These cells are less proliferative than cell lines and have more complex requirements for nutrition. Primary cells also have a limited lifespan and reach towards senescence faster in culture conditions. Due to these special features, special media is a better choice for primary cell cultures and this calls for optimized basal media with supplementation. Specialty media are designed to be used with little or no serum component and supplemented with growth factors, lipids, and hormones. These components allow the proper optimization for growing the specific cell type.