Chondroitin sulfates are not universally embraced, but there are those who swear by them when it comes to easing the pain of sore jointsAnecdotal information about feed supplements containing chondroitin sulfates and their supposed ability to reduce joint inflammation gets passed from shedrow to shedrow and farm to farm. Some trainers, stable managers, and grooms feeding supplements with chondroitin sulfates swear they see improvement in animals that are sore or just mysteriously "off." Veterinarians recommend them when conventional treatments fail to relieve a horse's symptoms.
The problem is that no scientific research directly links feeding chondroitin sulfates, also known as glycosaminoglycans, or GAGs, with the prevention, relief, or reversal of joint inflammation or joint deterioration in horses. Some manufacturers cite chondroitin sulfate studies on rats, dogs, and humans, leaving their equine customers to make the mental leap that what goes for a man or a rat goes for a horse, too. However, nutritionists point out that the studied species have very different digestive systems from that of the horse, and extrapolating results from one species to another is not always completely valid. Much more research is needed that is specific to horses.
Are Thoroughbred owners wasting their money feeding these supplements in an effort to alleviate joint problems?

Reading labels
The horse industry has appropriated the term "nutraceutical" from the Foundation for Innovation in Medicine, which coined it in 1989 to describe food products with a reputation for reducing or relieving symptoms. Horse supplements containing chondroitin sulfates fall into this nutraceutical category.
Manufacturers producing nutraceuticals make no medical claims on their products' labels and point-of-sale materials lest they draw the wrath of the Food and Drug Administration. The government's primary avenue for regulating animal feeds is through their labeling and through the FDA's Center for Veterinary Medicine, which in cooperation with state agencies around the country closely monitors the wording manufacturers use on product labels to be sure there are no false claims.
Any health or medical claims on a food product's label moves it into the category of a drug or medicated animal feed. To market one of those requires exhaustive and expensive testing to prove the health claims, a costly process most manufacturers try hard to avoid.
Carefully worded ad copy, selected testimonials, and other manufacturer's literature, however, often lead horsemen to infer what labels dare not say directly-that feeding a particular supplement will help their horse overcome a medical problem.

How they work
The jargon surrounding this particular class of nutraceuticals includes big words like chondroitin sulfates, glycosaminoglycans, and mucopolysaccharides. Glycosaminoglycans or mucopolysaccharides (the scientific community changed terminology in the 1960s, and both sets of terms are now found in the literature about these substances) are found in cartilage and in the viscous synovial fluid surrounding and lubricating the joints. There are nine of them in all. One is hyaluronic acid, which has been used by the veterinary community in an injectable form to treat joint problems. Three others are chondroitin sulfates, often identified as A, B, and C. There are several over-the-counter feed supplements on the market containing chrondroitin sulfates (and one FDA-approved injectable product containing polysulfated glycosaminoglycans, or PSGAGS, which is available by prescription.)
The basic theory is that when the horse eats the chondroitin sulfates, the sulfates migrate through the gut wall and find their way to the horse's joints. There they supplement the chondroitin sulfates produced by the horse's own body to reduce joint friction.
Whether chondroitin sulfates can make it through the horse's digestive tract, into the bloodstream, and then to the horse's joints is the question. Skeptics argue that mucopolysaccharides (which roughly translates into "sticky strings of sugars") are such large molecules that it is impossible for them to pass through the gut wall intact. To get to the bloodstream, they must be broken down into smaller particles. And it is ludicrous, they say, to believe that once on the other side, they reassemble into long strings again before migrating to the joints.
Believers counter that the electrical charge of the molecules may be more important than their size in getting them through the gut wall, and by linking up with other molecules, such as certain amino acids, they may get a "free ride" through the gut wall into the bloodstream. There is also speculation that getting the molecules across the gut wall intact is not important, that the broken up molecules provide needed nutrients, such as sulfur, for promoting normal synovial fluid production.
Recently, FDA approved the injectable drug Adequan for use in horses after its manufacturer proved to the agency's satisfaction that
PSGAGS introduced intramuscularly do make their way into the horse's joints in satisfactory amounts with positive effects. The manufacturer's studies show that if a preparation of polysulfated glycosaminoglycans from bovine trachea is injected into muscle, bypassing the gut entirely, it promotes formation of new cartilage, helps restore synovial fluid, and reduces inflammation and pain.

Talk to the animals
The good news is that feeding chondroitin sulfates to animals that do not need them does not appear to be harmful. The bad news is that they do not help every animal that receives them. Other than educated guesses, there are no studies that offer any data about the percentage of horses that might be helped or which particular lamenesses or sorenesses are most likely to respond.
Another problem is purity and whether customers are really getting what they are paying for. Most of the chondroitin sulfates used in equine feed supplements come from powdered animal cartilage, usually bovine tracheas. The level of chondroitin sulfate can vary enormously from one batch of animal cartilage to the next and some manufacturers have less stringent quality controls than others.
Freeze-dried Perna canaliculus mussels from Australia are a unique source of chondroitin sulfates. Although Perna mussels have a much smaller percentage of chondroitin sulfate than animal cartilage, they also contain many other nutrients. It is this total "nutritional complex," say its advocates, that makes it effective in promoting healthier joints.
For all the lack of scientific data specific to equines, there is a wealth of anecdotal evidence indicating that horses fed chondroitin sulfates for joint problems often show improvement. While a certain number of these "cures" may simply be the owner's wishful thinking or the application of a healthy dose of tincture of time, the number of them suggests that chondroitin sulfates can help some horses.
Like other feed supplements on the market, chondroitin sulfates should not be looked upon as magic bullets that will cure whatever ails a horse. Before simply feeding what the guy down the row feeds because it helped his horse, first consider how alike the two situations really are. Have the animal thoroughly checked by a vet, and ask whether chondroitin sulfates are one possible treatment. Try to change just one thing about the horse's feeding program and training regimen at a time so it is clearer what action is causing what effect. Call or write the manufacturers of several products to find out what quality control measures they use to ensure that the level of chondroitin sulfates in their product is consistent from batch to batch. Ask if they use an independent testing lab to help maintain that quality control.
Finally, despite everything you read, do not expect powdered miracles. While chondroitin sulfates may help relieve the symptoms of joint degeneration, you may have to look a little harder and a little farther to find and eliminate the causes.