Scrutinizing the poor beast, the scientists had a “eureka moment” when they discovered that anglerfish genes coded for several peptides related to the gut hormone glucagon. Scientists later identified that hormone as “glucagon-like peptide 1”—GLP-1. Further research showed that GLP-1 reduced blood sugar levels in mammals, making it a promising candidate for diabetes medication. The problem, however, was that the molecule’s half-life was much too short to serve as a useful medicine.

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When he studied the lizard’s venom, he discovered that its saliva contained a hormone called exendin-4, which worked much the same way as GLP-1, but lasted much longer.

If GLP-1 Drugs Are Good For Everything, Should We All Be on Them?

Derek Thompson's GLP-1 essay is a highly recommended read. He explores the genesis, explanations on why it works and posits if all of humanity will benefit from being on it.