When we eat, food eventually turns into glucose, the main source of energy for the millions of microscopic cells in our body. The only way for the cells to get this glucose is with insulin. Insulin is made by specialized beta-cells within the pancreas. The pancreas is a gland situated behind the stomach. It releases insulin into the bloodstream in response to the blood glucose rise after meals and snacks. Insulin is the key that unlocks the cell door to allow the glucose to enter where it is used for energy.