Collagen is the most abundant protein in your body. It’s one of the major building blocks of bones, skin, muscles, tendons, and ligaments. Collagen is also found in many other body parts, including blood vessels, corneas, and teeth. It has various important roles, including providing structure to your skin and helping your blood clot. Studies show that hydrolysed collagen can help strengthen your joints and help with pain caused by conditions like osteoarthritis.