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 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).
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.
So the long and the short of it is that there is evidence that the components of supplements - of sufficient quality and quantity - can have an effect on horse joint health. However, just because a supplement lists these ingredients does not mean they are in the correct quantities or of sufficient quality to be beneficial.
It is NOT a race to the top for the most of anything. Cavalor's research focuses on the optimum quantities and qualities of ingredients rather than simply putting the most of anything in the product. Indeed it is known that poor quality ingredients (Martel-Pelletier, 2015) may actually have the opposite effect.