Collagen is the most abundant protein in the human body and is a major component of the extracellular matrix (ECM). It is comprised of three polypeptide chains that are rich in hydroxy-proline amino acids and are twisted together into a triple-helical structure. Over 20 different types of collagen have been identified in humans; the main types are type I, II, and III; and together they make up 80% of the body’s collagen. Type I and III are important for wound healing.