An insulin analog is an altered form of insulin, different from the insulin secreted by the human pancreas, but still available to the human body for performing the same action as human insulin in terms of glycemic control. 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.

These modifications have been used to create two types of insulin analogs: those that are more readily absorbed from the injection site and are therefore acting faster than natural insulin injected subcutaneously, intended to supply the bolus level of insulin needed after a meal; and those that are released slowly over a period of between 8 and 24 hours, intended to supply the basal level of insulin for the day.