Dog Tips

This Nutrient-Rich Oil Is a Staple for Canine Wellness

Discover how one simple marine oil can support your dog's joints, skin, heart, and more naturally and effectively.

Reviewed by Dr. Arielle Walton

Feb 17, 2026 • 6 min read

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STORY AT-A-GLANCE

Cod liver oil’s anti-inflammatory omega-3s help relieve stiffness and pain in aging dogs, promoting easier movement and reducing the need for pain medications over time
This nutrient-rich oil soothes dry, itchy skin and helps balance inflammatory responses, leaving your dog with a softer, glossier, more comfortable coat
Omega-3s in cod liver oil support heart rhythm and brain function, aiding in mental focus, reducing anxiety, and promoting calmer behavior in both young and senior dogs
While beneficial, cod liver oil need to be dosed carefully to avoid vitamin toxicity. Always consult your vet and give it daily for consistent, long-term wellness benefits
Krill oil, another marine oil, also delivers fast-absorbing omega-3s and natural antioxidants like astaxanthin, making it a gentle, effective alternative for boosting your dog’s skin, joints, heart, and immune health

If you’re always looking for simple, natural ways to support your dog’s long-term health, you’re not alone. Many pet parents want to do more than just meet basic needs — they want their dog to feel comfortable, energetic, and resilient at every stage of life. One supplement that has stood the test of time in canine wellness is cod liver oil.

This nutrient-rich oil has been used for decades to support everything from joint comfort to skin health. While it may sound old-fashioned, modern research continues to shed light on why cod liver oil remains a staple for many dogs today. When used thoughtfully and in appropriate amounts, it can provide broad, whole-body support that goes far beyond a shiny coat.

What Is Cod Liver Oil?

Cod liver oil is exactly what it sounds like: oil extracted from the liver of cod fish. It’s a natural source of omega-3 fatty acids, specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), as well as vitamins A and D.^1,2

Unlike regular fish oil that can come from a variety of fish parts, cod liver oil is drawn only from the liver, making it especially rich in these specific nutrients. That’s both a benefit and a reason to be cautious — it’s powerful, and that means proper dosing is key.

The Many Benefits of Cod Liver Oil for Dogs

Cod liver oil isn’t just a trendy supplement; it’s a multipurpose health booster that supports several key areas of your dog’s well-being.

Soothes joint pain and stiffness — One of the most well-known benefits of cod liver oil is its ability to ease joint pain, especially in older dogs or those with arthritis.

Omega-3s found in cod liver oil help reduce inflammation in the joints. Studies show that dogs taking cod liver oil experience improved mobility and less stiffness, with some even needing fewer pain medications over time.³

In one study, dogs with arthritis were divided into two groups. One group received a regular diet, and the other a diet enriched with cod liver oil. After 13 weeks, the cod liver oil group showed clear improvements in movement and quality of life.⁴

Another experiment found that cod liver oil actually protected cartilage from damage in lab tests, making it a powerful tool in slowing the progression of arthritis.
Improves skin and coat health — Is your dog constantly itching, licking, or suffering from flaky skin? Cod liver oil may help. Omega-3s help balance the body’s inflammatory responses. In dogs with dry, itchy, or inflamed skin, this balance is often off, especially if they’re eating food heavy in omega-6s (like most kibble).

Supplementing with cod liver oil can help reduce inflammation and soothe skin problems, whether caused by allergies, genetics, or environmental factors. Many dog owners also report shinier, softer coats within weeks of starting a fish oil supplement.^5,6
Boosts heart health — Heart disease doesn’t just affect people; it can strike dogs, too. Fortunately, omega-3s can offer some protection.

Cod liver oil helps by reducing harmful fats in the blood (such as triglycerides), supporting healthy blood flow, and reducing inflammation in the arteries. Some studies even found that dogs with irregular heartbeats (arrhythmias) saw improvements after just six weeks on cod liver oil.^7,8
Supports brain function and behavior — Did you know that cod liver oil might help your dog stay mentally sharp and even reduce aggressive behavior? Studies have shown that omega-3s can support brain development in puppies and help keep senior dogs mentally sharp. In humans, these same nutrients help with memory, focus, and mood — and dogs may benefit in similar ways.

