The exact way these substances work in the joint is not completely known. Animal studies have shown that when chondroitin is taken orally, it accumulates in the joint, and may neutralize destructive enzymes that would otherwise cause cartilage damage. Laboratory tests dating back to the 1950s showed that glucosamine sulfate stimulated cartilage production in special cells found in joints. Some researchers believe that glucosamine is effective only in the sulfate form, due to the importance of sulfur in the production of normal connective tissue.
Although the benefits of glucosamine and chondroitin sulfate for animal joint problems had been known for many years, Dr. Jason Theodasakis' book The Arthritis Cure forced the medical community to investigate their use in people. Since that time, many studies have shown they work in humans too!
In a recent study of these two substances, researchers from the Arthritis Center, Boston University School of Medicine, reviewed fifteen human studies on the use of glucosamine and chondroitin for joints. The results of this meta-analysis showed a significant improvement in joint pain for patients using either substance. Each underlying individual study also showed them to be extremely safe, with almost no side-effects. The range of doses were 500 to 1,500 mg of glucosamine and 800 to 1,200 mg of chondroitin daily in the sulfate form. A second meta-analysis of the effects of chondroitin on arthritis by Leeb, was similarly positive. In both studies, reliable benefits took 4 to 8 weeks to occur. Many of the Glucosamine and Chondroitin Combos we sell have this same effective ratio.
The National Institutes of Health (NIH) is currently sponsoring a large study on these two substances. Their data will likely confirm what almost 30 previous studies have shown, that glucosamine and chondroitin sulfate help reduce arthritis pain and may even promote cartilage regrowth.