Hyaluronic acid exists naturally in all living organisms and is a universal component of the spaces between the cells of body tissues (extracellular space). Hyaluronic Acid plays an important role in tissue hydration, lubrication and cellular function. Hyaluronic acid is an internal cosmetic to hydrate (moisturize) the skin with proven absorption and bioavailability. Hyaluronic acid moisturizes the skin from the inside out. Hyaluronic acid is for people who need to ease the flexing of their joints, especially their knees, by moisturizing their joints. Hyaluronic acid is for seniors who have established joint conditions.Basic Functions of Hyaluronic Acid. See the links below for more details.