Hyaluronic Acid is formed by skin cells and is part of the connective tissue of the skin. One of its key functions is to retain moisture, and it has the ability to bind in between 1,000 and 10,000 times its own weight in water (i.e. one gram binds between one and ten liters). As we age, the skin's natural ability to produce Hyaluronic Acid depletes and wrinkles start to form and deepen.