GLP-1 is secreted from the small intestine in response to ingestion of nutrients. It has a powerful insulinotropic effect and stimulates beta-cell growth and is therefore being developed for treatment of type 2 diabetes. The GLP-1 analogue, exenatide, is on the market in the USA as an add-on therapy. Another strategy to increase circulating GLP-1 is to inhibit the enzyme DPP-IV which degrades endogenous GLP-1. GLP-1-based therapy results in HbA1c reductions of approximately 1 percent point, and the lack of serious side effects and the low risk of hypoglycaemic episodes are unique traits.