A senior Golden Retriever watching as drops of fish oil are added to its food bowl in a bright kitchen

Fish Oil for Dogs: Dosage Chart by Weight, Benefits and Side Effects

October 30, 2026

Quick answer

Fish oil for dogs is dosed by its EPA and DHA content, not by total oil. Controlled dog trials used about 69 mg of combined EPA and DHA per kg a day for arthritis and about 85 mg/kg for itchy skin: roughly 1,380 to 1,700 mg for a 20 kg (44 lb) dog. Stay below the NRC safe upper limit of 370 mg × kg^0.75, and check with your vet first.

Key takeaways

Read EPA + DHA, not "fish oil". A "1,000 mg fish oil" label tells you almost nothing; the active omega-3s are EPA and DHA, and products vary widely.
Joints have the best evidence. Several randomised, placebo-controlled trials in arthritic dogs found better weight bearing, mobility or owner-rated signs with EPA and DHA.
Skin evidence is modest. One 10-week trial in 29 itchy dogs improved scores; guidelines say benefits may take about two months and fish oil is unlikely to work alone.
There is a ceiling. The US National Research Council's safe upper limit is 370 mg of EPA + DHA per kg^0.75, about 3,500 mg a day for a 20 kg dog.
Side effects are usually mild: loose stools, fishy breath, weight gain. Use caution with bleeding disorders, blood thinners, NSAIDs, pancreatitis and diabetes.

Fish oil for dogs dosage chart by weight

There is no single official fish oil dose for dogs. The chart below applies the doses used in two randomised, placebo-controlled dog trials, one for arthritis (69 mg/kg of EPA + DHA a day) and one for allergic skin (85 mg/kg a day), and shows the NRC safe upper limit for comparison. All figures are combined EPA + DHA, not total fish oil.

A fish oil dosage chart by weight for dogs from 5 kg to 50 kg, showing combined EPA and DHA at the arthritis trial dose of 69 mg/kg, the skin trial dose of 85 mg/kg, and the NRC safe upper limit of 370 mg per kg to the power 0.75, for example 1,380 mg, 1,700 mg and about 3,500 mg for a 20 kg dog.

Dog's weight	Joint trial dose (69 mg/kg EPA + DHA)	Skin trial dose (85 mg/kg EPA + DHA)	NRC safe upper limit (370 × kg^0.75)
5 kg (11 lb)	345 mg	425 mg	about 1,240 mg
10 kg (22 lb)	690 mg	850 mg	about 2,080 mg
15 kg (33 lb)	1,035 mg	1,275 mg	about 2,820 mg
20 kg (44 lb)	1,380 mg	1,700 mg	about 3,500 mg
25 kg (55 lb)	1,725 mg	2,125 mg	about 4,140 mg
30 kg (66 lb)	2,070 mg	2,550 mg	about 4,740 mg
40 kg (88 lb)	2,760 mg	3,400 mg	about 5,890 mg
50 kg (110 lb)	3,450 mg	4,250 mg	about 6,960 mg

Where these numbers come from:

Joints: in a 2016 randomised, double-blind trial in 78 dogs with hip or knee arthritis, dogs given an average of 69 mg/kg of EPA + DHA a day for 84 days had significantly less discomfort and lameness than dogs on a placebo oil (Mehler et al.).
Skin: in a 2004 randomised, placebo-controlled trial in 29 dogs with atopic dermatitis, 50 mg/kg EPA plus 35 mg/kg DHA a day (85 mg/kg combined) for 10 weeks improved clinical scores (Mueller et al.).
Wider ranges: a 2025 review in Nutrition Research Reviews found osteoarthritis studies in dogs used about 48 to 100 mg/kg EPA with 20 to 32 mg/kg DHA, and skin studies about 0.99 to 43 mg/kg EPA with 0.66 to 30 mg/kg DHA.
Upper limit: the NRC safe upper limit for dogs is 370 mg of EPA + DHA per kg of metabolic body weight (kg^0.75), as summarised in a 2013 review of omega-3 adverse effects. Board-certified veterinary nutritionists writing in Today's Veterinary Practice give the same worked figure: 3,499 mg for a 20 kg dog.

