Mesoglycan is a type of substance found in many tissues in the body, including the joints, intestines, and the lining of blood vessels. Chemically, mesoglycan is related to the blood-thinning drug heparin and the supplement chondroitin. Unlike chondroitin, mesoglycan is primarily used to treat diseases of blood vessels. Preliminary evidence suggests that mesoglycan may be helpful for atherosclerosis, varicose veins, phlebitis, and hemorrhoids.

Mesoglycan is not an essential nutrient because the body usually manufactures it from scratch. For supplement purposes, mesoglycan is commercially extracted from the intestines of pigs. Very similar substances can be produced from cartilage, bone, and the lining of large blood vessels, and are often used interchangeably.