Omega-3s are a family of polyunsaturated fatty acids, and 3 members named in dog nutrition are EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid) and ALA (alpha-linolenic acid).1 Dogs get EPA and DHA from their diet, and fish oil is a common source.1
What makes a fatty acid essential for dogs?
A fatty acid is called essential when the body cannot make enough of it, so it has to come from food. Omega-3s such as EPA, DHA and ALA are discussed in dog nutrition on that basis.1
Dogs can turn ALA into EPA and DHA, but only at a quite limited rate, so EPA and DHA should come from the diet itself.1
Where do EPA and DHA come from?
EPA and DHA can come from fish oil, an efficient source of both.1 Commercial dog food also usually contains some ALA.1
Do puppies need DHA?
Yes, puppies need DHA, an omega-3 fatty acid, to support brain development, along with more protein for growing muscles and calcium and phosphorus for growing bones.2 High-quality puppy food supplies these nutrients, and a vet can advise on the right diet for a growing dog.2
How are omega-3s different from omega-6s?
Omega-3s and omega-6s are 2 separate families of polyunsaturated fatty acids, and dogs need some of each in their diet.1 Linoleic acid is an omega-6 that commercial dog food usually contains.1
Arachidonic acid is another omega-6, and a dog's body makes it from linoleic acid.1 In the same way, ALA is the starting point for EPA and DHA.1 Both conversions use the same enzymes, so turning ALA into EPA competes with turning linoleic acid into arachidonic acid.1
| Fatty acid | Family | Where it comes up | Short form in research |
|---|---|---|---|
| ALA | Omega‑3 | Starting point for EPA and DHA; dogs convert only a little | 18:3 n‑3 |
| EPA | Omega‑3 | Fish oil | 20:5 n‑3 |
| DHA | Omega‑3 | Fish oil | 22:6 n‑3 |
| Linoleic acid | Omega‑6 | Commercial dog food usually contains it | 18:2 n‑6 |
| Arachidonic acid | Omega‑6 | Made from linoleic acid | 20:4 n‑6 |
How do omega-3s show up on a label?
Omega-3 sources show up on a label by name in the ingredient list.3 Under rules from the US Food and Drug Administration (FDA), ingredients must be listed by their common or usual name, in descending order of predominance by weight.3 That order counts water, so the most prominent ingredient by weight, including water, is listed first.4
To sort what you find, work through these 3 steps:
- Find the ingredient list, since federal labeling rules require a listing of all ingredients.3
- Look for fish oil, a source of EPA and DHA.1
- Note where fish oil sits in the list, since ingredients run from most to least by weight, water included.3,4
The ingredient list is only part of the label. For the rest, from the purpose statement to the lot number, see our part-by-part walkthrough of a supplement label.
If a daily chew is part of your plan, our guide to building a daily supplement routine covers how to tie it to mealtime.
For more plain-English explainers, browse more Learn guides.
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Frequently asked questions.
Does my dog need an omega-3 supplement?
Not necessarily. Dr. John Bauer of Texas A&M says healthy animals on complete and balanced diets should not need supplements, and that fish oil may have a place in consultation with a veterinarian.5 Check your dog's food label and ask your vet before adding anything.
Is fish oil safe for dogs?
Cornell's Riney Canine Health Center describes omega-3 fatty acids as generally safe, with fish oil as the usual source.6 It advises checking that a product does not contain heavy metal contamination and following the directions closely, since too much could lead to loose stools.6
What is the difference between EPA, DHA and ALA?
All three are omega-3 fatty acids. EPA and DHA are found in fish oil, while ALA is the starting point dogs convert into EPA and DHA, but only at a limited rate.1
Do puppies need DHA?
Yes. Texas A&M lists DHA among the nutrients puppies need to support brain development.2
How do I know if a food or chew contains fish oil?
Look for it by name in the ingredient list, which runs from most to least by weight.3
Sources.
- Pellegrino FJ, Corrada Y, Picco SJ, Relling AE, Risso A. Association between dietary polyunsaturated fatty acids and their concentration in blood plasma, red blood cell, and semen of dogs. Open Veterinary Journal, 2023.
- Texas A&M School of Veterinary Medicine & Biomedical Sciences. The Puppy Timeline: Physical and Mental Changes. Texas A&M University, 2023.
- US Food and Drug Administration, Center for Veterinary Medicine. Animal Food Labeling and Pet Food Claims. FDA, 2026.
- Croney CC, Croney Research Group, Purdue University. Understanding Dog Food Labels. Purdue University, 2023.
- Texas A&M School of Veterinary Medicine & Biomedical Sciences. The Importance of Supplements for Your Pets. Texas A&M University, Pet Talk.
- Cornell University College of Veterinary Medicine, Riney Canine Health Center. Diets to boost immunity. Cornell University.