Three practical rules: start at about half the target dose for the first week or two to let the gut adjust; give it with food; and talk to your vet before starting, especially if your dog takes medication, is pregnant, has a health condition or already eats a skin, joint or kidney diet, because many therapeutic diets already contain fish oil.

EPA and DHA vs total fish oil: how to read the label

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the long-chain omega-3 fatty acids that do the work; the rest of the oil is other fats and calories. Dosing on "total fish oil" can leave a dog under-dosed by several times. The Today's Veterinary Practice authors describe EPA and DHA as the "active ingredient" in pet fish oil supplements and ask manufacturers to state them clearly.

A worked example. Your 20 kg (44 lb) dog has arthritis and your vet agrees to the joint trial dose: 20 × 69 = about 1,380 mg of EPA + DHA a day.

Find the EPA and DHA per capsule or per pump on the label and add them together. Suppose a capsule lists 180 mg EPA and 120 mg DHA: that is 300 mg.
Divide: 1,380 ÷ 300 = about 4.6, so roughly 4 to 5 capsules a day.
Check against the ceiling: 1,380 mg is well under the 20 kg upper limit of about 3,500 mg.

That is why concentrated liquids made for dogs are popular for larger breeds. Whatever the form, the arithmetic is the same: EPA + DHA per dose, times doses, against your dog's target.

A label-reading guide showing that total fish oil is not the dose: add EPA and DHA per capsule, for example 180 mg plus 120 mg equals 300 mg, then divide the dog's daily target, such as 1,380 mg for a 20 kg dog with arthritis, to get about 4 to 5 capsules, and check it is below the safe upper limit of about 3,500 mg.

Does fish oil help dogs with joint pain?

Yes, fish oil has some of the best evidence of any joint supplement for dogs. Several randomised, double-blind, controlled trials in dogs with osteoarthritis have found improvements, measured both by owners and by force plates that record how much weight a dog puts on a sore leg.

In 38 arthritic dogs, a food with 3.5% fish oil omega-3 fatty acids improved peak weight bearing by 5.6% over 90 days, compared with 0.4% on a control food; 82% of the fish oil dogs improved, against 38% of controls (Roush et al., 2010).
In 127 dogs at 18 practices, owners of dogs on a high-omega-3 food reported better ability to rise and play at 6 weeks and to walk at 12 and 24 weeks (Roush et al., 2010).
In 75 dogs with hip arthritis, two omega-3-rich green-lipped mussel oil products (a related marine source, not fish oil) improved weight bearing after 4 and 6 weeks to a similar degree to the anti-inflammatory drug carprofen, while glucosamine with chondroitin did not beat placebo (Kampa et al., 2023).

Expect weeks, not days: most trials measured benefits at 6 to 12 weeks. Fish oil can sit alongside pain medication, weight control and exercise, but it does not replace them for a dog in real pain. For a side-by-side look at fish oil, green-lipped mussel, glucosamine, boswellia and turmeric, see our guide to the best natural joint supplements for dogs.

Does fish oil help dogs' skin and coat?

Fish oil helps some itchy dogs a little, slowly. The 2004 Mueller trial found improved scores in atopic dogs after 10 weeks, and the 2015 international treatment guidelines for canine atopic dermatitis conclude that oral fatty acids might give a small benefit that may not appear before about two months, and are unlikely to work as the only treatment.

For a dull or flaky coat, omega-3 is a sensible, low-risk step once you have ruled out parasites and other causes; our guide to dog dry skin and dandruff covers that work-up. For a dog that is scratching constantly, see the best supplements for dog itching.

Fish oil side effects in dogs

Most dogs tolerate fish oil well; the common side effects are mild and dose-related. VCA Animal Hospitals lists mild stomach upset, a fishy odour, an oily coat, skin flaking and delayed wound healing, and advises stopping and calling your vet for signs of allergy, abnormal bruising or bleeding, pancreatitis, appetite loss or incoordination.

