The organ in the human body that produces insulin is the pancreas. This glandular organ plays a crucial role in regulating blood sugar (glucose) levels through the secretion of insulin and glucagon. Insulin is a hormone that helps cells absorb glucose from the bloodstream for energy or storage. The pancreas contains clusters of cells known as the islets of Langerhans, which specifically produce insulin. Malfunction of the pancreas in insulin production can lead to diabetes mellitus, a condition that requires careful management of blood sugar levels for overall health. The pancreas thus has a pivotal role in metabolic regulation.