Omega-3 for Cats: What the Research Says

Omega-3 for cats mostly means two fats, EPA and DHA, found in oily fish and algae. They're a normal part of a cat's diet, and DHA builds up in a kitten's brain and eyes as they grow.

A complete and balanced cat food is formulated to carry the essential fats a cat needs. Supplements are optional, and your vet should set the amount.

The research is clearer on some points than others. Here's what it shows, where it's thin, and what to check before adding fish oil to the bowl.

What are omega-3s, and which ones matter for cats?

Omega-3s are a family of fats. The Merck Veterinary Manual names three that now count as essential during growth and reproduction in cats: ALA, EPA and DHA.

• ALA (alpha-linolenic acid) comes mainly from plants. Merck names flaxseed oil as the best source.
• EPA and DHA are the long-chain forms. Merck lists oily fish, krill oil and algae oil as the best sources.

The body can turn some ALA into EPA and DHA, but slowly. A 2013 review in the Journal of Veterinary Internal Medicine puts the rate below 10% in people.

A 2024 review in the Journal of Animal Science describes cats as having a limited or null capacity for a key enzyme in that pathway, called delta-6 desaturase.

The 2013 review puts it more cautiously: conversion is believed to be rather limited in dogs and cats. Either way, flaxseed is a weak route to EPA and DHA for a cat.

The same enzyme explains another feline quirk. Merck notes that cats can't readily make arachidonic acid, an omega-6 fat, from other fats. So cats need it ready-made from meat, poultry or eggs, which dogs don't.

What do omega-3s do in a healthy cat?

The best evidence is about growing kittens. In a 1997 study published in the American Journal of Clinical Nutrition, researchers fed mother cats different diets through pregnancy and nursing, then examined the kittens.

Only the diets containing DHA built up high levels of it in the kittens' brains and retinas. Kittens whose mothers ate diets with no DHA or arachidonic acid had slower responses on an eye test at eight weeks.

The researchers concluded that keeping DHA levels up in the nervous system matters for normal retinal function in young cats. Put simply, DHA supports normal retinal function in growing kittens.

It's a striking detail: part of what a kitten sees with is built from the fat in its mother's food.

For skin and coat, the evidence is more general. Merck notes that a shortage of essential fatty acids in general can leave a coat dry, scaly and dull.

The 2024 review credits omega-6 fats with much of the structural work in skin. Evidence specific to omega-3s and the coat of a healthy adult cat is limited in the sources we checked.

What should I know before giving my cat fish oil?

Fish oil deserves the same care as any supplement. The 2013 review in the Journal of Veterinary Internal Medicine set out the possible downsides of omega-3 supplements in dogs and cats.

• Digestive upset. The authors note it is a reported reason for stopping supplements in research studies.
• Calories. Each gram of oil carries about 9 kcal, and a teaspoon about 42 kcal, which can lead to weight gain if nothing else changes.
• Blood clotting. One study the review cites found longer bleeding times in cats after omega-3 supplementation.
• Slower wound healing. Tell your vet about fish oil before any surgery.
• Too much of other nutrients. Fat-soluble vitamins, especially A and D, are the bigger concern because they build up in the body.
• Contaminants and medicine interactions, both listed among the review's concerns.

Fish oils are also prone to oxidation. The review describes vitamin E as protecting these fats from oxidative damage. AAFCO's profiles call for an extra 10 IU of vitamin E for each gram of fish oil per kilogram of food.

Call your vet promptly if your cat:

• has digestive upset or goes off food after starting a supplement
• bruises easily or bleeds longer than usual from a small cut
• is due for surgery while taking fish oil
• takes any daily medicine, before you add a supplement
• is pregnant or nursing and not on a food labeled for growth and reproduction

How much omega-3 does a cat need?

AAFCO's Cat Food Nutrient Profiles set the minimums a food formulated to those profiles must meet. For omega-3s, the numbers only exist for one life stage.

Life stage	ALA minimum	EPA + DHA minimum
Growth and reproduction	0.02% of dry matter	0.012% of dry matter
Adult maintenance	Not determined	Not determined

That second row surprises people. AAFCO's expert panel noted that a case could be made for adult cats needing EPA and DHA, given their low delta-6 desaturase activity, but found no objective data to set an amount.

"Dry matter" means the food with its water taken out. It lets a canned food and a kibble be compared on equal terms.

For individual doses, the honest answer is that there's no standard number for a healthy cat. The 2013 review states that not enough published data exist to set a safe upper limit for cats. Any dose should come from your vet.

Is food enough, or does my cat need a supplement?

For a healthy cat on a complete and balanced food, the veterinary sources don't call for extra. The ASPCA advises that a vitamin or mineral supplement is unnecessary on a complete diet unless a vet finds a specific shortfall.

Cornell Feline Health Center is firmer: supplements can be harmful and should never be given without your vet's approval. The same caution applies to fish oil.

For a kitten, a food formulated to AAFCO's growth profile must meet its omega-3 minimums. Our guide on what to feed a kitten covers how to choose one.

If you'd still like to offer an occasional extra, keep it small and on top of a complete diet. Choolip's Berry Good Milk is one option. It's lactose-free Grade A cow's milk with added lactase, and it contains omega-3 (DHA and EPA).

It also contains taurine, calcium, vitamins D3 and E, CoQ10, glucosamine and cranberry extract. It is not a milk replacer and is never for newborn or orphaned kittens.

For the wider question of whether cats need anything beyond their food, see do cats need vitamins.

Questions new cat parents ask

Does my cat need an omega 3 cat supplement?

Not usually, if the food is complete and balanced. Veterinary sources advise against supplements without your vet's approval, and no safe upper limit has been set for cats.

Can I give my cat flaxseed oil for omega-3?

Flaxseed oil supplies ALA. Cats have limited ability to convert ALA to EPA and DHA, so fish, krill or algae oil are the more direct sources. Ask your vet first.

Do kittens need omega-3?

Yes. AAFCO sets EPA and DHA minimums for growth, and research links DHA to normal retinal function in kittens. A kitten food formulated to AAFCO's growth profile is made to cover it.

Can I use my own fish oil capsules for my cat?

Check with your vet before you do. No safe upper limit has been set for cats, and the 2013 review lists nutrient excess and contaminants among its concerns.

How is omega-3 different from taurine?

Taurine is an amino acid cats must get from food. Our guide to taurine for cats explains why.

Sources

• Merck Veterinary Manual: Nutritional Requirements of Small Animals
• AAFCO Dog and Cat Food Nutrient Profiles (Methods for Substantiating Nutritional Adequacy of Dog and Cat Foods)
• Lenox CE, Bauer JE. Potential adverse effects of omega-3 fatty acids in dogs and cats. Journal of Veterinary Internal Medicine, 2013
• Burron S, et al. The balance of n-6 and n-3 fatty acids in canine, feline, and equine nutrition. Journal of Animal Science, 2024
• Pawlosky RJ, et al. Retinal and brain accretion of long-chain polyunsaturated fatty acids in developing felines. American Journal of Clinical Nutrition, 1997
• ASPCA: Cat Nutrition Tips
• Cornell Feline Health Center: Feeding Your Cat

This article is for general information and is not veterinary advice. Talk to your vet about your own cat — they know the animal in front of them.