HA is a large hydrophilic molecule. When it is released from cells, it binds water, and this helps with hydration of the cells. It also attracts fluid into the synovial fluid of the joints and the vitreous fluid in the eye, hydrating and lubricating these areas. When it is produced by cells, HA is a long molecule with a high molecular weight. In this form, it binds to certain proteins produced by the immune system, such as IL-8, and prevents autoimmune responses and inflammation.[1]