🐶 Is Cod Liver Oil Safe for Dogs? Benefits, Risks, and the Right Way to Use It

November 27, 2025

Cod liver oil is a popular supplement known for its rich source of omega-3 fatty acids and vitamins A and D. While it offers many health benefits for humans, many pet owners wonder — can dogs eat cod liver oil safely?

The short answer is yes, dogs can have cod liver oil — but only in small, carefully measured amounts and under a veterinarian’s guidance. Let’s explore its benefits, potential risks, and the correct way to include it in your dog’s diet.

🐕 What Is Cod Liver Oil?

Cod liver oil is derived from the liver tissue of cod fish. It’s packed with omega-3 fatty acids (EPA and DHA), vitamin A, and vitamin D, which are essential nutrients that support joint health, brain function, skin, coat, and overall well-being in dogs.

Unlike regular fish oil (which comes from the body of various oily fish), cod liver oil comes explicitly from the liver — the organ that stores fat-soluble vitamins. This means that cod liver oil has higher concentrations of vitamins A and D, which can be beneficial but also pose risks if overused.

🌟 Key Benefits of Cod Liver Oil for Dogs

When given in the correct dosage, cod liver oil can offer several important health benefits for dogs:

1. Supports Joint and Mobility Health

Omega-3 fatty acids help reduce inflammation and ease stiffness in joints, especially in senior dogs or breeds prone to arthritis. Regular use (in vet-approved amounts) can make your dog more comfortable and active.

2. Promotes Healthy Skin and a Shiny Coat

If your dog suffers from dry, itchy skin or dull fur, cod liver oil can help. The omega-3s nourish skin cells, reduce flakiness, and bring out the natural shine in your dog’s coat.

3. Improves Heart Health

DHA and EPA help lower triglyceride levels and support heart function. For older dogs, a small daily dose can contribute to long-term cardiovascular health.

4. Boosts Brain Development

In puppies, omega-3 fatty acids play a crucial role in the development of the brain and eyes. Supplementing the diet with cod liver oil can enhance learning ability and memory retention in growing dogs.

5. Strengthens the Immune System

The vitamin A and D content in cod liver oil supports a stronger immune response and bone health. Vitamin D, in particular, helps the body absorb calcium and phosphorus, promoting stronger bones and teeth.

⚠️ Possible Side Effects and Risks of Giving Cod Liver Oil to Dogs

Although cod liver oil has many benefits, there are also important risks if it’s given incorrectly or in excess.

1. Vitamin Toxicity

Because cod liver oil contains high levels of vitamin A and D, giving too much can lead to hypervitaminosis — a condition that causes toxicity in the liver, bones, and joints. Symptoms include lethargy, stiffness, loss of appetite, or vomiting.

2. Digestive Upset

Some dogs may experience loose stools, nausea, or a fishy odor in their breath after taking cod liver oil. Always start with a small amount to see how your dog reacts.

3. Interaction with Other Medications

If your dog is currently on supplements or medications—particularly for skin issues or joint pain—adding cod liver oil could lead to overlapping or excessive effects. Always inform your veterinarian before adding any supplement.

4. Not All Dogs Need It

Dogs on high-quality commercial diets already receive adequate omega-3s and vitamins. Excessive supplementation may not be necessary and can even lead to a nutrient imbalance.

🧴 Safe Ways to Add Cod Liver Oil to Your Dog’s Diet

1. Consult Your Veterinarian First

Before starting, always check with your vet. Your veterinarian can recommend the appropriate dosage based on your dog’s age, weight, breed, and overall nutritional needs.

2. Use Pet-Safe Products Only

Select cod liver oil specifically formulated for pets. Human supplements may have added ingredients or doses that are unsafe for dogs.

3. Start Small and Observe

Introduce the oil gradually — mix a few drops with your dog’s meal and observe for any digestive issues that may arise. Increase only if recommended by your vet.

4. Store It Properly

Cod liver oil oxidizes quickly when exposed to heat and light. Store it tightly sealed in a cool, dark place or in the refrigerator to preserve its freshness.

🐾 Recommended Dosage (General Guideline)

While the exact amount depends on your vet’s advice, a general guideline is:

Small dogs (up to 10 kg) – ¼ teaspoon per day
Medium dogs (10–25 kg) – ½ teaspoon per day
Large dogs (25–40 kg) – 1 teaspoon per day

Never exceed the recommended dose. When in doubt, it’s safer to skip a dose than risk over-supplementing.

🦴 Alternatives to Cod Liver Oil

If you’re looking to give your dog the advantages of omega-3s without the potential for vitamin A or D overload, try these safer supplement options instead:

Salmon oil – A rich source of omega-3s with lower vitamin A/D content
Krill oil – Easier to digest and less likely to cause fishy odor
Flaxseed oil – A plant-based source (though less potent in EPA/DHA)

These options may be better suited for dogs that are already getting sufficient vitamins from their regular diet.

💡 Signs You Should Stop Giving Cod Liver Oil

If you notice any of the following, stop supplementation and contact your vet:

Persistent vomiting or diarrhea
Loss of appetite
Stiffness or pain
Dry, brittle nails or skin lesions
Lethargy or behavioral changes

These may indicate that your dog’s body is reacting poorly or experiencing vitamin toxicity.

✅ Final Thoughts

Cod liver oil can be a valuable supplement for dogs, particularly those with joint stiffness, skin issues, or omega-3 fatty acid deficiencies. However, it must be used cautiously and under veterinary guidance due to its high vitamin A and D levels.

If you want your dog to enjoy the benefits of omega-3s safely, always choose vet-approved pet formulations, follow the right dosage, and monitor your dog’s health closely.

A balanced diet, consistent physical activity, and regular veterinary checkups form the true foundation for keeping your dog healthy and happy throughout life.