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.