Glucagon-like peptide-1 (GLP-1) is secreted from intestinal L cells, and it promotes insulin secretion in a glucose-dependent manner by binding to the GLP-1 receptor (GLP-1R). GLP-1R belongs to a family of G-protein coupled receptors and it is highly expressed on pancreatic β cells and large ducts. Activating the GLP-1R has been shown to have beneficial effects on insulin secretion and the maintenance of beta cell glucose sensing, transcription, synthesis, proliferation, and survival. GLP-1R agonists are currently being investigated in connection with type 2 diabetes, obesity, and NASH.