The early phase begins within minutes of eating, when nutrients in the upper gastrointestinal tract trigger neural and hormonal signals that stimulate L-cells even before food reaches the distal intestine
We have a lot more information toward the first question, and theres almost nothing toward the second question
Healthy weight loss maintenance with exercise, GLP-1 receptor agonist, or both combined followed by one year without treatment: A post-treatment analysis of a randomised placebo-controlled trial
A 2021 study in Nature Microbiology identified a protein (P9) secreted by Akkermansia that triggered GLP-1 release in mice (Yoon et al., 2021)
Semaglutide & Tirzepatide and other GLP-1RAs work primarily by making you sick
If the trajectory of every other GLP-1 medication tells us anything, it is that the gap between clinical promise and patient access can be vast, painful, and deliberately engineered