Omega-3 for Dogs: Benefits, Dose by Weight, and Fish vs Plant-Based Oil

Omega-3 for dogs works by supporting healthy cell membranes and calming the inflammation that drives itchy skin, stiff joints, and other problems. The two most useful forms, EPA and DHA, help the skin barrier, joint comfort, brain and eye development, and heart health. 

Dogs cannot make omega-3s on their own, so they must come from food or supplements. Published trials used about 20 mg of EPA and DHA per kilogram of body weight for coat quality and about 70 mg per kilogram for osteoarthritis, and the right amount for your dog depends on the reason you are giving it.

What Omega-3 Fatty Acids Do in Dogs

Omega-3 fatty acids are essential fats, which means a dog's body cannot produce them and must take them in. Three forms matter:

• EPA (eicosapentaenoic acid) helps the body make compounds that settle inflammation.

• DHA (docosahexaenoic acid) builds brain, eye, and nerve tissue.

• ALA (alpha-linolenic acid) comes from plants, and the body has to convert it into EPA and DHA before it can use it.

The American Kennel Club explains that omega-3s are only part of the picture, since dogs also need omega-6 fatty acids, and that balance between the two supports healthy inflammatory responses. Omega-6s increase inflammation, while the hormones made from omega-3s reduce it. Many commercial diets lean heavily on omega-6 ingredients, which is one reason some dogs benefit from extra omega-3.

Benefits of Omega-3 for Dogs: What the Evidence Shows

The strongest evidence comes from fish-oil studies measuring EPA and DHA. A 2025 review in Nutrition Research Reviews gathered studies of omega-3s in dogs and cats with chronic disease and concluded that the doses reviewed appear effective for atopic dermatitis, osteoarthritis, cardiac disease, high blood fats, and cognitive and behavioral disorders. It also noted that more research is needed for digestive and cancer conditions.

Skin and Coat

Fatty acids are part of the skin barrier, and a shortage can leave skin scaly and the coat dull. A randomized, double-blind, placebo-controlled trial in Prostaglandins, Leukotrienes and Essential Fatty Acids tested fish-oil capsules in 26 dogs with poor-quality coats. The dogs received about 20 mg per kilogram of EPA and DHA daily for 90 days. Their coat and skin scores improved significantly from day 60 and were best at about two months. The benefit lasted about a month after the supplement stopped and then faded. No vomiting or diarrhea was reported. The study was small and partly funded by the supplement's maker, so treat it as a useful signal rather than the final word.

Joints

For osteoarthritis, a randomized, double-blind, placebo-controlled trial by Mehler and colleagues enrolled 78 dogs and used an average of 69 mg of EPA and DHA per kilogram per day. The researchers reported that the blood fatty acid shift correlated with relief of osteoarthritis signs. Omega-3s work best as one part of a plan that also includes weight control, exercise, and veterinary care, and our dog skin and coat health guide covers how the same fatty acids support the skin barrier.

Brain and Cognition

The AKC notes that DHA supports healthy brain and eye development in puppies and may help support cognitive function in older dogs with canine cognitive dysfunction. This is the least settled area. In the 2025 review, a dose could be calculated for only one of five cognition studies, so there is no firm dosing standard for brain health yet.

Omega-3 for Dogs: Dose by Weight

Your vet should set the final dose, because the right amount depends on your dog's weight, diet, and condition. The AKC specifically advises asking your vet instead of relying on package directions. The table below shows published trial doses of EPA and DHA combined, converted into daily amounts, so you can see how they scale. It is not a recommendation.

A few points make the table easier to use:

• Count EPA and DHA only. The numbers refer to EPA plus DHA, not the "total omega-3" printed on many labels, which can include plant ALA.

• Ranges are wide. The 2025 review standardized doses across studies and found osteoarthritis studies used roughly 48 to 100 mg/kg of EPA and 20 to 32 mg/kg of DHA, while dermatology studies generally used lower amounts. These ranges reflect different products and study designs.

• The upper limit matters. A 2020 review in the Journal of the American Veterinary Medical Association notes that the National Research Council's safe upper limit is 370 mg of EPA and DHA per kilogram of body weight raised to the 0.75 power, which is what the last column shows.

Fish Oil vs. Plant-Based Omega-3

Where the omega-3 comes from changes how much of it your dog can use. The AKC states that EPA and DHA from fish oil are more readily used by dogs than plant-based ALA, and its veterinarian points out that ALA conversion is slow, so ALA is not the best choice for an older or ill dog. Here is how the main sources compare:

How Ahiflower Fits In

Plants supply ALA, and the body has to convert ALA into stearidonic acid (SDA) before it can become EPA. That first step depends on an enzyme called delta-6-desaturase, which is slow and limits how much EPA results. Ahiflower oil, from the seed of Buglossoides arvensis, contains about 20 percent SDA, so it skips that bottleneck. A phase I randomized trial in healthy adults found that Ahiflower raised tissue long-chain omega-3 content more than flaxseed oil did.

That is human data. We could not find a published trial of Ahiflower in dogs, so it is fair to say the case for plant-based omega-3 in dogs rests on mechanism and human research rather than direct canine trials. Ahiflower also contains GLA, an omega-6 fatty acid linked to anti-inflammatory metabolites. You can read more on our Ahiflower page.

