NOW? Hyaluronic Acid Joint Support Important Joint Jubricant With MSM 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 of joint fluid where it serves as a lubricant and plays a role in resisting compressive forces. Look for other fine NOW products in health food stores nationwide.