MSM for Dogs: What You Need to Know

MSM is an organosulfur compound that provides some of the basic materials the body uses in the production of collagen and glucosamine. Since these are both components of healthy joints, MSM has been studied in humans for its ability to promote joint health. It has also been studied for potential anti-inflammatory and antioxidant effects.  

However, MSM should not be used as a stand-alone treatment for arthritis or joint pain, or in dogs with a sudden onset of new symptoms. If your dog starts to limp, shows signs of pain, or has swollen joints, make an appointment with your veterinarian to develop a comprehensive care plan.  

Dog-specific studies involving MSM are lacking and most of the research has been conducted in mixed-ingredient supplements, so it’s hard to isolate MSM’s benefits. In some of those studies, dogs have shown increased mobility and fewer signs of pain, but these benefits could also be caused by other ingredients in the supplement mix.  

In human research, MSM has been shown to help modulate inflammation and reduce markers of oxidative stress, which has been linked to various diseases including arthritis.  

Overall, MSM appears to be well tolerated in dogs.  

Dog-specific safety data are limited, so it’s difficult to predict how every dog will respond. In people, MSM is considered to be generally well-tolerated at recommended doses. When side effects are seen, they typically involve digestive upset, including:  

• Vomiting  
• Diarrhea  
• Flatulence 
• Reduced appetite  
• Itching or skin reactions  

It’s important to check the exact product and ingredient list before giving any new supplement to your dog. Because MSM is a supplement and the manufacturing isn’t regulated, the quality and quantity of ingredients can vary from product to product. It’s best to pick a product recommended by your vet, or to look for one that has been tested.  

If your veterinarian thinks MSM fits your dog’s plan, use a product made for dogs and follow the label and your vet’s instructions. Don’t combine multiple supplements without asking first, since combining products can make it harder to keep track of what your dog is getting and can result in doubling up on certain ingredients. 

If your dog may have taken too much MSM or seems off after receiving it, call your veterinarian, an emergency hospital, or the Pet Poison Helpline (855-764-7661) right away. Have the bottle handy so you can share information about the product with the vet or poison expert. If you think your dog is having an adverse reaction, stop the supplement and get professional advice promptly.  

Is MSM the same as DMSO? 

Not exactly. MSM as the oxidized form of dimethyl sulfoxide, or DMSO, so the two compounds are related but not the same.  

Can MSM replace my dog’s prescribed medicine?

No. Supplements should not be used as a substitute for a veterinarian’s diagnosis, prescribed medicine, or tailored care plan. 

Is MSM better than other joint-supplement ingredients? 

There is no universal best choice for every dog. The right option depends on your dog’s health history and your veterinarian’s guidance.  

Should I ask my vet before starting MSM? 

Yes. That’s the safest move, especially if your dog has a chronic condition or takes medication or other supplements.