Omega-3 for Dogs

Omega-3 is the single most useful thing most owners can add to a bowl, and also the one most commonly done wrong — because the number on the bag rarely means what people think it means.

The ratio is the whole story

Omega-6 and omega-3 compete for the same enzymes. Feed a surplus of omega-6 and the body converts it into inflammatory signalling molecules constantly, with nothing to fight. Feed more omega-3 and that same machinery produces a much weaker signal.

• Target: 5:1 omega-6 to omega-3 or lower. Lower is better.
• Most kibble runs 15:1 to 30:1. That's the baseline most dogs live at.

Arachidonic acid (AA), plainly: it's the omega-6 the body turns into inflammatory signals. It's necessary — it's how infection gets fought and wounds heal. The problem is surplus. Reducing it is not risky: adult dogs synthesise their own AA from linoleic acid, so it isn't a dietary requirement the way it is for cats.

⚠️ Ratios are flattered by ALA

This is the part almost nobody checks. There are three omega-3s and they are not interchangeable:

• ALA — plant-source (flaxseed, chia). Dogs convert it to EPA/DHA at a very poor rate, often cited in the low single digits.
• EPA — marine. The anti-inflammatory workhorse.
• DHA — marine. Brain, eyes, nerves.

A food can advertise a beautiful ratio that's almost entirely flaxseed. On marine omega-3 alone the same food might be four or five times worse. When you see a good ratio, look for where the omega-3 actually comes from — and if the label just says "flaxseed," treat the number with suspicion.

What it's actually for

• Inflammation — the root driver behind lipomas, arthritis and chronic skin problems
• Joints — in one arthritis study, the large majority of dogs improved weight-bearing
• Skin and coat — usually the first visible change, within weeks
• Heart — supports rhythm and cardiac function
• Brain — DHA for cognition in seniors and development in puppies
• Kidneys — slows progression in chronic kidney disease

Sources, ranked

Whole-food first.

• Sardines in water — the best value in dog nutrition. Small fish, low on the food chain, so low mercury. Half a can for a medium dog.
• Mackerel, anchovies, wild salmon — same logic
• Green lipped mussel — contains ETA, an omega-3 that inhibits both the COX and LOX inflammatory pathways. Fish oil's EPA works mainly on COX alone. That's a genuine second mechanism, which is why GLM and fish oil stack rather than duplicate.

Supplemented.

• Fish oil — the reliable way to hit a therapeutic dose. Start low.
• Krill oil — phospholipid-bound, well absorbed, more expensive
• Algae oil — the vegetarian source of true EPA/DHA; the only plant source that skips the conversion problem

Not really omega-3 for practical purposes.

• Flaxseed, chia, hemp — ALA only. Fine as food, not a substitute for marine sources.

Dosing

Roughly, on combined EPA + DHA, not total fish oil:

• General health: ~50–75 mg per kg of body weight
• Therapeutic (arthritis, skin, lipomas): ~100–150 mg per kg

For a 75 lb (34 kg) dog that's roughly 1,700 mg/day general and up to ~3,400 mg/day therapeutic. Read the label for EPA+DHA content per serving — a "1000 mg fish oil" capsule often contains only 300 mg of actual EPA+DHA.

Start at half and build up over two weeks. Too much too fast means loose stool, and people wrongly conclude the dog can't tolerate fish oil.

Safety and storage

Oxidation is the real risk, not the oil. Omega-3s are fragile. Rancid fish oil is pro-inflammatory — the exact opposite of what you bought it for.

• Buy small bottles, keep them in the fridge, use within a couple of months of opening
• If it smells strongly fishy or sharp, throw it out
• Look for a product with vitamin E added as an antioxidant
• Vitamin E requirement rises with polyunsaturated fat intake — AAFCO scales it at roughly +0.6 IU per gram of PUFA. High omega-3 intake with low vitamin E is the combination to avoid.

Fish oil is not a blood thinner — a common piece of received wisdom that doesn't hold up. A randomised trial of over 1,500 cardiac surgery patients on 6.5–8 g EPA+DHA found bleeding was not increased, and those patients needed fewer transfusions.

Watch calories and fat. Oil is dense. In a dog with a history of pancreatitis, or one already on a high-fat diet, add it deliberately rather than on top of everything else.