Collagen is a protein that keeps your bones strong and allows your skin to stretch and heal after injuries. One of the reasons we get wrinkles as we age is because we gradually lose collagen.
Collagen is the most common protein in all mammals, including humans, and it's an important one, as it helps keep us strong and healthy. The word comes from a Greek root, kolla that means "glue." Most collagen is found in the connective tissue between our bones, and its loss can result in achy joints. Some people believe that taking collagen supplements (made from tissue and bones of animals) can improve their health and reduce this pain.