Hyaluronic acid is a substance that is naturally present in the human body. It is found in the highest concentrations in fluids in the eyes and joints. The hyaluronic acid that is used as medicine is extracted from rooster combs or made by bacteria in the laboratory.

The FDA has approved the use of hyaluronic acid during certain eye surgeries including cataract removal, corneal transplantation, and repair of a detached retina and other eye injuries. It is injected into the eye during the procedure to help replace natural fluids. The FDA has also approved the use of hyaluronic acid for injection into the knee for patients with kneeosteoarthritis.

People use hyaluronic acid for various joint disorders, urinary tract infections (UTIs), acid reflux, dry eyes, vaginal pain, aging, and many other conditions, but there is no good scientific evidence to support these uses.