Nausea associated with GLP-1 agonists like semaglutide and tirzepatide may be due to receptors in primitive brain areas like the area postrema that trigger vomiting.

“he mentioned that you know some of the nausea associated with um OIC and mararo and things like that relates to the fact that there's um you know there are receptors for these things not just in one hypothalamic structure but also in like like area postma and areas of the brain that are these quote unquote primitive areas that are associated with um generating nausea when you need to rid yourself of a poison that you know nature conveniently uh engineered us with um with neurons that when they detect chemical changes in the blood make us vomit”