Insulin stimulates the uptake of glucose by skeletal muscle cell, where it can be used for energy or stored as glycogen (essentially a polymer of glucose molecules). The liver also stores glucose as glycogen during the absorptive period, and this is also stimulated by insulin. Primarily because the mass of skeletal muscle is greater than the liver, much more glycogan (75% of the total) is formed and stored in skeletal muscle. Blood glucose is also available for use by all cells of the body for energy during this period, but no other organ is capable of significant glycogen storage.