The 2013 review by Lenox and Bauer lists the potential adverse effects to keep in mind at higher doses: altered platelet function, digestive upset, slower wound healing, lipid oxidation, weight gain from the extra calories, altered immune function, effects on blood sugar control, and interactions with drugs.

A fish oil safety card listing common mild side effects (loose stools, fishy breath, oily coat, weight gain) and the dogs who need a vet's go-ahead first: dogs on blood thinners or NSAIDs, dogs with bleeding disorders or upcoming surgery, dogs with a history of pancreatitis, diabetic dogs, and pregnant or nursing dogs.

Ask your vet first if your dog...	Why
Takes blood thinners or NSAIDs (such as carprofen or meloxicam)	VCA lists interactions; omega-3 can affect platelet function.
Has a bleeding disorder or surgery coming up	Possible effects on clotting and wound healing.
Has had pancreatitis	Extra fat is a concern; VCA advises caution.
Is diabetic	Possible effects on glycaemic control.
Is pregnant or nursing, or has diarrhoea	VCA lists these for caution.
Already eats a therapeutic skin, joint or kidney diet	Many contain fish oil; adding more can exceed the safe upper limit.

Does my dog need vitamin E with fish oil?

Usually not as a separate supplement, as long as your dog eats a complete diet and the fish oil is fresh. Omega-3 oils oxidise easily, which is why good products include an antioxidant such as vitamin E (often listed as mixed tocopherols) to protect the oil. In a 12-week study in 15 healthy young dogs, adding menhaden fish oil did not increase markers of lipid peroxidation or change platelet function, and the authors concluded that at that level, extra vitamin E beyond normal dietary amounts was not needed (LeBlanc et al., 2005).

What matters more in practice: buy a product with a stated EPA + DHA content, keep it cool and away from light, and throw it out if it smells rancid. Higher doses for longer periods are a reason to involve your vet, who may adjust the diet's vitamin E.

Can I give my dog human fish oil?

Often, yes, if your vet agrees and it is plain fish oil. Check three things: the EPA + DHA per capsule (so you can dose by the chart), that it contains no xylitol or other sweeteners, which the US FDA warns are dangerous to dogs and can turn up in chewable vitamins and supplements, and that it is not cod liver oil, which also supplies vitamins A and D and is a different product. Gummies and flavoured chews made for people are the riskiest choices.

AyurPet's take

We do not make a fish oil, and we recommend one anyway. For joints, EPA and DHA have stronger dog trials than most of the herbs we love, and an honest wellness brand should say so.

Our advice is simple: ignore the "1,000 mg" on the front, find the EPA and DHA on the back, and dose by your dog's weight against the chart. Most dogs on fish oil for joints are under-dosed, not over-dosed.

When we would tell you to hold off: if your dog has had pancreatitis, has a bleeding problem or surgery booked, or is on blood thinners, or if they already eat a prescription diet rich in fish oil. Ask your vet first.

Where AyurPet fits

Many owners of arthritic dogs use fish oil alongside a joint supplement with different ingredients. If you and your vet want to add a botanical layer, HipOJoint combines glucosamine with boswellia and turmeric, two herbs with their own small dog studies (see our guides to boswellia for dogs and glucosamine for dogs).

Bottle of AyurPet HipOJoint joint and mobility drops for dogs with glucosamine, boswellia and turmeric

HipOJoint joint drops

For dogs whose joints need daily support. Glucosamine, boswellia and turmeric in liquid drops you add to food. It does not contain fish oil, so it can sit alongside an EPA and DHA supplement if your vet agrees. Rated 4.65 stars by customers; follow the dosage on the pack.

See HipOJoint

Frequently asked questions

How much fish oil should I give my dog?

Dose by EPA + DHA, not total oil. Dog trials used about 69 mg/kg a day for arthritis and 85 mg/kg for allergic skin, roughly 690 to 850 mg for a 10 kg (22 lb) dog. Stay under the NRC safe upper limit and agree the dose with your vet.

Can I give my dog too much fish oil?

