MSM for Dog Joints: Does It Really Work?

MSM is appearing more and more often in supplements designed for canine joint comfort. Yet behind this recent popularity lies a little-known reality: MSM remains one of the least scientifically documented ingredients in veterinary medicine.

So, what exactly is MSM? Can it really support the mobility of a dog that is starting to show signs of stiffness? And what do scientific studies say?

This article provides a transparent overview backed by evidence.

What is MSM?

MSM, or methylsulfonylmethane, is a small molecule naturally present in the environment and in certain animal tissues. Chemically speaking, it is an organosulphur compound, meaning an organic molecule that contains sulphur.

Sulphur is an essential mineral for mammals. It is found in many tissues, including cartilage, tendons, ligaments, skin and hair, as well as in certain amino acids involved in cellular function.

An "organosulfur compound" — what does that mean?

Organosulphur compounds are molecules derived from living organisms that contain a sulphur atom in their structure. This sulphur participates in chemical bonds called "disulphide bridges". These bridges play an important role in protein stability, particularly in proteins that make up connective tissues such as collagen and certain components of the cartilage matrix.

In other words, MSM provides a form of sulphur that the body can readily use.

Why is this sulfur important?

Sulphur is involved in the production or stability of several key components:

1. Collagen
   This is the main protein in tendons, ligaments and cartilage. It provides strength, resilience and flexibility to joint structures. Sulphur is required during certain stages of its assembly.
2. Keratin
   A structural protein found in skin and hair. Although less directly linked to joint health, it illustrates the broad role of sulphur in tissue cohesion.
3. Connective tissues
   Ligaments, the joint capsule, synovial fluid and cartilage rely on proteins rich in sulphur bonds to maintain the joint's structure.
4. Cell repair enzymes
   Certain enzymes involved in cell renewal and protection also require sulphur.

This is why MSM is sometimes highlighted in joint supplements: it provides an essential element used by several joint structures.

Dietary supplements containing MSM

In supplements, MSM most often comes in the form of purified crystalline powder (generally at 99.9%), sometimes in capsules for humans. It is taken orally, mixed into food or diluted in water.

For dogs, there are products containing MSM alone or combined with other joint ingredients. They come as powder, tablets or soft chews. However, no optimal dose has been determined in dogs, due to a lack of clinical studies, and current recommendations are based mainly on extrapolations from human nutrition.

How might MSM act on joints?

The proposed mechanisms of MSM come mainly from laboratory studies on cells or studies in species other than dogs. They help explain its theoretical relevance, but do not prove its clinical efficacy.

A possible anti-inflammatory effect

Much of joint discomfort is linked to local inflammation. In several in vitro studies, MSM appears to reduce the activity of certain inflammatory mediators such as:

• IL-6, a molecule released during joint stress,
• TNF-α, strongly involved in chronic inflammation,
• NF-κB, a transcription factor that activates genes associated with inflammation.

In other words, this research suggests that MSM may limit the activation of these inflammatory pathways.

However, it is important to note that these observations have never been confirmed in dog joints.

Antioxidant activity described in certain models

The joint naturally produces free radicals, unstable molecules that, in excess, contribute to cartilage wear. At high concentrations, these free radicals can damage cartilage cells, alter the extracellular matrix, and sustain inflammation.

In several experimental models, MSM has been shown to stimulate the activity of antioxidant enzymes such as superoxide dismutase (SOD) and to reduce certain markers of cellular oxidation.

These results suggest that it could play a protective role against oxidative stress, even if this has not been demonstrated in dogs.

A supply of sulfur for connective tissues

Cartilage and the tissues surrounding the joint rely on molecules that require sulphur for their production, including:

• the proteoglycans, which retain water and act as shock absorbers,
• the glycosaminoglycans (GAGs), which give cartilage its flexibility,
• the collagen fibres, essential for mechanical resistance.

By providing a readily assimilable source of sulphur, MSM could theoretically help maintain these cartilaginous structures.

However, no study has shown that this intake translates into improved mobility or joint comfort in dogs.

What studies show (and their limitations)

Since there is no study on MSM in dogs, we must look at what has been done in humans and in animal models. Studies are few in number and their results show modest effects.

Studies in humans

The first data come from a randomised trial conducted by Kim et al. (2006) in 50 adults with knee osteoarthritis. Participants received 3.375 g/day of MSM or a placebo for twelve weeks. Pain scores (WOMAC) showed a statistically significant improvement in pain and function, but the effect was small, limiting its clinical relevance. In short, the improvement was statistically significant but too small to represent a major clinical benefit.

