Chondroitin is a molecule that occurs naturally in the body. It is a major component of cartilage -- the tough, connective tissue that cushions the joints. Chondroitin helps to keep cartilage healthy by absorbing fluid (particularly water) into the connective tissue. It may also block enzymes that break down cartilage, and it provides the building blocks for the body to produce new cartilage.

A number of scientific studies suggest that chondroitin may be an effective treatment for osteoarthritis (OA). OA is a type of arthritis characterized by the breakdown and eventual loss of cartilage, either due to injury or to normal wear and tear, and commonly occurs as people age. Chondroitin supplements have been shown to decrease the pain of OA. Some researchers think it may actually slow progression of the disease, unlike other current medical treatments for OA. (Many people take either acetaminophen or nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, for OA pain). However, so far studies have not shown conclusively that chondroitin helps repair or grow new cartilage, or stops cartilage from being further damaged. Chondroitin is often taken with glucosamine, another supplement thought to be effective in treating OA.

Treatment

Osteoarthritis

Results from several well-designed scientific studies indicate that chondroitin supplements may be an effective treatment for OA, particularly OA of the knee or hip. In general, findings from these studies suggest that chondroitin:

• Reduces OA pain
• Improves functional status of people with hip or knee OA
• Reduces joint swelling and stiffness
• Provides relief from OA symptoms for up to 3 months after treatment is stopped

However, the largest clinical trial so far, the 2006 Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), sponsored by the National Institutes of Health, showed conflicting and somewhat confusing results. The study of about 1,600 people with OA of the knee found that glucosamine and chondroitin did not reduce pain in the overall group, although it did appear to lessen pain among those with moderate-to-severe OA of the knee. The study has raised questions for further research. Since glucosamine and chondroitin were combined in this study, it is not possible to determine the effect of chondroitin alone. In addition, researchers are now studying whether the glucosamine-chondroitin combination may in fact help those with more severe OA.

Most studies have shown that chondroitin needs to be taken for 2 - 4 months before it shows effectiveness, although some improvement may be experienced sooner. Glucosamine and chondroitin can be used along with NSAIDs to treat OA.

Other

Other conditions for which chondroitin has been suggested include preterm labor, Alzheimer's disease, heart disease, and osteoporosis. However, no studies have yet evaluated these claims.

There are no significant dietary sources of chondroitin, so people who want to take it must take supplements.

Chondroitin is commonly sold as chondroitin sulfate in capsule or tablet form. It is often combined with glucosamine and sometimes manganese as well. Manganese is a trace element necessary for normal bone health. While the total amount of manganese from foods and supplements should not exceed 11 mg per day, several combination supplements for arthritis (containing glucosamine, chondroitin, and manganese) contain more than that. Read labels carefully, and consider choosing a supplement without manganese.

Pediatric

Chondroitin is not recommended for children. It is primarily used for treatment of osteoarthritis (a condition that affects adults), and its safety for children has not been studied.

Adult

400 mg three times a day or 600 mg two times a day, taken by mouth.

In the past, researchers have found that some chondroitin supplements, as well as some combination glucosamine and chondroitin supplements, did not contain the amount of chondroitin stated on the label. Ask your doctor to recommend a brand, or choose a brand you trust.

Many chondroitin supplements are made from cow cartilage. If you are a vegetarian, look for a supplement made from algae instead.

Side Effects

Chondroitin is safe and relatively free of side effects when used at the recommended daily dosage, at least for short periods of time. Some people may experience mild stomach upset. So far, few studies have investigated the safety and effectiveness of chondroitin when used for long periods of time.

Pregnancy and Breastfeeding

Pregnant and breastfeeding women should not take chondroitin, since it has not been studied for safety in these groups.

If you are currently being treated with any of the following medications, you should talk to your doctor before taking chondroitin:

Anticoagulants (blood-thinners) -- Because chondroitin is similar in chemical composition to heparin, a drug used to thin the blood, it is theoretically possible for chondroitin to increase the effects of blood-thinners.

Nonsteroidal anti-inflammatory drugs (NSAIDs) -- If you take NSAIDs to relive the pain associated with OA, taking chondroitin may reduce the dose of NSAIDs you need to take. Since NSAIDs can cause stomach bleeding, reducing the dosage can be helpful. Talk to your doctor, however, before starting to take chondroitin, since it can take several months before any improvements are felt.

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