Amylin is a 37-amino-acid peptide hormone cosecreted with insulin from pancreatic β cells. In contrast to insulin, which controls plasma glucose concentrations primarily by increasing the rate of glucose disappearance, amylin appears to control plasma glucose via several mechanisms that reduce the rate of glucose appearance in plasma. By its effect on food intake, amylin limits nutrient inflow into the gut. By its effect on gastric emptying, it limits nutrient flux from gut to blood, and by its ability to suppress glucagon secretion, it is predicted to moderate the flux of glucose from liver to blood. Amylin is absolutely or relatively deficient in type I diabetes and in insulin-requiring type II diabetes. Amylin hormone replacement with an amylin agonist, such as the synthetic human amylin analogue, pramlintide, may, by mechanisms such as the preceding, assist in achieving metabolic control in individuals with type I and insulin-requiring type II diabetes.