Chondroitin is found naturally in your body. It is a vital part of cartilage, giving it elasticity by helping it retain water. Studies have found that taking chondroitin can prevent cartilage breaking down and can also stimulate its repair mechanisms. In osteoarthritis, the cartilage in the joints breaks down. Taking chondroitin sulfate, one of the building blocks of cartilage, has been said to potentially slow this breakdown.