Insulin is the hormone that lowers blood glucose concentration in human physiology.
It is produced by beta cells in the pancreatic islets and released when blood glucose rises, such as after a meal. Insulin helps muscle and fat cells take up glucose and encourages the liver to store glucose as glycogen. It also reduces the liver’s release of newly produced glucose into the bloodstream.
Glucagon generally has the opposite effect, raising blood glucose when levels fall. Adrenaline and cortisol can also increase available blood glucose during stress, but they are not the main hormone responsible for lowering it. In diabetes mellitus, insufficient insulin production, impaired insulin action, or both disrupt glucose regulation. Insulin was first used clinically to treat diabetes in the early 1920s.