Glucose is a carbohydrate consisting of six carbon atoms and an aldehyde group. Glucose is used as a primary energy source in wide range of cell culture media including classical and serum-free media. It is one of the essential nutrients and is responsible for cell longevity and gene expression. High initial levels of glucose in the medium can contribute to an early boost in culture expansion but later results in formation of excess of lactic acid which lowers the pH of the medium causing stress and toxicity to the cells. High glucose concentration has shown to promote the proliferation of many tumor cell lines like HT29, MCF-7, MDA MB468. It also supports high cell growth in insect cell culture.