Due to the great variety of joint supplements on the market, this discussion will be limited to the various ingredients commonly used in joint supplement, not brand names. The purpose of joint supplements are to provide building blocks for cartilage and synovial fluid, and to reduce inflammation and cartilage degradation. Most oral joint supplements contain varying amounts of glucosamine, chondroitin sulfate (CS), Methylsulfonylmethane (MSM), and minerals, or a combination of these.
Glucosamine is a building block for cartilage and joint fluid and has been shown to stimulate the building of cartilage and inhibit inflammation. Glucosamine is well absorbed in the horse gut and is accepted as a valid therapeutic approach for the management of degenerative joint disease in horses and as an alternative to injectable therapies where cost is an issue.
CS inhibits inflammation and tissue destruction. However, absorption of CS has been reported for man, dogs, and rats at less than 15%. Absorption in horses has not been studied.
MSM is a source of bioavailable sulfur and is believed to have anti-inflammatory effects, but these effects have not yet been proven.
Minerals are important constituents of enzymes that control cartilage synthesis. They are included in many joint nutriceuticals (non-regulated products) to insure against dietary deficiencies. Sulfur plays a part in the biosynthesis of glucosamine and collagen, manganese is an essential part of the enzyme involved in the synthesis of CS, zinc is a component of the enzyme that controls the production of collagen in cartilage, and copper is also involved in collagen production.
Because of the wide variability and amount of active ingredient of minerals, their purity and availability after oral administration is sometimes unknown. When using joint supplements, it is important to consult with your veterinarian and to rely on trusted, proven brands.