WagWell's labels list total omega-3, not EPA and DHA, so the dose table above cannot be used to dose them. They work best as everyday support rather than as a stand-in for a measured therapeutic dose. If your dog has osteoarthritis or another condition, ask your vet whether you need a product with a defined EPA and DHA content.

• Ahiflower Omega Oil is a pump topper. The label recommends one pump for dogs under 60 pounds and two for dogs over 60 pounds.

• Ahiflower Omega Chews are a daily soft chew dosed by weight, with one chew for dogs up to 25 pounds. They contain natural poultry flavor, so check with your vet if your dog has a poultry sensitivity.

Side Effects and Safety

The AKC lists diarrhea, vomiting, excess gas, and fishy-smelling breath or skin as possible side effects. Less common risks include weight gain, pancreatitis, delayed wound healing, allergic reactions, and, in rare cases, increased bleeding. Start with a small amount and increase slowly, as your vet directs. Stop the supplement and call your vet if you see any of these signs.

Tell your vet before surgery or if your dog takes medication, since omega-3s can affect bleeding and may interact with other drugs. Store oils away from heat, light, and air, because oxidation turns oil rancid and can upset the stomach. Human supplements are not a safe shortcut, since they may contain ingredients that are unsafe for dogs.

How Long Until You See Results?

Plan on weeks, not days. In the coat-quality trial, scores improved significantly from about day 60 and peaked around two months. Osteoarthritis trials, such as the 78-dog study, ran for about 12 weeks. In that trial the coat benefit held for about a month after the supplement stopped and then began to fade, so consistency matters.

How to Choose an Omega-3 Supplement

• Check EPA and DHA content. Look for milligrams of each, not only a "total omega-3" figure.

• Know the form. The AKC describes natural triglyceride oil as the least processed and easiest to absorb, ethyl ester oil as concentrated, and synthetic triglyceride oil as generally the least absorbable.

• Look for quality seals. Independent certifications and well-sourced oils matter, and smaller cold-water fish tend to carry fewer contaminants.

• Choose a dog-specific product. Pick a product made for dogs, and ask your vet about dose.

Omega-3 for Dogs FAQs

What does omega-3 do for dogs?

Omega-3s support the skin barrier, coat quality, joint comfort, brain and eye health, and heart health. They work by building cell membranes and helping the body settle inflammation.

How much omega-3 should I give my dog?

It depends on the reason, your dog's weight, and the product. Trials have used about 20 mg of EPA and DHA per kilogram for coat quality and about 70 mg per kilogram for osteoarthritis, so ask your vet to set the amount.

Is plant-based omega-3 as good as fish oil for dogs?

Fish oil supplies EPA and DHA directly, and the AKC says dogs use them more readily than plant ALA. Ahiflower provides SDA, which skips the slowest conversion step, but it has not been tested in dogs the way fish oil has.

Can I give my dog human fish oil?

The AKC advises against it, because human products may contain ingredients that are unsafe for dogs and are dosed for people. Choose a supplement made for dogs.

How long does omega-3 take to work in dogs?

Coat and skin changes appeared at about two months in a randomized trial. Osteoarthritis trials ran for roughly 12 weeks.

Can puppies have omega-3?

Yes. The AKC notes that DHA supports healthy brain and eye development in puppies. Ask your vet about the right product and amount.

What are the side effects of omega-3 for dogs?

The most common are loose stools, vomiting, gas, and fishy-smelling breath or skin. Rare risks include pancreatitis, delayed wound healing, and increased bleeding.

Choosing Omega-3 With Your Vet

Omega-3 is one of the better-studied supplements for dogs, and the research is clearest for skin, coat, and joints. The source and the dose matter as much as the label claims. Ask your vet which form suits your dog, count EPA and DHA when you compare products, and give it a couple of months before you judge the results.

Sources:

American Kennel Club. "Fish Oil for Dogs: What to Know."

Vendramini THA et al. "Exploring the efficacy and optimal dosages of omega-3 supplementation for companion animals." Nutrition Research Reviews, 2025.

Combarros D et al. "A prospective, randomized, double blind, placebo-controlled evaluation of the effects of an n-3 essential fatty acids supplement (Agepi ω3) on clinical signs, and fatty acid concentrations in the erythrocyte membrane, hair shafts and skin surface of dogs with poor quality coats." Prostaglandins, Leukotrienes and Essential Fatty Acids, 2020.

Mehler SJ et al. "A prospective, randomized, double blind, placebo-controlled evaluation of the effects of eicosapentaenoic acid and docosahexaenoic acid on the clinical signs and erythrocyte membrane polyunsaturated fatty acid concentrations in dogs with osteoarthritis." Prostaglandins, Leukotrienes and Essential Fatty Acids, 2016.

"Consumption of Buglossoides arvensis seed oil is safe and increases tissue long-chain n-3 fatty acid content more than flax seed oil: results of a phase I randomised clinical trial."

"Nutrition and nutraceuticals in the changing management of osteoarthritis for dogs and cats." Journal of the American Veterinary Medical Association, 2020.