Chondroitin sulfate is a chemical found in human and animal cartilage. It is commonly used by mouth with glucosamine or other ingredients for osteoarthritis.

Chondroitin sulfate is one of the building blocks of cartilage. In osteoarthritis, the cartilage in the joints breaks down. Taking chondroitin sulfate might slow this breakdown. It is usually manufactured from animal sources, such as shark and cow cartilage. It can also be made in a lab.

Chondroitin sulfate is used for osteoarthritis and cataracts. It is often used together with other ingredients, including manganese ascorbate, hyaluronic acid, collagen peptides, or glucosamine. Chondroitin sulfate is also used for many other conditions, but there is no good scientific evidence to support these uses.

Uses & Effectiveness?

Cataracts. An injectable solution containing chondroitin sulfate and sodium hyaluronate is approved by the FDA to protect the eye during cataract surgery. It is not clear if using it in a different form will help.

Osteoarthritis. Taking chondroitin sulfate by mouth seems to provide some relief from osteoarthritis pain and improve function. High-quality, pharmaceutical-grade products have shown the most benefit. Chondrosulf (IBSA Institut Biochimique SA), Chondrosan (Bioiberica, S.A.), and Structum (Laboratoires Pierre Fabre) are examples of these products.

There is interest in using chondroitin sulfate for several other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: Chondroitin sulfate is likely safe when used for up to 6 years. It can cause some mild stomach pain and nausea. Other possible side effects include bloating, diarrhea, and constipation.

When placed into the eye: Chondroitin sulfate is possibly safe when used together with other ingredients in an eye drop.

There is concern that some chondroitin sulfate products are not labeled accurately. Some products might contain no chondroitin, while other products might contain more than the amount stated on the product's label. Because of these issues, the effects of different chondroitin products may vary. Speak with a healthcare provider to find out what dose or product might be best.