1 in check, especially in adulthood and later life. By nudging IGF-1 back towards balance, selenium may reduce the cellular “overdrive” that accelerates ageing in larger breeds.

In other words, selenium doesn’t stop the healthy development phase – puppies can still grow as nature intended – but it seems to gently ease the pressure as dogs get older, allowing their bodies to focus on repair and resilience rather than unchecked growth.

The result? A potential extension of healthy lifespan, not just in terms of years lived but in quality of those years. Less inflammation, stronger immune defences and possibly a reduced risk of certain age-related diseases.

And here’s the beauty: selenium isn’t some exotic lab-created molecule. It’s found naturally in foods like brewer’s yeast, nuts, seeds, fish, and meat, which means it can be provided to dogs in safe, whole-food forms.

Natural sources of selenium for dogs

Like all minerals, selenium comes in many forms, some more usable than others. Synthetic supplements can deliver selenium in a concentrated hit, but the body doesn’t always absorb it efficiently and excess intake can even become toxic. That’s why natural, food-based sources are the gold standard.

Brewer’s yeast is one of the most effective and safest ways to provide selenium to dogs. Not only is it naturally rich in selenium, but the mineral is present in a form the body recognises and can use more readily. This means the selenium is more bioavailable; it doesn’t just pass through the digestive system unused but is actively taken up by cells and put to work.

Brewer’s yeast also brings along a bonus package: B vitamins for energy metabolism, chromium for blood sugar balance and compounds that can support healthy skin and coat. That makes it a kind of nutrient-dense “carrier,” delivering selenium alongside a team of other helpers.

Other natural sources of selenium for dogs include fish (like salmon or herring), meats, leafy greens and some seeds. But here’s the challenge: selenium levels in food vary depending on the soil it was grown in or the diet of the animal it came from. This inconsistency is one of the reasons a carefully designed supplement can help ensure dogs get enough selenium, in the right form, without relying on chance.

The goal isn’t to flood the system, it’s to provide just enough of this trace mineral to quietly regulate IGF-1, support antioxidant defences and protect cells from premature ageing.

The broader benefits of selenium

Focusing on selenium purely through the lens of IGF-1 means missing a lot of what makes it remarkable. This trace mineral, while needed only in tiny amounts, quietly supports several of the body’s most important systems, each of which plays its part in keeping dogs both healthier and happier as they age.

Take the immune system. A dog’s ability to bounce back from infections, shrug off everyday bugs or recover quickly from stress depends heavily on selenium. It helps immune cells react swiftly and effectively, turning what could be a lingering problem into a brief hiccup. Without enough selenium, that resilience falters, leaving dogs more vulnerable to illness.

Then there’s its role as an antioxidant powerhouse. Selenium forms part of enzymes that act like the body’s clean-up crew, sweeping away the unstable molecules known as free radicals. Left unchecked, free radicals chip away at cells, driving the slow grind of ageing from the inside out. By strengthening these natural defences, selenium helps preserve tissues ranging from joints and skin to the brain and heart, giving dogs a better chance of staying limber, bright-eyed, and mentally sharp.

Perhaps less obvious, but equally important, is selenium’s involvement in thyroid health. The thyroid is the body’s internal metronome, setting the pace for metabolism. When it ticks steadily, energy levels remain balanced, weight is easier to manage and even the condition of the coat reflects this inner harmony. Dogs with steady thyroid function tend to be more energetic and resilient — the kind of dogs who still want to chase the ball long after you’ve tired of throwing it.

Seen together, these threads weave a bigger picture: selenium doesn’t just guard against one pathway of ageing, it strengthens the entire fabric of a dog’s health. A dog with stronger immunity, less oxidative damage and a well-regulated metabolism isn’t just living longer; they’re enjoying those extra years with more vitality and comfort. That, after all, is what longevity should mean; not just adding time but adding good times.

What this means for dog owners

We don’t need to turn to futuristic lab-made drugs or radical interventions to support our pet’s longevity. Sometimes, the most powerful tools are already present in nature, quietly working away in everyday foods. Selenium is one of those tools; not flashy, not exotic, but consistently effective when it comes to helping the body age more gracefully.

By feeding natural, selenium-rich ingredients – like those found in organ meats, seafood, leafy greens or brewer’s yeast – you’re giving your dog a head start in maintaining resilience against the wear and tear of ageing. At its heart, this is what many of us want for our dogs: not just more years, but more good years. And selenium, as one piece of a thoughtful, natural approach, helps tip the odds in their favour.

When it comes to our dogs, ageing can feel like the one opponent we can’t beat. But science is beginning to show us that while we can’t stop the clock, we can influence how gently it ticks. Selenium, through its quiet influence on hormones like IGF-1, its antioxidant role and its support for immunity and metabolism, has emerged as one of nature’s underappreciated allies in this fight.

For dog owners, this is encouraging news. It means we don’t have to place our hopes in experimental drugs or futuristic interventions that seem far removed from the bond we share with our pets. Instead, we can look to natural, whole-food sources; thoughtful nutrition that works in harmony with the body rather than against it.

Of course, selenium is not a cure-all. It’s part of a bigger picture: regular exercise, good vet care, mental stimulation and the kind of love and attention that dogs return a hundredfold. But by making selenium a consistent part of your dog’s diet, you’re stacking the odds towards not just a longer life, but a healthier, happier one.

All our supplements include natural sources of selenium. Check them out here.