Smooth Muscle Cell Growth Supplement (SMCGS) is a medium supplement designed for the optimal growth of human primary smooth muscle cells in vitro. It is a sterile, concentrated (100X) solution which contains growth factors, hormones, and proteins necessary for the culture of normal human smooth muscle cells. The supplement is formulated (quantitatively and qualitatively) to provide a defined and optimally balanced growth environment that maximally promotes the growth of human primary smooth muscle cells in vitro. The supplement is designed as an additive for smooth muscle cell medium (SMCM, Cat. No. 1101) and should be used in conjunction with that medium.