Joint Support. Double Strength. Important Joint Lubricant. With L-Proline, Alpha Lipoic Acid and Grape Seed Extract. Vegetarian / Vegan. Non-GMO. GMP Quality Assured. Hyaluronic Acid is a compound present in every tissue of the body, with the highest concentrations occurring in connective tissues such as skin and cartilage. Hyaluronic Acid is an important constituent or joint fluid, where it serves as a lubricant and plays a role in resisting compressive forces. L-Proline, Alpha Lipoic Acid and Grape Seed Extract have been included to create a more complete formula.