Insulin is produced in the pancreas, a vital organ situated behind the stomach. Specifically, insulin is synthesized by the beta cells within the islets of Langerhans, clusters of cells that are responsible for regulating blood glucose levels. When blood sugar rises after eating, insulin is released to facilitate the uptake of glucose by cells, where it is used for energy or stored for future use. In diabetes, either the pancreas doesn't produce enough insulin or the body can't effectively use the insulin it produces, leading to elevated blood glucose levels and various health complications.