Chondroitin sulfate is a naturally occurring substance in the body. It is a major constituent of cartilage—the tough, elastic connective tissue found in the joints.

Based on the evidence of preliminary double-blind studies, chondroitin is widely used as a treatment for osteoarthritis, the typical arthritis that many people suffer as they get older. However, the supporting evidence for this use is weak.

There is some evidence that chondroitin might go beyond treating symptoms and actually protect joints from damage. Current medical treatments for osteoarthritis, such as nonsteroidal anti-inflammatory drugs(NSAIDs), treat the symptoms but don't actually slow the disease's progression, and they may actually make it get worse faster.1-5 Chondroitin (along with glucosamine) may take the treatment of osteoarthritis to a new level. However, more research needs to be performed to prove definitively that this exciting possibility is real.

Chondroitin is not an essential nutrient. Animal cartilage is the only dietary source of chondroitin. (When it's on your plate, animal cartilage is called gristle.) Unless you enjoy chewing gristle, you'd do best to obtain chondroitin in pill form from a health food store or pharmacy.