Collagen is a main structural protein in connective tissues of bone (1, 2), skin (1, 3, 2), tendons, ligaments (4, 2) and cartilage (2). Collagen forms a matrix which is responsible for the elasticity, firmness (4) and structural integrity (3) of those tissues. The peptides in collagen contain large amounts of the amino acids hydroxyproline, glycine and proline (3). Types of collagen supplements Collagen supplements are usually sold as hydrolysed collagen (a.k.a. collagen hydrolysate or collagen peptides. As its name implies, the peptides in the collagen have been broken down for easier absorption. They come in liquid, powder and capsule form. These supplements are easily digested and have good bioavailability…