By the way, doctor: Is there any drawback to hyaluronic acid capsules?
Q. I have been taking capsules containing hyaluronic acid for my knees. Is there any downside to this medication?
A. Hyaluronic acid, hyaluronate, and hyaluronan are different names for the same, viscous substance. Hyaluronic acid is one of the main ingredients of the synovial fluid that lubricates the joints. Part of the reason joints get arthritic is that the fluid starts to break down, so replenishing a bad knee with "fresh" hyaluronic acid makes some sense, and the FDA has approved injections of hyaluronic acid into the knee as a treatment for osteoarthritis. The injections are hardly a cure, but they're reasonably effective, providing about as much pain relief as taking an oral painkiller like ibuprofen or naproxen. Some injectable products (Hyalgan, Supartz, others) are made from "natural" hyaluronic acid derived from the combs of roosters; another (Synvisc) is made from a related synthetic substance called hylan G-F 20. It's not clear which is better.
From what we know, little if any hyaluronic acid gets to the knee if it's taken orally, so it's hard to see how capsules could have much of an effect. But many people swear by them, as they do for glucosamine. Since the only likely harm is to the pocketbook, I don't make much of a fuss about them.