DMEM (Dulbecco's Modified Eagle Medium) was developed on the basis of MEM medium. Compared with MEM medium, its amino acid content is doubled, vitamin content is quadrupled, and non-essential amino acids, trace iron ions and sodium pyruvate have also been added. It is a widely used basal culture medium that supports the growth of various mammalian cell types. The original DMEM formulation contains a relatively low concentration (1 g/L) of glucose and sodium pyruvate. However, there are currently multiple formulations of DMEM, including those with higher glucose concentrations and those with or without sodium pyruvate. This medium contains a variety of components necessary for cell culture, such as amino acids, vitamins, and inorganic salts, but does not contain proteins, lipids, or growth factors. Therefore, it must be supplemented with serum or serum-free additives; typically 10%–20% fetal bovine serum (FBS) is added.