Updated on 6/20/2005
Hyaluronic acid (HA) is a naturally-occurring substance found in the body. It is a constituent of the synovial fluid that lubricates joints, allowing them to move over each other easily; and also of vitreous humor, the clear, jelly-like substance in the eye. Hyaluronic acid made from rooster combs (the Mokawk-like crown on a rooster's head) or from bacterial cultures is used medically to treat the pain of osteoarthritis in the knee when no other treatment has helped. People with arthritis tend to have lower than normal levels of hyaluronic acid. The treatment, called "viscosupplementation," involves injecting hyaluronic acid, usually in three to five shots over several weeks time.
If you're allergic to eggs, make sure to tell your doctor, so you can get bacterial HA in order to avoid an allergic reaction from the chicken-derived product. There are few side effects of treatment. Immediately after the shot, you may have some pain, warmth and swelling at the site of the injection, and it is best to avoid standing too long, jogging or heavy lifting for two days after getting the shot. HA injections don't work for everyone, but when they do, pain relief may last for several months. Although the injections are expensive, many insurance programs now cover them.
I'm aware of claims that oral supplements of HA can extend life, but I don't know of any scientific evidence that backs them up. I've also read about regions of Japan where many people live well into their nineties and seem to show few effects of aging despite such bad health habits as smoking and working outdoors without sunscreen. Supposedly, this is due to regular consumption of locally grown vegetables (mainly sweet potatoes and other root crops), whose special starches prompt the body to produce more hyaluronic acid. I don't believe it. And I know of no evidence that the HA supplements promoted on the Internet can help keep you stay young or, as advertised, preserve the health of your eyes, joints and skin.
Andrew Weil, M.D.