Hyaluronic acid plays an integral role in maintaining and regulating moisture with the tissues and facilitates the transport of nutrients into the cells and the removal of metabolic waste. Hyaluronic acid is found in all of the body's tissue, with the highest concentrations located in the extracellular matrix of the skin and the synovial fluid that bathes the joints and cartilage. Optimum levels of hyaluronic acid are essential for the health of the joints and cartilage. Hyaluronic acid has undergone a natural enzyme cleaning technique for greater absorption. Whether hyaluronic acid ingested as a pill is able to easily enter joint tissue is not clear at this time.
Hyaluronic acid is a component of synovial fluid, and is found in the vitreous humor of the eye, the synovia of joints, and in subcutaneous tissue where it functions is as a cementing agent. Hyaluronic acid is a glycosaminoglycan with anti-inflammatory and anti-edematous properties. In osteoarthritis, changes occur in the this found in cartilage leading to degradation of the cartilage. Hyaluronic acid oral supplements are promoted for arthritis and many other conditions including skin health. I have come across one human study with an oral form of hyaluronic acid from chicken comb which showed some improvement in joint pain. Many studies have been conducted with this in the injectable form into knees and I have listed some of them below. Some of the studies with the injectable form of hyaluronic acid directly into the joint show it to be effective, while others have not shown much benefit.
Hyaluronic acid (also called Hyaluronan) is a component of connective tissue whose function is to cushion and lubricate. Hyaluronan occurs throughout the body in abundant amounts in many of the places people with hereditary connective tissue disorders have problems such as joints, heart valves and eyes. This abnormalities are a common thread in connective tissue disorders. Interestingly, they are also common biochemical anomalies in most of the individual features of connective tissue disorders such as mitral valve prolapse, TMJ, osteoarthritis, and keratoconus. Hyaluronic acid has been nicknamed by the press as the "key to the fountain of youth" because it has been noted that at least some people who ingest a lot of it in their diets tend to live to ripe old ages. ABC News had a show on a village in Japan and hyaluronic acid entitled, It should be noted that the people in the ABC news show were thought to get high amounts of HA from starchy root vegetables their natural diets. They were not taking supplements.