Glucosamine/Chondroitin for Joint Pain
Glucosamine is found naturally in the body's joint cartilage -- helping keep it healthy and lubricated. The shells of shrimp, lobster, and crab provide the basis for these supplements. Glucosamine is believed to help slow deterioration of cartilage, relieve arthritis joint pain, and improve joint mobility.
Chondroitin is also found naturally in cartilage and bone. Chrondroitin sulfate supplements are derived from cow trachea or pork byproducts. Chondroitin is said to reduce joint pain and inflammation, improve joint function, and slow progression of osteoarthritis. Most studies have been done on knee arthritis.
Chondroitin is believed to enhance the shock-absorbing properties of collagen and block enzymes that break down cartilage. Like glucosamine, this supplement is thought to help cartilage retain water, keep joints lubricated, and possibly reverse cartilage loss.
The research on these supplements is mixed. In a 2005 review of glucosamine, 20 studies involving 2,570 patients were analyzed -- showing glucosamine to be safe but not better than a placebo in reducing pain and stiffness and improving function. However, a World Health Organization review of evidence on glucosamine found that it relieves arthritis-related knee pain and improves joint function.
In 2006, the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), funded by the National Institutes of Health, found the two supplements were more effective when combined. However, only people with moderate or severe pain from knee arthritis reported significant benefit. They got better pain relief than from an anti-inflammatory painkiller.
In September 2008, a follow-up GAIT study compared people who took the supplements or medication for an additional 18 months. All those patients had moderate to severe osteoarthritis knee pain. After two years, there was no significant difference between the treatment and placebo groups.
There was a slight trend toward improvement among those with milder osteoarthritis of the knee who were taking glucosamine alone -- but not enough to draw definite conclusions, according to the lead researcher.
Robert Bonakdar, MD, director of pain management at Scripps Center for Integrative Medicine, takes issue with the NIH study, calling it "very flawed." The biggest problem, he tells WebMD, is that the study tested a relatively ineffective form of glucosamine.