N-2 additive is based on Bottenstein's N-1 formulation and is a chemically determined serum-free additive. It is recommended to support the growth and expression of primary neuroblastoma and postmitotic neurons originating from the peripheral and central nervous systems. N-2 additive is provided as 100X concentrate and can be used with Neurobasal medium supplemented with growth factors such as bFGF and EGF. It can also be used with DMEM.