Use the ITS-A (Insulin-Transferrin-Selenium-Pyruvate) supplement as a basal medium supplement to reduce the amount of fetal bovine serum (FBS) required for culturing cells. ITS-A is used for adherent cell culture. Initially, ITS-A was used in combination with RPMI 1640 and Minimum Essential Medium (MEM). Nowadays, it is commonly used with other basal media to support a variety of cell types in the presence of 2–4% FBS.