Glucosamine and chondroitin are among the most common ingredients in joint products for dogs, and they nearly always come as a pair. Both are part of cartilage, and the thinking behind giving them by mouth is that they help preserve it. The best-run trials in dogs with osteoarthritis do not find that they relieve pain any more than a placebo does, and a 2022 review that pooled 72 trials concludes they should not be recommended for that purpose.
Sources and the two forms of glucosamine
Glucosamine is an amino sugar. The body uses it to make glycosaminoglycans and proteoglycans, the components cartilage is built from. Chondroitin (chondroitin sulphate on the label) is one of those glycosaminoglycans: a long chain of sugars found in large amounts in cartilage.
Commercial glucosamine has traditionally been made by hydrolysing crustacean shells, mainly from prawns and crabs. A more recent alternative is to produce it with microorganisms. Chondroitin, by contrast, comes from animal cartilage.
Labels list two forms of glucosamine. Hydrochloride is the one in most veterinary products, because it is cheaper to make and supplies more glucosamine per gram. Crystalline sulphate is sold in Europe as a prescription medicine for people, and it is the form that has done best in human knee trials, probably because it is better absorbed. The sulphate is usually stabilised with sodium or potassium chloride, which, as a 2017 review of its use in dogs points out, is worth bearing in mind for older dogs with heart failure, high blood pressure or kidneys that are starting to fail. The concern is theoretical; trials in people have not shown it raising blood pressure.
Does it work for dogs with arthritis?
The 2022 review: nine trials, no effect over the comparison groups
The most complete analysis to date is the systematic review and meta-analysis by Barbeau-Grégoire and colleagues, published in 2022. It gathered 72 trials in dogs and cats with osteoarthritis, drawn from 57 papers, and grouped them by type of product. Nine trials tested glucosamine, chondroitin or both. In none of them did the product relieve pain more than the comparison group, and in eight of the nine (88.9%) there was not even an improvement from the starting point. The authors conclude that these products should not be recommended for osteoarthritis pain in dogs and cats. In the same analysis omega-3 showed the clearest effect, as the article on omega-3 explains.
The Merck Veterinary Manual reflects that conclusion in its osteoarthritis chapter, revised in 2024: the available evidence does not support using glucosamine and chondroitin for osteoarthritis pain in dogs and cats.
The trials one by one
Only one trial found a benefit, and it had no placebo group. It was a 2007 trial with 35 dogs that had hip or elbow osteoarthritis, and by day 70 the dogs given glucosamine and chondroitin had improved in pain, weight-bearing and overall severity, although more slowly than those given carprofen, an anti-inflammatory. Improvement was judged on the vets' impressions rather than a validated scale, and the 2022 review adds that the difference showed up only at the day 70 check, not at the earlier ones.
A 2003 study with 71 dogs compared a glucosamine and chondroitin combination over 60 days with carprofen, meloxicam and a placebo (the placebo ran for only 30 days). A force platform measured how much weight each dog put on the affected leg. Carprofen and meloxicam improved that weight-bearing; the combination did not. Owners noticed a change only with meloxicam.
A 2017 trial put activity monitors on 60 dogs with osteoarthritis for 90 days. Half took glucosamine and chondroitin with one added ingredient, and the other half took a placebo. The monitors picked up no difference between the groups. Yet owners scored less pain in both groups, and by the same amount. The authors put this down to the caregiver placebo effect: if you expect a dog to improve, you tend to see it as better.
The most recent, by Kampa and colleagues (2023) and funded by the maker of the two marine extracts it tested, followed 75 dogs with hip osteoarthritis for 6 weeks, split into five groups, and measured the peak force with which each dog put weight on the leg while walking. Carprofen and two marine lipid extracts, both containing green-lipped mussel, improved weight-bearing compared with placebo. The glucosamine and chondroitin group (16 dogs, given a chew that also contained MSM, or methylsulfonylmethane) showed no significant improvement.
Why it may do so little
Absorption is one possible explanation, since the 2022 review notes that in dogs, only about 12% of an oral dose of glucosamine and 5% of an oral dose of chondroitin reached the bloodstream after a single dose. Another is how much products vary. The 2017 review reports that in products made for people, the real glucosamine content differs from brand to brand, and VCA Animal Hospitals warns that the active ingredients may not be the same when you change brands.
