In the 1980s, researchers identified a hormone in the human gut called GLP-1 that triggers the release of insulin, which controls blood sugar levels. The discovery would eventually launch a new class of diabetes drugs known as GLP-1 receptor agonists, the first of which was approved in 2005.
The drugs not only kept blood sugar in check. Curiously, they also seemed to suppress appetite, and some people taking them lost a modest amount of weight. The revelation led the US Food and Drug Administration to approve the first GLP-1 drug for weight loss in 2014. Called liraglutide and sold under the brand name Saxenda, the weekly injectable led to a