Supplements for senior dogs, starting with omega-3s and probiotics

What joint supplements may help senior dogs?

Omega-3 fatty acids from fish oil may help support joint comfort in older dogs. A 2010 randomized, double-blind, controlled trial published in the Journal of the American Veterinary Medical Association enrolled 127 dogs with osteoarthritis and fed them either a standard diet or one enriched with omega-3 fatty acids. Dogs on the omega-3 diet showed improvement in weight-bearing and veterinary assessments of pain over the 24-week study period.

The trial used a food formulation with a 31-fold increase in omega-3 content. Fish oil contains EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the two omega-3 fatty acids most studied for joint and inflammatory conditions in dogs.

CBD has also been studied for osteoarthritis. A 2020 randomized, double-blind, placebo-controlled study of 20 dogs published in Pain found a decrease in pain and an increase in activity, according to owner assessments and veterinary pain scores. A 2023 systematic review and meta-analysis of multiple CBD trials for canine osteoarthritis published in Frontiers in Veterinary Science found evidence of efficacy, though the authors noted limitations in study quality, small sample sizes, and variability in CBD formulations.

A 2025 study of CBD for post-surgical pain in dogs found no benefit beyond standard pain medication, suggesting that CBD's usefulness may be context-dependent.

Glucosamine and chondroitin, once among the most widely recommended joint supplements, have not held up well in recent research. A 2023 prospective, block-randomized, double-blind, placebo-controlled trial of 75 dogs with hip osteoarthritis published in Frontiers in Veterinary Science tested glucosamine and chondroitin sulfate against placebo and found no significant improvement at weeks four or six. A 2022 systematic review and meta-analysis published in Frontiers in Veterinary Science concluded that these supplements showed a "very marked non-effect" and that they "should no longer be recommended for pain management in canine osteoarthritis."

How much omega-3 should a dog get?

The 2010 JAVMA trial used a food formulation rather than a standalone supplement, which makes direct dose comparisons difficult, but the omega-3 content was 31 times higher than in standard diets.

Choose a fish oil product that lists the EPA and DHA content on the label, not just total fish oil. Products vary widely in their concentration of these two fatty acids. Check with your vet for a dose appropriate to your dog's weight, health status, and current diet, especially if your dog takes blood-thinning medications or has a clotting disorder.

What digestive supplements may help older dogs?

Probiotics may help maintain digestive health and support immune function in senior dogs. According to Cornell University College of Veterinary Medicine, 70 to 90 percent of the immune system resides in the gut, where beneficial bacteria help protect against pathogens and support nutrient absorption.

A 2019 systematic review of probiotics in dogs, published in the Journal of Veterinary Internal Medicine, examined multiple studies and found some evidence for benefit in preventing or managing gastrointestinal conditions, though the review noted wide variation in study designs, probiotic strains, and doses. Veterinarians often consider probiotics for dogs on long-term medications such as antibiotics or nonsteroidal anti-inflammatory drugs, and for dogs recovering from illness or experiencing stress.

No single probiotic strain or dose has been established as standard for senior dogs. Common strains studied in dogs include Lactobacillus and Enterococcus species. Talk to your vet about which product and dose are appropriate for your dog.

Can CBD help senior dogs with pain or stiffness?

CBD has been studied in multiple trials for osteoarthritis pain in dogs. A 2020 randomized, double-blind, placebo-controlled study published in Pain enrolled 20 dogs with osteoarthritis. Dogs receiving CBD showed a decrease in pain and an increase in activity according to owner assessments and veterinary pain scores, with no adverse effects reported during the four-week study.

A 2023 systematic review and meta-analysis of CBD for canine osteoarthritis published in Frontiers in Veterinary Science analyzed multiple intervention studies and concluded that CBD may be effective for pain management, though the authors noted limitations including small sample sizes, short study durations, and variability in CBD formulations and doses.

A 2025 study of CBD for post-surgical pain in dogs found no benefit beyond standard analgesia, suggesting that CBD's effectiveness may depend on the type and cause of pain.

A 2021 review noted that elevation in liver enzymes has been observed in both dogs and cats receiving CBD, and that long-term safety data remains limited. The review also noted insufficient information on the safety profile of CBD in cats. Check your state's laws regarding CBD for pets, and talk to your vet before starting CBD, especially if your dog takes other medications or has liver or kidney disease.

What about turmeric or curcumin for senior dogs?

Curcumin, the active compound in turmeric and the part most studies test, has been studied in combination products for osteoarthritis in dogs. A 2022 prospective clinical study published in Veterinary Medicine and Science examined a nutritional supplement containing green-lipped mussel, curcumin, and blackcurrant leaf extract in dogs and cats with osteoarthritis. The study reported improvement in mobility and comfort, though the combination formulation makes it impossible to isolate curcumin's individual contribution.

A 2025 study published in Nutrients tested a supplement containing curcumin, glucosamine, and chondroitin in police dogs with osteoarthritis and reported improvement in mobility scores. Again, the combination formulation limits conclusions about curcumin alone.

Curcumin has low bioavailability in its standard form, and some veterinary products use formulations designed to improve absorption. Talk to your vet before giving turmeric or curcumin, especially if your dog takes blood-thinning medications, has a bleeding disorder, or will undergo surgery, as curcumin may affect clotting.

When should you talk to your vet about supplements?

Talk to your vet before starting any supplement, especially if your dog takes prescription medications, has a chronic condition such as kidney or liver disease, or will undergo surgery. Some supplements can interact with medications. Omega-3 fatty acids may increase bleeding risk in dogs on anticoagulants. CBD may affect liver enzymes and how the body processes other drugs.

See your vet if your dog shows lameness, reluctance to move, difficulty standing, loss of appetite, vomiting, diarrhea, lethargy, or any other change in behavior or movement. These signs can indicate conditions that require diagnosis and medical care.

Supplements are not a replacement for veterinary care, prescription medications, or diagnosis and management of underlying disease. They may help support comfort and function as part of a broader care plan that your vet oversees.