A more robust study conducted by Debbi et al. (2011) in 100 patients with osteoarthritis reached similar conclusions. After twelve weeks of supplementation at 6 g/day, pain and function improved modestly, but blood inflammation markers such as cytokines remained unchanged. The study notes that the observed benefits were 'of low magnitude' and had uncertain clinical relevance.

The observed improvements are modest and their clinical relevance remains uncertain.

Debbi et al.

More recently, Toguchi et al. (2023) evaluated 2 g/day of MSM in 88 adults with mild knee pain. The pain score (JKOM) improved significantly, but again inflammatory biomarkers (IL-1β and IL-6) showed no notable change. The observed effect remained largely subjective and moderate.

Trials generally report good tolerability over 8 to 12 weeks, with no abnormalities in blood or urine tests. Reported adverse effects include digestive issues such as bloating and mild diarrhoea, as well as occasional headaches.

Studies in dogs

To date, there is no clinical study evaluating MSM in dogs in the context of joint disorders.

No randomised trial, no dose-ranging study, and no pain or mobility measurement has been published in veterinary medicine. The proposed mechanisms and results observed in humans or animal models therefore cannot be reliably extrapolated to dogs.

In the current state of knowledge, the actual efficacy of MSM on mobility or joint comfort in dogs remains unknown.

Should you give MSM to your dog?

In the absence of studies conducted in dogs, it is difficult to recommend MSM as a reliable solution for joint comfort. Research in humans shows a real but modest effect, and animal models provide only theoretical leads, sometimes observed at very high doses that would not be transferable to a companion animal.

This does not mean that MSM is dangerous: available data suggest good short-term tolerability, mainly with some digestive issues reported in humans. But due to a lack of veterinary trials, its actual benefit for mobility, pain or quality of life in dogs remains unknown.

In practice, MSM can be considered a secondary supplement, but it should not replace approaches whose efficacy has been demonstrated in dogs: weight management, appropriate physical activity, a balanced diet and better-documented supplements such as omega-3 EPA and DHA or green-lipped mussel oil.

In summary, MSM can be integrated into an overall strategy, but its efficacy on joint disorders in dogs has not been demonstrated. Any use should be discussed with a veterinarian, especially if the dog has established pain, persistent lameness or ongoing medical treatment.

Conclusion

MSM is often presented as a complementary treatment, but the evidence remains limited. Human studies show a real but modest effect, and no clinical work has been conducted in dogs. Based on current knowledge, MSM can be considered a secondary supplement, but it should not replace solutions whose efficacy has been demonstrated in veterinary medicine, such as omega-3 or green-lipped mussel oil. Any decision regarding its use should be individualised and discussed with a veterinarian.

Scientific references

• Butawan M, Benjamin RL, Bloomer RJ. Methylsulfonylmethane: Applications and Safety of a Novel Dietary Supplement. Nutrients. 2017 Mar 16;9(3):290. doi: 10.3390/nu9030290.
• Colletti A, Cicero AFG. Nutraceutical Approach to Chronic Osteoarthritis: From Molecular Research to Clinical Evidence. Int J Mol Sci. 2021 Nov 29;22(23):12920. doi: 10.3390/ijms222312920.
• Toguchi A, Noguchi N, Kanno T, Yamada A. Methylsulfonylmethane Improves Knee Quality of Life in Participants with Mild Knee Pain: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients. 2023 Jun 30;15(13):2995. doi: 10.3390/nu15132995.
• Debbi EM, Agar G, Fichman G, Ziv YB, Kardosh R, Halperin N, Elbaz A, Beer Y, Debi R. Efficacy of methylsulfonylmethane supplementation on osteoarthritis of the knee: a randomized controlled study. BMC Complement Altern Med. 2011 Jun 27;11:50. doi: 10.1186/1472-6882-11-50.
• Brien S, Prescott P, Lewith G. Meta-analysis of the related nutritional supplements dimethyl sulfoxide and methylsulfonylmethane in the treatment of osteoarthritis of the knee. Evid Based Complement Alternat Med. 2011;2011:528403. doi: 10.1093/ecam/nep045. Epub 2011 Feb 17.
• Ezaki, J., Hashimoto, M., Hosokawa, Y. et al. Assessment of safety and efficacy of methylsulfonylmethane on bone and knee joints in osteoarthritis animal model. J Bone Miner Metab 31, 16–25 (2013). https://doi.org/10.1007/s00774-012-0378-9

This article was written by the R&D team at Laboratoire Sensilia, experts in animal nutrition.