Glucosamine and chondroitin are ubiquitous: found in food supplements, "joint" kibbles, and many products for aging or arthritic dogs.

However, their reputation is largely driven by marketing. When clinical trials, systematic reviews, and meta-analyses are considered, the picture is much more nuanced.

This does not mean that these molecules are useless for all dogs. However, the available evidence does not allow them to be presented as treatments with clearly demonstrated efficacy against pain.

Today, the best scientific syntheses conclude that their analgesic effect is weak, or even absent, and that it is not reproducible enough to be recommended as a reference treatment for osteoarthritis.

What are we talking about?

Glucosamine is a sugar naturally involved in the formation of cartilage and other connective tissues. It is sold in various forms, mainly as sulfate or hydrochloride.

Chondroitin sulfate is a natural component of the cartilage matrix. It is almost always associated with glucosamine in supplements for dogs suffering from osteoarthritis.

The idea seems logical: provide elements that make up cartilage and limit its degradation.

But a credible biological hypothesis is not enough to demonstrate a clinical benefit. This is precisely what studies show.

An appealing mechanism... but still theoretical

In the laboratory, glucosamine could participate in the synthesis of glycosaminoglycans and proteoglycans, two important components of cartilage.

Chondroitin, for its part, could be involved in the mechanical properties of cartilage and limit the action of certain enzymes involved in its degradation.

These mechanisms are plausible.

However, an essential step remains to be demonstrated: after ingestion, are the molecules sufficiently absorbed? Do they actually reach the joint in sufficient quantity? And above all, does this presence improve the dog's condition?

It is on these questions that the results become much less convincing.

What the studies actually show

The most robust reference today is the systematic review with meta-analysis published by Barbeau-Grégoire et al. in 2022.

The authors analyzed 57 publications comprising 72 clinical trials on various nutraceuticals used in dogs and cats suffering from osteoarthritis.

Their conclusion is clear: products containing glucosamine and chondroitin do not show a significant effect on pain and should no longer be recommended as analgesic treatment for osteoarthritis.

This conclusion is important because a meta-analysis gathers all available data and offers a much higher level of evidence than an isolated study.

The most frequently cited trial in favor of these molecules is that of McCarthy et al. (2007). The authors reported an improvement in certain clinical parameters after about ten weeks of supplementation.

However, the improvement remained slower than with carprofen, did not concern all criteria studied, and was not consistently confirmed by subsequent published work.

A more recent study, published in 2023 on dogs with hip osteoarthritis, reached the same conclusion: unlike other nutraceuticals, glucosamine and chondroitin did not improve an objective measure of locomotion.

In summary, some studies report encouraging results, but when considering the entirety of scientific literature, evidence of clinical benefit remains weak and insufficient to recommend these molecules as a reference treatment for osteoarthritic pain.

Dosages: many recommendations, few certainties

Contrary to a widespread belief, there is currently no dose of glucosamine or chondroitin whose clinical efficacy has been clearly demonstrated in dogs.

Studies use very different formulations, concentrations, and protocols, which makes comparisons difficult.

In other words, when a manufacturer claims that a specific dosage is "scientifically validated," this assertion goes beyond what the available data actually allow to conclude.

Highly variable absorption

Not all glucosamines are equal.

In dogs, studies show that only a small portion of orally administered molecules is actually absorbed. They also show that this absorption varies depending on the chemical form used—sulfate or hydrochloride—but also on the product's formulation, liquid or solid.

In other words, two supplements containing the same amount of glucosamine can expose the body to very different concentrations.

This variability further complicates the interpretation of studies and partly explains why their results are sometimes contradictory.

Why is so much glucosamine and chondroitin still found?

Given the scientific data, a question often arises: why are these molecules still present in so many food supplements?

The answer is quite simple.

They have been used for several decades, are generally well-tolerated, inexpensive, and have strong recognition among owners. Many formulations therefore continue to incorporate them, even as scientific knowledge has evolved.

Their presence in a product does not mean it is ineffective. However, it also does not constitute proof of its effectiveness.

Tolerance and precautions

Glucosamine and chondroitin are generally well-tolerated in dogs.

Adverse effects observed are most often digestive and remain moderate: softer stools, diarrhea, vomiting, or transient digestive discomfort.

Drug interactions are poorly documented. As a precaution, it is recommended to inform your veterinarian of any food supplement administered, especially in elderly dogs, those on multiple medications, or those with a chronic illness.

As glucosamine is generally produced from crustacean shells, veterinary advice is recommended for dogs with a known allergy to these proteins. Plant-based formulations are also available.

What to remember

Glucosamine and chondroitin are among the most popular joint supplements for dogs.

Their mechanism of action is biologically plausible, and their safety profile is generally satisfactory. However, the best available scientific data do not show a clearly demonstrated benefit on osteoarthritis-related pain.

They can be used as supplements in certain approaches but should not be presented as treatments with firmly established efficacy.

Osteoarthritis management relies primarily on a global strategy combining weight control, adapted physical activity, rehabilitation when possible, and treatments prescribed by the veterinarian when their use is indicated.

 

Why Canithermo Mobility does not contain them This is also why we did not include glucosamine or chondroitin in the formulation of Canithermo Mobility. We chose to select ingredients with a stronger level of scientific evidence regarding joint comfort and mobility in dogs today. Our objective was not to include the best-known active ingredients, but those for which the scientific data seemed most convincing to us.