In one study, aggressive male German Shepherds were found to have lower omega-3 levels than more balanced dogs. This study led scientists to believe that healthy omega-3 levels may help reduce anxiety and tension.⁹
Promotes a healthy immune system — Cod liver oil provides a double punch: omega-3s to fight inflammation and vitamins A and D to support immune health. Vitamin A helps keep your dog’s skin, eyes, and mucous membranes (like the nose and lungs) in good shape. It’s a front-line defender against infections.

Vitamin D, on the other hand, plays a significant role in regulating the immune system. It’s essential if your dog doesn’t get much sunlight, which is common during long winters or for dogs who mostly stay indoors.
May offer cancer-fighting support — Emerging research shows that omega-3s might play a role in slowing the growth of cancer cells, reducing inflammation, and even helping the body better tolerate treatments like chemotherapy.¹⁰

That said, experts warn that cod liver oil isn’t a cure or treatment for cancer, and the research is still developing. But as part of an overall wellness plan, it may offer gentle, supportive benefits.

When Cod Liver Oil Might Not Be the Best Fit

As wonderful as cod liver oil can be, it’s not for every dog. Because it’s packed with fat-soluble vitamins (especially A and D), too much can be harmful. Here are a few reasons to be cautious:

Risk of vitamin toxicity — Too much vitamin A can lead to weight loss, peeling skin, or congenital disabilities in pregnant dogs. Too much vitamin D can cause vomiting, thirst, and dangerous calcium levels.¹¹
Bleeding risks — Omega-3s can thin the blood, which might increase bleeding during surgery or worsen certain medical conditions.
Medication conflicts — Cod liver oil might interact with drugs for diabetes, high blood pressure, or blood thinners.

When in doubt, check with your veterinarian. They can help you decide if cod liver oil is a safe and smart choice for your pup.

How to Safely Give Cod Liver Oil to Your Dog

If you’ve decided to give cod liver oil a try, here are some tips to do it safely and effectively:

Choose the right product — You can find cod liver oil in liquid or capsule form. Some are made for pets, while others are meant for humans. Either is fine, but always check the label and make sure it doesn’t contain extra ingredients such as flavors or preservatives, that aren’t safe for dogs.

Look for products that list EPA and DHA amounts clearly, and avoid any with added synthetic vitamins unless your vet recommends them.
Use the correct dose — Dosing is everything when it comes to cod liver oil. Giving too much can lead to stomach upset, vomiting, or worse.

Some general guidelines suggest 20 to 55 mg of combined EPA and DHA per pound of body weight, but your vet can provide a personalized recommendation. Start low and go slow. If your dog does well, you can adjust the amount over time.
Make it a daily habit — Cod liver oil works best when given daily, not occasionally. Studies show that the benefits of EPA build up over time, often reaching full strength after 28 days.¹² You can mix it with your dog’s food, squirt it into a treat, or offer a capsule hidden in (xylitol-free) peanut butter.

Cod liver oil isn’t a magic remedy, but it is a time-tested, nutrient-rich supplement that can support your dog’s wellness in many ways.

From smoother joints and shinier coats to stronger hearts and calmer minds, the benefits are broad and backed by promising research. Just remember: Use it wisely, dose carefully, and always loop in your vet.

Krill Oil — Another Marine Powerhouse for Canine Health

Just like cod liver oil, krill oil is a marine-based supplement rich in omega-3 fatty acids — but it brings a few special perks of its own. Krill are tiny shrimp-like sea creatures harvested from cold ocean waters, and their oil is packed with the same EPA and DHA fats that benefit your dog’s body in many ways. Importantly, krill oil delivers these fats in a form that’s easier for your dog’s cells to absorb.

The omega-3s in krill oil are carried on phospholipids, which help them move smoothly into your dog’s cells. This means your pup may benefit more from a smaller amount than from traditional fish oils. Krill oil also naturally contains astaxanthin, a potent antioxidant that helps protect your dog’s cells from everyday stress.

Just like with cod liver oil, look for high-quality krill oil sources labeled for pets and ideally sustainably harvested from clean waters. Always introduce it slowly and consult your vet to determine the correct dose for your dog’s size and health needs.