An insulin analog (also called an insulin analogue) is any of several types of medical insulin that are altered forms of the hormone insulin, different from any occurring in nature, but still available to the human body for performing the same action as human insulin in terms of controlling blood glucose levels in diabetes. Through genetic engineering of the underlying DNA, the amino acid sequence of insulin can be changed to alter its ADME (absorption, distribution, metabolism, and excretion) characteristics. Officially, the U.S. Food and Drug Administration (FDA) refers to these agents as insulin receptor ligands (because, like insulin itself, they are ligands of the insulin receptor), although they are usually just referred to as insulin analogs or even (loosely but commonly) just insulin (without further specification).

These modifications have been used to create two types of insulin analogs: those that are more readily absorbed from the injection site and therefore act faster than natural insulin injected subcutaneously, intended to supply the bolus level of insulin needed at mealtime (prandial insulin); and those that are released slowly over a period of between 8 and 24 hours, intended to supply the basal level of insulin during the day and particularly at nighttime (basal insulin). The first insulin analog (insulin Lispro rDNA) was approved for human therapy in 1996 and was manufactured by Eli Lilly and Company.