Sodium hyaluronate is the sodium salt of hyaluronic acid. Hyaluronic acid is found naturally in the fluid that bathes joints, in the vitreous humor of the eye and in the skin. It's abundant in the dermis of young skin, but levels of this important compound decline with age. This makes skin look older. Hyaluronic acid gives skin volume by holding onto water and as levels decline with age, skin loses its youthful fullness. As an anti-aging treatment, dermatologists inject it into the dermis of the skin to restore facial fullness in areas where volume is lost. Sodium hyluronate is the main ingredient in Restylane, an injectable filler used to treat loss of facial volume and wrinkles. It has other medical applications as well. Doctors sometimes use injections of sodium hyaluronate to treat knee pain due to arthritis. In this setting, it helps to lubricate the joint and reduce pain and