To overcome the limited in vitro lifespan of keratinocytes in serum-free medium, a new basal medium that supports the long-term growth of human keratinocytes was developed.Called EpiLife, it is a basal nutrient medium that contains no proteins, hormones or unusual components.When used in conjunction with common supplements for serum-free keratinocyte growth, EpiLife greatly extends the lifespan of human keratinocytes when compared to other com. serum-free media.