L-Proline is an amino acid that is essential for the synthesis of collagen, the most abundant protein in mammals.  Collagen is the main structural protein that constitutes all human connective tissues, including skin, tendons, ligaments, joints, bone, and vasculature (veins and arteries).  L-Proline therefore provides building blocks that help to stabilize and strengthen the structural components of the body.  Although proline can be made in the body, low protein and vegetarian diets may not provide optimal support for the production of collagen. NOW® L-Proline is 100% vegetarian.Each capsule contains:L-Proline 500 mgNon-Medicinal Ingredients: Veg Capsule (hypromellose and water), Stearic Acid (vegetable source), and Silica. Adult Dosage: Take 1 capsule 2 times daily on an empty stomach.