Chondroitin sulfate is a naturally occurring acidic glycosaminoglycan found in the human and animal body.  Its main structure consists of repeating disaccharide units of D-glucuronic acid and N-acetylgalactosamine, modified by sulfation. It belongs to the glycosaminoglycan family and is an essential component of connective tissues such as cartilage, ligaments, skin, and blood vessel walls.

In the human body, chondroitin sulfate often combines with proteins to form proteoglycans, providing cartilage with excellent elasticity and compressive strength, thus helping to maintain normal joint function. Because it promotes cartilage repair, improves joint lubrication, and has anti-inflammatory effects, chondroitin sulfate is widely used in joint health supplements, pharmaceuticals, and functional foods.