By Suzie Middlebrook BSc | Cavalor Nutrition Specialist

Joint supplements are one of the most commonly used supplements in equine industry, but they are also one of the most controversial. Advice and research from both the veterinary and orthopedic communities is inconsistent at best. Are joint supplements truly beneficial for people’s horses or are they just throwing money away?

The trickiest part of all supplements is that there is little regulation to determine their efficacy. All statements that claim a supplement can treat, cure, or prevent any kind of disease must be verified by the FDA. Once these claims are verified through a long and expensive process, the supplement is subsequently considered a drug and strictly regulated by the FDA. What supplements can claim, however, is that the ingredients of those supplements have been shown to have beneficial properties. Given that many of joint supplements contain a number of the same ingredients – glucosamine, chondroitin, hyaluronic acid, MSM – this further complicates the task of choosing one! By examining the latest research and recommendations from the scientific community, we can develop a more thorough understanding of why the mentioned ingredients and others are used in joint supplements, what they are believed to do for joint health, and their efficacy. This knowledge will then better allow us to better determine which joint products are the best for our horses.


Glucosamine is one of the most common active ingredients in equine joint supplements. This compound is considered an amino saccharide, meaning it has elements of both proteins and sugars. Glucosamine is believed to have joint-protection properties since it is a known precursor to both hyaluronic acid and glycosaminoglycans. Hyaluronic acid is a component of synovial fluid – the liquid that lubricates the joints – while glycosaminoglycans are one of the major building blocks found in cartilage – the flexible “cap” found covering bones at various joints, such as the stifle or the pastern. With this in mind, it is reasonable to think that, by feeding glucosamine, one can assist the body’s repair and rebuilding efforts to help stave off the effects of arthritis.

Unfortunately, that is not the case.

In feeding trials involving horses being fed glucosamine hydrochloride, the amount of glucosamine found in the blood after feeding a reasonable amount of glucosamine was less than 2% of that feed (Percope de Andrade, 2014). If we do the math, that means if a horse is given 10,000 mg of glucosamine hydrochloride, only 200 mg of the original amount fed survives being chewed, acid-soaked, digested, and absorbed into the blood stream. Only that 200mg of remaining glucosamine found in the bloodstream is able to have a positive effect on the joint health of the horse. Another form of glucosamine, known as glucosamine sulfate, does seem to be significantly more available to the horse and, therefore, more able to actually reach the bloodstream intact. While more studies need to be done to fully understand the impacts of glucosamine sulfate in the horse, supplements containing glucosamine sulfate do seem to have a measurable, positive impact on mobility and pain relief.


Chondroitin is a protein that is responsible for the compressive resistance found in the joint and is important for maintaining joint integrity, particularly for horses that are in consistent, rigorous work. Chondroitin is most commonly found in the form of chondroitin sulfate. In humans, chondroitin sulfate is shown to help decrease cartilage loss, which can help preserve long-term joint function in active adults (Gallagher, 2015). The large issue with chondroitin is that there is a huge amount of variation in the source, amount, and purity found within supplements (Martel-Pelletier, 2015). While majority of chondroitin-containing supplements have anti-inflammatory effects, sometimes these effects are marginal. Even worse, sometimes these supplements are in fact pro-inflammatory, possibly due to impurities in the chondroitin source used. This information indicates the horse owner should try to use a supplement manufacturer they trust to ensure that only pure chondroitin sulfate from high quality sources are used.

Hyaluronic Acid

Hyaluronic acid is a protein found throughout the body, including the skin, brain and connective tissues. It is also one of the primary components found within synovial fluid, which is the fluid that is found within the joints and responsible for lubricating these joints for pain-free locomotion. This compound is widely found to be effective in helping young horses recover from OCD in both surgical and non-surgical cases when given orally (Bergin, 2006; Carmona, 2009). Oral hyaluronic acid is also well known to help reduce synovial effusion. Synovial effusion is an inflammatory response that causes joint swelling and, subsequently, a decrease in mobility and sometimes pain. In older horses, oral hyaluronic acid has been shown to have anti-inflammatory benefits and help improve locomotion (Percope de Andrade, 2013). Generally, the beneficial effects seen are when 100 mg to 250 mg of hyaluronic acid is given orally on a daily basis.


