Chondroitin is a simple 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 resilient by absorbing fluid (particularly water) into the connective tissue. It is also believed to block enzymes that break down cartilage and it provides the building blocks needed for cartilage to repair itself.

Based on clinical evidence, chondroitin may be an effective treatment for osteoarthritis (OA). OA is a type of arthritis caused by the inflammation, breakdown, and eventual loss of cartilage. Chondroitin supplements have been shown to decrease the pain of OA and slow the progression of the disease. Unlike current medical treatments for arthritis, such as ibuprofen and other NSAIDs (nonsteroidal anti-inflammatory drugs), chondroitin causes virtually no side effects. Also, many NSAIDs and pain relievers treat the symptoms of OA but do not slow the progression of the disease, and may cause serious side effects such as stomach bleeding from ulcers or other causes. Chondroitin is often taken with glucosamine, another supplement thought to be effective in treating OA.

Osteoarthritis

Results from several well-designed scientific trials 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:

• Significantly 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 discontinued 

Although some improvement may be experienced sooner, the full effectiveness of chondroitin generally begins after 2 to 4 months of use. Chondroitin may also be used along with NSAIDs in the treatment of OA.

Perhaps the most definitive results regarding the effectiveness of chondroitin for OA will be achieved with the ongoing Glucosamine/Chondroitin Arthritis Intervention Trial sponsored by the National Institutes of Health. This large-scale study involving over 1600 people is investigating the effects of chondroitin alone, glucosamine alone, or a combination of both for the treatment of knee OA. Results are expected in 2005.

Other

Other conditions for which chondroitin has been suggested include preterm labor, Alzheimer's disease, heart disease, and osteoporosis. For all of these conditions, it is much too early to tell if chondroitin is helpful or harmful. The role of chondroitin in each of these conditions is under various stages of scientific investigation.

The use of chondroitin as a therapy for OA (and other conditions) requires dietary supplements because the precise amount of chondroitin in foods is unknown. Meats with visible connective tissue may be sources of chondroitin, but the exact quantity of chondroitin present in such foods is unknown.

Chondroitin is commonly sold as chondroitin sulfate in capsule or tablet form. It is also available in combination with various forms of 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/or supplements should not exceed 11 mg/day, several combination supplements for arthritis [containing glucosamine, chondroitin, and manganese] contain more than that. Read labels carefullly.)

Chondroitin is not currently recommended for children. Because it is primarily used for treatment of osteoarthritis (a condition that affects older people), it is generally not used in children and its safety for children has not been studied.

400 mg twice a day or 800 mg once a day taken orally.

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable healthcare provider.

As with all supplements, the purity and concentration of chondroitin may vary from one product to another. Researchers at an independent laboratory that tests the purity of health, wellness, and nutrition products, discovered that more than half of the preparations of chondroitin, and combination products of glucosamine and chondroitin tested contained levels of chondroitin that were lower than what the label stated. As mentioned above, this same laboratory also detected levels of manganese in some chondroitin preparations that exceeded tolerable limits.

Chondroitin is safe and relatively free of side effects when used at the recommended daily dosage at least for short periods of time. Unfortunately, few studies have investigated the safety and effectiveness of chondroitin when used for long periods of time. Until the long-term use of chondroitin is deemed safe, it is best to consult a healthcare practitioner before taking chondroitin supplements.

Mild side effects of chondroitin reported in recent studies include diarrhea, constipation, and abdominal pain. There have been rare reports of swelling and accumulation of fluid in the eyelids and lower limbs, irregular heartbeats, and alopecia (hair loss) after taking the supplement.

Since the safety of chondroitin has not been widely studied, pregnant and breastfeeding women should refrain from using this supplement until more scientific evidence becomes available.

If you are currently being treated with any of the following medications, you should not use chondroitin without first talking to your healthcare provider.

Blood-thinning Medications

Chondroitin and heparin, a drug used to thin the blood, are similar in chemical composition. For this reason, some researchers speculate that people may suffer bleeding complications from chondroitin, particularly when it is used in combination with other blood-thinning medications, such as warfarin or heparin.

Cisplatin

Preliminary animal studies also suggest that chondroitin sulfate may reduce the kidney toxicity associated with cisplatin, a chemotherapy drug used for cancer treatment. Further studies are needed to determine whether chondroitin has the same effect in people taking cisplatin.

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Taking chondroitin supplements may result in a decreased need for NSAIDs such as ibuprofen to relieve the pain and swelling associated with OA. Because NSAIDs and aspirin can cause serious side effects, such as stomach bleeding and ulcers, chondroitin may be a useful adjunct or even alternative. Be sure to consult your healthcare provider before adding chondroitin to your healthcare regimen.

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