Yes. Too much can cause diarrhoea, weight gain, slower wound healing and effects on clotting. The NRC safe upper limit is 370 mg of EPA + DHA per kg^0.75, about 2,080 mg a day for a 10 kg dog and 3,500 mg for a 20 kg dog.

How long does fish oil take to work in dogs?

Expect several weeks. Joint trials measured benefits at 6 to 12 weeks, and skin guidelines say benefits may not appear before about two months.

Is salmon oil the same as fish oil for dogs?

Salmon oil is one type of fish oil. What matters is how much EPA and DHA it provides per dose, which varies between products, so dose from the label in the same way.

Is flaxseed oil as good as fish oil for dogs?

Flax provides a plant omega-3 (ALA), not EPA and DHA, so the chart above does not apply to it. Flax oil improved skin scores in one trial, but the joint trials used marine EPA and DHA.

Can I give my dog human fish oil capsules?

Often, if your vet agrees: choose plain fish oil, check the EPA + DHA per capsule, and avoid products with xylitol or other sweeteners, gummies, and cod liver oil.

Should I give fish oil with food?

Yes. Giving it with a meal reduces stomach upset and fishy burps. Start at about half the target dose and build up over a week or two.

How we researched this: Written by the AyurPet research team from 12 sources, including 5 randomised controlled trials in dogs, veterinary reviews and guidelines, listed below. Last reviewed October 2026.

References

Mehler SJ, May LR, King C, Harris WS, Shah Z. 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;109:1-7. doi.org/10.1016/j.plefa.2016.03.015
Mueller RS, Fieseler KV, Fettman MJ, et al. Effect of omega-3 fatty acids on canine atopic dermatitis. Journal of Small Animal Practice. 2004;45(6):293-297. doi.org/10.1111/j.1748-5827.2004.tb00238.x
Vendramini THA, Marchi PH, Olivindo RFG, et al. Exploring the efficacy and optimal dosages of omega-3 supplementation for companion animals. Nutrition Research Reviews. 2025;38(2):859-874. doi.org/10.1017/S0954422425100115
Lenox CE, Bauer JE. Potential adverse effects of omega-3 fatty acids in dogs and cats. Journal of Veterinary Internal Medicine. 2013;27(2):217-226. doi.org/10.1111/jvim.12033
Raditic D, Gaylord L. Fish oil dosing in pet diets and supplements. Today's Veterinary Practice. 2020. todaysveterinarypractice.com
Roush JK, Cross AR, Renberg WC, et al. Evaluation of the effects of dietary supplementation with fish oil omega-3 fatty acids on weight bearing in dogs with osteoarthritis. Journal of the American Veterinary Medical Association. 2010;236(1):67-73. doi.org/10.2460/javma.236.1.67
Roush JK, Dodd CE, Fritsch DA, et al. Multicenter veterinary practice assessment of the effects of omega-3 fatty acids on osteoarthritis in dogs. Journal of the American Veterinary Medical Association. 2010;236(1):59-66. doi.org/10.2460/javma.236.1.59
Kampa N, Kaenkangploo D, Jitpean S, et al. Study of the effectiveness of glucosamine and chondroitin sulfate, marine based fatty acid compounds (PCSO-524 and EAB-277), and carprofen for the treatment of dogs with hip osteoarthritis. Frontiers in Veterinary Science. 2023;10:1033188. PMC9929184
Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Veterinary Research. 2015;11:210. PMC4537558
VCA Animal Hospitals. Fish Oil. Updated 2026. vcahospitals.com
LeBlanc CJ, Bauer JE, Hosgood G, Mauldin GE. Effect of dietary fish oil and vitamin E supplementation on hematologic and serum biochemical analytes and oxidative status in young dogs. Veterinary Therapeutics. 2005;6(4):325-340. PubMed 16550494
US Food and Drug Administration. Paws Off Xylitol; It's Dangerous for Dogs. fda.gov

Before you start: fish oil is a supplement, not a medicine. Check with your vet before giving it, especially if your dog takes medication, is pregnant, has a health condition or eats a prescription diet. For a second opinion, our online vet consultation can help.

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