The GLP-1 signal

Tirzepatide also switches on the GLP-1 receptor, at about one fifth the strength of natural GLP-1, and it does so in a biased way that favours the cAMP pathway and leaves the receptor on the cell surface longer. In the brainstem and hypothalamus this quiets hunger and food noise. In the stomach it slows emptying, so a meal lasts longer. In the pancreas it makes beta cells release insulin only when glucose is high, so it lowers sugar without driving it too low.