ITS-P supplement is a basal growth factor supplement used to reduce the serum requirements in reduced serum and serum free cell culture systems. ITS-P supplement is a basal growth factor supplement used to reduce the serum requirements in reduced serum and serum free cell culture systems. Insulin is a peptide hormone responsible for uptake, utilization and storage of glucose by cells. Insulin is often used as a medium supplement for cell culture in the range of 1-10mg/ml depending upon the cell type. Transferrin is a glycoprotein responsible for delivery of iron to cells. Most of the stimulatory activity of transferrin is attributed to its own iron binding properties. Transferrin has a stimulatory effect on many cell types and is used in cell culture at a concentration of 1-10mg/ ml. Selenium is an essential trace element required for normal cell growth and development. Sodium pyruvate is useful as an additional energy source since it is a key intermediate in the production of the high energy intermediate ATP within the cell.