Methylsulfonylmethane, or more commonly referred to as MSM, is an easily absorbable form of sulfur. Sulfur is a primary building block of numerous structures, including joints, tendons, and ligaments. While MSM is not as well-researched in horses as some of the other nutraceuticals mentioned, there have been promising studies that look into the effect MSM has on joint health in other species. One study examined mice fed MSM at various levels over several months (Ezaki, 2013). After 13 weeks, the mice fed the MSM were observed to have a significant reduction of joint degeneration. In another study, MSM was observed to have an analgesic effect in people with known arthritic changes (Nakazone, 2011). This information strongly supports the use of MSM in horses with some degree of joint degeneration.

Omega 3 Fatty Acids

Omega 3 fatty acids are often perceived as the wonder nutrient when it comes to overall health. The anti-inflammatory effects of omega 3 fatty acids are well documented in variety of fields (NRC, 2007). In the equine nutrition world, there are two forms of omega 3 fatty acids that are commonly used: ALA and DHA. ALA or alpha-linolenic acid is the type of fatty acids commonly found in seeds, such as flaxseed and chia seed. While effective, the inflammatory effects of ALA are far surpassed by DHA. DHA, or docosahexaenoic acid, is the fatty acid found in fish oils which makes it fairly unappetizing to the average horse. While the improved anti-inflammatory effects of DHA are noteworthy, the source of this fatty acid makes it generally unappetizing to the horse unless it is masked by other substances such as herbs. Beyond palatability issues, DHA is also more difficult to obtain and, in consequence, more expensive. That said, the omega 3 fatty acid DHA was seen to be the most effective nutraceutical examined in one study that looked at the effect of various compounds and their effects on pain and movement in the horse (Vandeweed, 2012).

More generally, omega 3 fatty acids of any form are still very effective in reducing chronic pain and inflammation in horses. Two separate studies both showed that omega 3 fatty acids may be more effective in more advanced cases of arthritis, including traumatic injuries involving the joint (Cai, 2014; We, 2014). Of all five of the nutraceuticals mentioned, omega 3 fatty acids have the most consistent results in a variety of circumstances and species to help improve movement, reduce pain, and support healing for individuals that are suffering from arthritis.

After examining some of the most recent research available on some of the most commonly used ingredients found in joint supplements, horse owners can have a more thorough understanding of what helps their horse, what hinders them, and what to look for when choosing a joint supplement.

An effective, comprehensive joint supplement would definitely have omega 3 fatty acids, preferably in the DHA form, and at least 100mg of hyaluronic acid per dose. While more information is needed, incorporating MSM should help contribute the further reducing inflammation. Chondroitin can be a good addition if the product is made by a well-respected company, but be careful since not all chondroitin is created equal. As for glucosamine, if it is in the form of glucosamine hydrochloride, it is of minimal benefit to the horse beyond being an additional protein source. If you need glucosamine in your horse’s diet, try to find glucosamine sulfate since this has a higher chance of actually getting to your horse’s joints.


About Suzie Middlebrook, BSc | Cavalor Nutrition Specialist

Suzie Middlebrook is a budding equine nutritionist and lifelong equestrian. She graduated from California Polytechnic State University in San Luis Obispo, CA with her bachelor’s degree in animal science where she focused on equine and wildlife nutrition. While there, Suzie was instrumental in a number of feeding trials and experiments that looked at the fiber and mineral digestion in a number of different herbivorous species, including the red panda, the leopard tortoise, and the horse. Her personal project looked into developing an accurate and practical digestion model for the endangered red panda which she presented as an undergraduate at the Association of Zoos and Aquariums/Nutrition Advisory Group conference on Zoo and Wildlife Nutrition in 2011. Suzie loves talking and teaching about the peculiar nuances of equine nutrition and is able to do so as the Nutritional Specialist for Cavalor North America. When not “nerding out” on nutrition, Suzie enjoys competing her two horses in dressage and eventing, trail running, and playing with her boxer dog.