Doses used in studies
There is no established glucosamine dose for dogs. The amounts below are the ones used in the trials above, taken from the data summarised in the 2017 review and from the 2023 paper:
| Study | What the dogs took | Amount | Duration |
|---|---|---|---|
| 2003, 71 dogs | Capsules with 500 mg glucosamine hydrochloride, 400 mg chondroitin and 75 mg manganese ascorbate | Dogs under 45 kg: 3 capsules a day for 30 days, then 2 a day. Larger dogs: 4 a day, then 3 | 60 days |
| 2007, 35 dogs | Product with 475 mg glucosamine hydrochloride and 350 mg chondroitin per gram | 1 g, 1.5 g or 2 g twice a day for dogs of 5 to 19.9 kg, 20 to 40 kg or over 40 kg. From day 42, a third less | 70 days |
| 2023, 16 treated dogs | Chew with glucosamine, chondroitin, MSM and avocado and soya extract | 30 mg glucosamine hydrochloride per kg of body weight a day | 6 weeks |
For chondroitin, the 2017 review gives a suggested 15 to 30 mg per kg, taken from a standard veterinary formulary. The same review mentions the idea that it takes 2 to 6 weeks before anything is noticeable, and warns that no clinical data back that up.
Side effects and when to see your vet
The trials reported few problems: no serious adverse effects were recorded in the 2017 trial, and in the 2007 trial two dogs stopped treatment because of reactions that are not described. According to VCA's page on glucosamine and chondroitin, it can cause mild stomach upset, meaning wind and soft stools. Irregular breathing, a rash, fever or a swollen face are signs of an allergy; if you see them, stop giving it and call the vet.
Check with the vet before starting in any of these cases:
- If your dog has a diagnosed crustacean allergy, also ask the manufacturer where the glucosamine comes from.
- If it has diabetes, VCA advises caution alongside insulin and other diabetes medicines.
- If it takes anticoagulants (heparin, warfarin), some anti-inflammatories (firocoxib, diclofenac, carprofen), doxorubicin or sertraline, VCA advises monitoring the combination, although it does not rule it out.
- If it has asthma, is on a low-potassium diet, or is pregnant or lactating, VCA recommends using it with caution.
- If it has heart, blood pressure or kidney problems, check whether the product uses glucosamine sulphate stabilised with salt, for the reason given above.
If your dog eats a lot of chews at once, or a whole jar, phone the vet with the packaging to hand. According to Pet Poison Helpline, a glucosamine overdose usually causes nothing worse than diarrhoea, but in rare cases it can lead to liver failure.
A dog that limps, struggles to get up or no longer wants to climb stairs needs a diagnosis before anything else. Osteoarthritis hurts. The 2017 review names anti-inflammatories as the standard drug treatment, and weight loss, adapted exercise and physiotherapy as the options that do not involve drugs. On what has been published so far, glucosamine and chondroitin cannot stand in for any of them.
Sources
- A 2022 Systematic Review and Meta-Analysis of Enriched Therapeutic Diets and Nutraceuticals in Canine and Feline Osteoarthritis. International Journal of Molecular Sciences, 2022.
- Osteoarthritis in Dogs and Cats. Merck Veterinary Manual, 2024.
- Randomised double-blind, positive-controlled trial to assess the efficacy of glucosamine/chondroitin sulfate for the treatment of dogs with osteoarthritis. The Veterinary Journal, 2007.
- Clinical evaluation of a nutraceutical, carprofen and meloxicam for the treatment of dogs with osteoarthritis. Veterinary Record, 2003.
- Efficacy of an oral nutraceutical for the treatment of canine osteoarthritis. A double-blind, randomized, placebo-controlled prospective clinical trial. Veterinary and Comparative Orthopaedics and Traumatology, 2017.
- 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.
- Glucosamine and chondroitin use in canines for osteoarthritis: A review. Open Veterinary Journal, 2017.
- Glucosamine Chondroitin Combination. VCA Animal Hospitals, 2025.
- Microbial glucosamine production: current strategies, process bottlenecks, and future perspectives. Letters in Applied Microbiology, 2026.
- 10 Most Common Items Toxic To Pets. Pet Poison Helpline, 2013.