Collagen is the most abundant protein in the body — the primary building block of skin, muscles, bones, tendons and ligaments. It also appears in blood vessels, organs and the intestinal lining.
It is built around three amino acids — proline, glycine and hydroxyproline — folded into a triple helix, with vitamin C, zinc and copper as the cofactors the body needs to assemble it. In short: collagen gives skin its strength and elasticity, and keeps connective tissue resilient throughout the body.