Omega-3 fatty acids from fish oil are among the most popular supplements for dogs. They’re used for joints, skin and coat, and other conditions. Nordic Naturals and Welactin are two well-known options. This review looks at what fish oil can do, the evidence and what to consider.
Verdict at a Glance: Fish oil supplements such as Nordic Naturals and Welactin provide EPA and DHA, the omega-3s with the most research in dogs. There’s reasonable evidence for some uses, especially arthritis. Dosing should be based on EPA and DHA content, not total fish oil, and your vet should help set the amount. Side effects can include stomach upset and fishy breath.
At a Glance
| Feature | Details |
|---|---|
| Main omega-3s | EPA and DHA |
| Forms | Liquids, capsules and soft chews |
| Brands | Nordic Naturals, Welactin and others |
| Uses | Joint health, skin and coat, and other vet-guided uses |
| Storage | Cool, dark place; some liquids need refrigeration |
What It Is and How It Works
EPA and DHA are omega-3 fatty acids found mainly in fish and marine oils. They have anti-inflammatory effects.
Research supports omega-3s for dogs with osteoarthritis, and several prescription joint diets are enriched with them. Evidence for skin and coat benefits is more mixed but promising for some dogs.
Dosing should be based on EPA and DHA, not the total amount of oil. Labels vary widely in how much EPA and DHA they contain. Your vet can calculate a dose based on your dog’s weight and condition. See arthritis in dogs and why is my dog itching.
Pros and Cons
| Pros | Cons |
|---|---|
| Research support for arthritis | Dosing can be confusing |
| May help skin and coat | Possible stomach upset |
| Several forms | Fishy smell |
| Reputable brands available | Adds calories |
| Easy to add to food |
A Broader Plan for Joint Health
Supplements are only one part of caring for a dog’s joints. Vets often focus first on:
| Approach | Why it matters |
|---|---|
| Healthy body weight | Extra weight puts more stress on joints and is one of the biggest factors in arthritis pain |
| Regular, moderate exercise | Keeps muscles strong and joints moving |
| Prescription pain relief | NSAIDs and other medications can greatly improve comfort |
| Physical therapy | Builds strength and range of motion |
| Home changes | Rugs on slippery floors, ramps and supportive beds |
Supplements are not regulated like drugs in the United States. Look for brands that follow quality standards, such as those carrying the National Animal Supplement Council (NASC) seal. See arthritis in dogs and senior dog care.
Safety Notes and Possible Side Effects
- Common side effects include stomach upset, diarrhea and fishy breath.
- High doses may affect blood clotting, so tell your vet before surgery.
- Fish oil adds calories.
- Oxidized (rancid) oil may be harmful; store properly.
- Ask your vet before using with other supplements or medications.
Things to Consider Before Buying
- Ask your vet for an EPA and DHA dose.
- Check the label for EPA and DHA content.
- Start with a lower dose and increase gradually.
- Store properly.
- Watch for side effects.
Tips for Using It
- Give with meals.
- Refrigerate liquid oils after opening if the label says so.
- Smell the oil occasionally; rancid oil smells sharp or sour.
Who It Suits
| Good fit if… | Consider something else if… |
|---|---|
| Your dog has arthritis | Your dog has a bleeding disorder or upcoming surgery (ask your vet) |
| Your vet recommends omega-3s | Your dog has pancreatitis history (ask your vet) |
| Your dog has dry skin or a dull coat |
Alternatives to Consider
| Option | How it differs |
|---|---|
| Prescription joint diets | Built-in omega-3s |
| Joint supplements | Glucosamine and chondroitin |
| Krill oil | Another omega-3 source |
When to Call Your Vet
Contact your vet if:
- Your dog has diarrhea or vomiting after starting fish oil
- Your dog bruises easily or has bleeding
- Your dog’s skin or joint problems worsen
Frequently Asked Questions
Does fish oil help dogs with arthritis?
There’s research support for omega-3s in dogs with osteoarthritis. Ask your vet about dosing.
How much fish oil should I give my dog?
Base the dose on EPA and DHA content and your dog’s weight. Your vet can calculate it.
What’s the difference between Nordic Naturals and Welactin?
Both are fish oil products for dogs. Compare EPA and DHA per serving, form and cost.
Can fish oil cause side effects?
Yes. Stomach upset, diarrhea and fishy breath are common. Start slowly.
Can I give my dog human fish oil?
Some vets use human products, but check ingredients and dosing with your vet. Avoid added xylitol or flavorings.
How should I store fish oil?
In a cool, dark place. Refrigerate liquids after opening if the label says so.
Does fish oil help itchy skin?
It may help some dogs. Itching has many causes, so see your vet.
How long does fish oil take to work?
Many vets suggest several weeks to a few months.
Pet Health Man is independent and isn’t paid by the brands we review. Product formulas, specifications and prices change, so check the current label or the manufacturer’s information before you buy.
This article is for general information only and isn’t a substitute for professional veterinary advice. If you’re worried about your pet’s health, contact your veterinarian or an emergency animal hospital.
