Collagen is the most abundant protein in the human body, found in the bones, muscles, skin, hair and tendons. It is the substance that holds the body together. Collagen forms a scaffold to provide strength and structure. Collagen is also found in many other body parts, including blood vessels, corneas and teeth.
You can think of it as the glue that holds all these things together. In fact, the word collagen comes from the Greek word “kólla,” which means glue.