Proline WHAT IS PROLINE? Proline (or L-Proline), is a non-essential amino acid the body can produce on its own. While it’s non-essential because our bodies can produce it, along with glycine, it essential for the synthesis of collagen, the most abundant protein in humans, being found in every cell throughout the body. Proline is the primary amino acid involved in the synthesis of collagen. Collagen is the main structural protein that constitutes all human connective tissues including skin, bones, joints, tendons, ligaments, veins, and arteries. Visit - https://www.nationalnutrition.ca/amino-acids/single-aminos/proline.html