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

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

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

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.

I found this article by Dr. Ramey to be very informative.  I love his articles.

Among the most widely advertised supplements for horses are products that contain glucosamine salts, chondroitin sulfate, or both.  From an economic standpoint, these products are wildly successful; the market for such products in the human fields is around one BILLION dollars.  However – and perhaps amazingly – there is very little evidence to show that they actually work.  I personally believe that the products are a waste of money (and they are expensive), being sold mostly on promise, with little in the way of positive results obtained from good trials.  Here’s some information about the products in horses that might help you make up your own mind.

GLUCOSAMINE

Glucosamine is an sugar compound that is made in the horses body.  It’s incorporated into many of the horse’s body’s molecules, including joint cartilage, however, it is NOT necessary for the synthesis of cartilage (the body uses the sugar, glucose, to build cartilage).  Small amounts of glucosamine can detected in the bloodstream of horses, but no deficiency has ever been reported, in any species.  The glucosamine that you may buy for your horse comes mostly from the shells of crustaceans.

A number of test-tube studies have shown that glucosamine has biological activity, and various beneficial effects on cartilage cells.   While this should be great news, it should be noted that these studies have generally been conducted with levels of glucosamine that can’t be reached when the substance is fed to horses.   In fact, only 2 – 5% of the glucosamine that is fed to the horse actually is available for the horse, and, at the levels normally fed, it’s hard to see how it could have any effect at all on the horse (the test tube studies are usually conducted at concentrations from 200 – 2000 times higher than what can be reached by feeding the stuff).   Even though one test tube study, done on cultured horse cartilage cells, did show beneficial effects, those effects still haven’t been shown to occur in living horses.  Thus, in general, there’s good reason to doubt whether ANY of the information obtained from test tube studies is relevant to preventing or treating arthritis in horses.

It has recently been shown that glucosamine levels are higher when horse joints are inflamed.  This raises the possibility that glucosamine might be useful in joints to treat arthritis.  There’s also some suggestion – obtained from work in mice – that glucosamine could have some indirect effects by reducing products of inflammation produced in the liver.  But the fact is that no matter how interesting these experimental results, they have yet to be shown to be important clinically in actual horses.

Perhaps amazingly, given the amount of product sold, there have been no clinical studies on the effectiveness of orally administered glucosamine by itself for the treatment or prevention of arthritis in horses.  Even so, the information obtained from other species suggest that while results are often positive, the effects are very mild, and probably not really very important.  In humans, even though there have been many clinical trials on glucosamine, there’s still much controversy as whether it’s effective.  Most well-conducted, large, independently-funded clinical trials in humans show no effect at all (on the other hand, when industry pays for the trials, they are five times more likely to be effective)!

There are two glucosamine salts – glucosamine hydrochloride, and sulphate.  Some people have suggested that the horse’s intestinal tract absorbs the two compounds differently, and thus assert that glucosamine sulphate may be more effective. However, in the horse’s stomach,  both compounds ar split into glucosamine, so it’s hard to see why that would be true.  Even though one study, in horses, shows that the glucosamine sulphate preparation reaches higher levels in the joints (compared to the hydrochloride salt), the levels aren’t so different as to be clinically relevant, and might just mean that the sulphate preparation tasted better (and the horses ate more of it).

Horse owners should be be aware that the products being sold to them may not contain much glucosamine in them.  Two studies (including one by Dr. Ramey), show that there is a huge variation in the amount of glucosamine available in the products.  Otherwise stated:  there may not be much glucosamine in your horse’s glucosamine.

The currently recommended doses of glucosamine are about 20 mg/kg.  For most average horses, that means a dose of around 2000 mg a day.

CHONDROITIN SULFATE

Chondroitin sulfate (CS) is a sugar molecule found in cartilage, bone, tendons, and ligaments. The CS fed to horses comes from animal sources (cow, chicken, pork, and even marine cartilage), so the actual make-up of the product fed to horses depends on where it comes from.  Because of this, there is also variation in absorption, which is another reason for concern.

It’s an open question whether any CS is absorbed at all. In humans, ingesting CS, doesn’t change blood levels; if blood levels don’t increase, it can’t have any direct effects on joints!  Some people have suggested indirect effects, due to elevated levels in the intestine, or in the liver, but this is just speculation, and hasn’t been demonstrated.   The fact that CS isn’t well absorbed also casts doubt on the relevance of all of the test tube studies; if it can’t get into the body, who cares what happens in the test tube?

So far, there has only been one clinical experimental study in horses that looked at the effects of CS given in the muscle; no beneficial effects were noted. In addition, different CS compounds that come from different manufacturers act differently in test tube experiments.  This, of course, means that you unless you know specifically what’s in the product you’re feeding to your horse, you can’t anticipate any positive result.

COMBINATION OF CHONDROITIN SULFATE AND GLUCOSAMINE

While there’s a large amount of conflicting evidence, from many species, three clinical trials have looked at the combination of glucosamine hydrochloride and CS specifically in horses.  All of them have reported beneficial effects on symptoms of joint disease; all of them were funded by industry. The most recent study, which did appear to be well-conducted, suggested that the combination offered some symptomatic relief in lameness.

There don’t appear to be any side effects associated with the use of the combination, and 5 times the recommended dose can be safely administered to horses.  That’s not necessarily a good thing, however;  in people, when glucosamine is combined with CS, the levels of glucosamine measured in the blood are lower than those reached when glucosamine is given alone.  This suggests that CS actually inhibits glucosamine absorption.

THE BOTTOM LINE

If you’re looking for a readily available product to give to you horse in hopes of treating arthritis, there are plenty of them for you to buy.  However, you may not be buying what you think you’re buying, and there’s little reason to believe that the products will help your horse.