Hyaluronic acid (HA) is a glycosaminoglycan polysaccharide composed of repeating polymeric disaccharides of D-glucuronic acid and N-acetyl-D-glucosamine linked by β (1→3) bonds. In biology, it is widely distributed in prokaryotic and eukaryotic cells. In humans, it is abundant in the skin and present in the vitreous humor, umbilical cord, synovial fluid, skeletal tissue, heart valves, lungs, aorta, prostate, tunica albuginea, corpora cavernosa and spongiosum of the penis. It is produced mainly by mesenchymal cells, in addition to other types. An average 70-kilo man may have a total of 15 grams of hyaluronic acid in his body, a third of which is broken down and synthesized every day.