How does Mounjaro work inside the body?

“GLP-1 analogues stimulate glucose-dependent insulin secretion, dampen inappropriately high glucagon secretion, slow gastric emptying and reduce food intake. GLP-1 acts within the gut–brain axis; indeed, although it reaches the brain via endocrine mechanisms, it also acts locally by activating GLP-1R present on the dendritic terminals of the vagus nerve that innervate the gut, thus mediating the inhibition of food intake as well as relaying the satiety signal to the brain. In the brain, GLP-1R expression is found in several nuclei in the hypothalamus that are involved in controlling food intake and body weight. Recently, the combination of GLP-1–mediated signalling pathways and the adipocyte hormone leptin has raised interest. Indeed, leptin could be an important biological signal by which GLP-1 interacts additively or synergistically to reduce food intake and body weight. This leptin–GLP-1 action may be mediated in part by common and complementary intracellular signalling pathways (phosphorylated signal transducer and activator of transcription 3 [STAT3], PTP1B). Beyond their hypoglycemic and metabolic effects, GLP-1–based therapies have demonstrated anti-inflammatory effects, with in vitro and in vivo accumulating evidence demonstrating that GLP-1 reduces levels of inflammatory markers. GLP-1–based therapies downregulate pro-inflammatory responses in inflammatory chronic-related diseases such as diabetes, vascular diseases, neurodegenerative brain disorders, non-alcoholic steatohepatitis, nephropathy and OA.”

From: Targeting the GLP-1/GLP-1R axis to treat osteoarthritis: A new opportunity? Jan 2022 Journal of Orthopaedic Translation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8888891/

Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist JCI Insight, 2020 https://pubmed.ncbi.nlm.nih.gov/32730231/