Educational pathway discussion, no human-use angle. The headline distinction in the literature: semaglutide is a GLP-1 receptor agonist; tirzepatide engages both GLP-1 and GIP receptors (a dual agonist). Retatrutide goes further as a triple agonist.
What I find under-explained for newcomers is why "more receptors" is an active research question rather than an automatic "better." Anyone have a good review paper that lays out the incretin pathways without assuming a pharmacology degree? Let's build a reading list.