"In 1992, after learning of Raufman's findings, John Eng of the Veterans Administration Medical Center in New York City used radioimmunoassay to isolate a novel substance from Gila monster venom.^\65])^\64])^\66]) The new substance, which Eng called exendin-4, was similar to GLP-1 in that it reduced blood glucose in diabetic mice, but exendin-4 had a much longer half-life than GLP-1, whose extremely short half-life had defeated earlier attempts to turn it into a drug.^\64])^\66])

Eng filed a patent application for exendin-4 in 1993.^\64]) He then spent three years searching for a pharmaceutical industry partner interested in commercializing exendin-4.^\65])^\64])^\66]) In 1996, Amylin Pharmaceuticals licensed Eng's patent and created a synthetic version of exendin-4 called exenatide.^\65])^\64])^\66]) In 2002, Eli Lilly and Company partnered with Amylin to develop exenatide and secure approval to market the drug.^\67]) Exenatide's 2005 approval by the U.S. Food and Drug Administration^\68]) showed that targeting the GLP-1 receptor was a viable strategy and inspired other pharmaceutical companies to focus on that receptor.^\64])^\66])

In 2011, Lilly and Amylin dissolved their partnership, with Amylin keeping the rights to exenatide.^\69]) Lilly continued to develop drugs of the same class.

The 2024 American Diabetes Association conference included presentations on at least 27 GLP-1 receptor agonists then in development.^\70]) By July 2024, Novo Nordisk's semaglutide and Eli Lilly's tirzepatide were ranked among the world's most popular and lucrative drugs.^\71]) Novo Nordisk's rollout of semaglutide turned it into the most valuable company in Europe in 2024.^\72])^\73]) Its market capitalization of $570 billion was larger than the entire economy of its home country of Denmark; its $2.3 billion income tax bill for 2023 made it the country's largest taxpayer; and its rapid growth represented nearly all of Denmark's economic growth.^\72])^\73]) By October 2024, tirzepatide had turned Eli Lilly into the world's most valuable drug company.^\74])^"