Appetite & sugar hormone
GLP-1
Also searched as GLP-1.
You want it engaged: incretin signaling is a cornerstone of modern glucose and appetite control.
In depth
GLP-1 — the incretin hormone that sharpens glucose-dependent insulin release and signals satiety.
What drives it
Stomach emptying increases it.
The current data also demonstrate an enhancement in the postprandial GLP-1 response to the lunch following gastric treatment and to the later snack following duodenal targeting of hop extract. 10.1093/ajcn/nqab418. doi 10.1093/ajcn/nqab418
Gut barrier increases it.
SCFA/GLP-1 study 2015, Int J Obes — gut microbiota-derived short-chain fatty acids (e.g. propionate) stimulate GLP-1 (incretin) secretion from enteroendocrine L-cells via FFAR2/GPR43. PMC4356745. Mechanism: gut bacteria ferment non-digestible fiber in the colon into short-chain fatty acids, which act as signaling molecules binding FFAR2 (GPR43) and FFAR3 (GPR41) on enteroendocrine L-cells to trigger GLP-1 release. Separately, bacteria convert primary to secondary bile acids, which activate GPBAR1 and also release GLP-1. But the same bile acids apply a brake through a second receptor, and the knockout proves it: activation of intestinal FXR is inhibitory to GLP-1 release, reducing FFAR2 expression. SCFA-induced GLP-1 was blunted in colonic biopsies from FXR-agonist-treated mice and enhanced in FXR-knockout colonoids; FXR-KO mice showed elevated colonic FFAR2 mRNA and increased plasma GLP-1 on prebiotic supplementation. Two bile-acid receptors, opposite directions. A further paradox the authors name: propionate activates FFAR3, which couples to Gi/o and lowers cAMP — yet still enhances GLP-1, because it simultaneously engages intestinal gluconeogenesis and vagal afferent signaling. colonic L-cells; much of the causal work is mouse colonoids and knockouts, with human NCI-H716 L-cells in vitro. PMC4356745
Slows carb absorption increases it.
A counterintuitive lane, and the most useful kind. The L-cells that make GLP-1 live in the distal small intestine — so when α-glucosidase does its job efficiently, carbohydrate is absorbed high up and never reaches them. Inhibit the enzyme and large amounts of undigested carbohydrate arrive at the ileum, producing a long-lasting increase in GLP-1 secretion (PMC3653752; Expert Rev Endocrinol Metab 2014, DOI 10.1586/17446651.2014.931807). Acarbose also delays gastric emptying and augments CCK, GLP-1 and PYY, mainly by retarding carbohydrate absorption (PMID 11518688), and causality was tested directly with the GLP-1 receptor antagonist exendin(9-39) in a double-blind randomized crossover (PMID 33449919). Honest INCONSISTENCY: at least one trial found α-glucosidase inhibition failed to enhance GLP-1 or delay gastric emptying in type 2 diabetic patients (Diabet Med 2005;22:470-6), so the effect is well supported but not universal. Note also the contrast with DPP-4 inhibitors: α-glucosidase inhibitors raise GLP-1 while reducing plasma insulin and C-peptide — incretin enhancement without hyperinsulinemia. doi 10.1586/17446651.2014.931807 · PMID 11518688 · PMC3653752
What it drives
It increases Protects insulin cells.
GLP-1/beta-cell review 2013 — GLP-1 (incretin) receptor signaling potentiates glucose-stimulated insulin secretion from pancreatic β-cells via cAMP/PKA/Epac2 (glucose-dependent). PMC3556522
It increases Insulin sensitivity.
Drucker 2006, Cell Metab 3:153 — GLP-1 stimulates glucose-dependent insulin secretion from pancreatic β-cells.
It increases Curbs appetite.
Drucker 2006, Cell Metab 3:153 — GLP-1 inhibits food intake and promotes satiety via central and gastric actions.
It increases Gut-brain signal.
10.5009/gnl.2012.6.1.10 — GLP-1 and PYY act on the gut-brain axis by binding receptors in vagal afferents, as well as crossing the blood-brain barrier to reach CNS receptors and regulate POMC/CART and AgRP/NPY neurons directly — two parallel routes, neural and humoral. Vagal afferents terminate in the nucleus of the solitary tract, which relays to locus coeruleus, dorsal raphe and hypothalamus. doi 10.5009/gnl.2012.6.1.10
It reduces Fasting insulin.
insulin, fasting insulin, type 2 diabetes and blood lipids share one literature: heart, kidney, liver, and metabolic diseases share interlinked pathological mechanisms, including inflammation, oxidative stress, insulin resistance, and endothelial health issues. These four overlap by nature: fasting insulin is the level, insulin is the signaling, type 2 diabetes is the diagnosis and blood lipids are the substrate. The same driver legitimately reaches all four, and a reader should not mistake four arrows for four independent findings. doi 10.1038/s41581-026-01066-0 · PMC11725408
It reduces Type 2 diabetes.
insulin, fasting insulin, type 2 diabetes and blood lipids share one literature: heart, kidney, liver, and metabolic diseases share interlinked pathological mechanisms, including inflammation, oxidative stress, insulin resistance, and endothelial health issues. These four overlap by nature: fasting insulin is the level, insulin is the signaling, type 2 diabetes is the diagnosis and blood lipids are the substrate. The same driver legitimately reaches all four, and a reader should not mistake four arrows for four independent findings. doi 10.1038/s41581-026-01066-0 · PMC11725408
It increases Beta-cell renewal.
10.1159/000374027 — Verbatim: 'DYRK1A inhibitors are able to drive human beta cell proliferation in vitro and in vivo, an effect that can be further augmented by combined treatment with a number of GLP-1RAs, or TGF-beta superfamily antagonists' - harmine plus exendin-4 raised human beta-cell mass 700% versus 300% for harmine alone. the GLP-1 contribution here is as an AUGMENTER of a DYRK1A inhibitor, not as a regenerative agent on its own. doi 10.1159/000374027
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.