Omega-3 for dogs: EPA, DHA, sources and evidence

By the PetFishOilGuide editorial team · Updated October 13, 2026 · How we compare

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Omega-3s are fats; the two that dog supplements are measured by are EPA and DHA, found in fish oil, krill oil and algal oil. Compare products by the EPA and DHA milligrams on the label. Research in dogs varies by condition, and your veterinarian should decide whether and how much to give.

"Omega-3" covers several fats, and labels use the term loosely. This page explains the terms, the sources, what has been studied, and where the evidence is thin. It is a source summary, not veterinary advice, and it has not been checked by a veterinarian. Everything we cite is linked.

Is fish oil good for dogs?

It depends on the dog and the reason, and the evidence is stronger for some uses than others. In one randomized trial of 177 dogs with osteoarthritis, a food with about three times the baseline EPA+DHA gave significant but modest improvements in lameness and weight bearing (Fritsch et al., 2010). For other uses, a 2026 review calls the canine evidence limited and scattered. We cannot say fish oil is good for your dog; whether it suits yours, and how much, is a question for your veterinarian. See side effects for what to watch for.

EPA, DHA and the other omega-3s

Three omega-3 fatty acids come up: EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid) and ALA (alpha-linolenic acid). Veterinary dosing guidance is written for EPA and DHA together, in milligrams. In a 2016 article, veterinary nutritionist Cailin Lenox gives the dose she typically uses for dogs as 50 to 75 mg of combined EPA+DHA per kg of body weight (Today's Veterinary Practice). Colorado State's veterinary hospital likewise says doses are based on combined EPA and DHA, not general "fish oil" or "omega 3" labels (CSU).

The practical consequence: "1,000 mg omega-3" on a bottle is not "1,000 mg EPA+DHA." Our dosage page shows how large the gap can be, with examples from real labels, and a calculator for your dog's weight.

Where omega-3 supplements come from

• Fish oil. Oil from fish such as anchovy, sardine, pollock or salmon. The EPA and DHA concentration varies a lot between products. Nordic Naturals Omega-3 Pet (liquid, dogs) lists 621 mg per 2.5 mL, while Nutramax Welactin Canine Softgels (120 ct) lists 255 mg per softgel. See salmon oil for dogs and fish oil vs salmon oil.
• Krill oil. Oil from small crustaceans. Many krill products publish low or no EPA and DHA numbers; see krill oil for dogs.
• Algal oil. Fish get their DHA and EPA from algae in the food chain and do not make them from scratch, as a 2019 PLoS One paper explains (Dahms et al.). Oil from cultured algae is a fish-free route to the same fats. Some dog products use it.
• Plant oils (ALA). Flax and similar oils supply ALA. We could not verify a source that states how efficiently dogs turn ALA into EPA and DHA, so we make no claim either way and do not rank ALA products. Dosing guidance for dogs is written in EPA and DHA.

Dog foods also contain omega-3s from fish meal, whole fish or algae (Raditic and Gaylord, 2020). Those count toward the total, so check the food too.

What omega-3s have been studied for in dogs

We say "studied for" on purpose. A study is not proof that a supplement works for your dog, and we do not claim that omega-3 treats, prevents, or cures any condition.

• Osteoarthritis. In a randomized trial of 177 client-owned dogs with chronic osteoarthritis, dogs eating a food with roughly three times the baseline EPA+DHA showed significant improvements in lameness and weight bearing versus baseline. Dogs on twice the baseline did not. The authors called the improvements modest (Fritsch et al., J Vet Intern Med 2010, PubMed). Read more on our arthritis page.
• Immune function and other uses. A 2026 narrative review of dietary EPA and DHA and immune function in healthy and ill dogs (Barroso, Fonseca and Cabrita, Veterinary and Animal Science) says the canine evidence is still limited and scattered and that better-standardized clinical studies are needed (PubMed 42569613).

We found no source we could verify and quote for coat, shedding or heart claims, so this page does not make them. For life stages and conditions, see our pages on itchy skin, puppies, senior dogs and kidney disease. Ask your vet what applies to your dog.

How much is typical, and how much is too much

For adult dogs, the range published by Lenox is 50 to 75 mg per kg per day. The National Research Council's recommended allowance for adult maintenance is far lower, about 30 mg x kg^0.75 (169 mg for a 10 kg dog), and its safe upper limit is 2,800 mg per 1,000 kcal of diet, about 370 mg x kg^0.75. The limit includes food. Raditic and Gaylord note that therapeutic doses range from 50 up to 220 mg per kg depending on the condition, which is why those are for veterinarians. Our calculator never computes them. The side effects page lists what can happen at higher intakes.

How to read a label

1. Find EPA and DHA in milligrams per serving. If they are missing, you cannot calculate a dose.
2. Check the serving: one softgel, one pump, one teaspoon or one mL.
3. Look for third-party testing for purity and freshness, which CSU recommends, and for the NASC seal if present.
4. Compare products on EPA+DHA per serving, not on bottle size. Our comparison does this, and the methodology page explains how.

Format matters for ease of dosing: liquid, softgel or chews. Some owners wonder about human fish oil, cod liver oil or canned sardines. Brand pages include Welactin, Nordic Naturals, Zesty Paws and Grizzly. Learn about the people behind the site on the about page.

Shopping for a cat? See omega-3 for cats.