Insulin is a hormone that helps turn food into energy. Insulin is released by beta cells in the Islets of Langerhans -- there are about a million of these iselts, or islands inside your pancreas! After you eat, sugar from food goes into the bloodstream. Insulin unlocks body cells so they can accept a special delivery of sugar (aka glucose). The cell transforms glucose into energy for you to run and play. When these islets don't make insulin, that's called diabetes, and it's a big bummer to those folks who have it!