Leydig Cell Growth Supplement (LCGS) is a medium supplement designed for the optimal growth of normal Human Leydig Cells in vitro. It is a sterile, concentrated (100X) solution which contains growth factors, hormones, and proteins necessary for the culture of normal Human Leydig Cells. The supplement is formulated (quantitatively and qualitatively) to provide a defined and optimally balanced growth environment that maximally promotes the growth of Human Leydig Cells in vitro. The supplement is designed as an additive for Leydig Cell Medium (LCM, Cat. #4511) and should be used in conjunction with this medium. This product is for research use only. It is not approved for human or animal use, or for application in in vitro diagnostic procedures.