GLP-1: the natural gut hormone behind Ozempic and all GLP-1 weight-loss drugs
A natural hormone released from the gut after eating that tells the pancreas to release insulin and signals the brain to reduce appetite; the parent molecule of all GLP-1-based diabetes and weight-loss drugs such as semaglutide and liraglutide. Not itself a drug, used as a research reference.
A researcher, an agent, or an algorithm wrote down the sequence and picked a target to hit.
An AI model like OpenFold3 or AlphaFold built a 3D structure and scored how well it fits the binding site.
A second contributor repeated the computation on their own hardware and the scores matched.
A chemistry service or a researcher ordered the sequence, it was manufactured, and mass spectrometry confirmed the right molecule was produced.
A binding or activity measurement confirmed that it actually does what the computer predicted — or didn't.
What this is
GLP-1(1-36) amide is the full-length form of glucagon-like peptide-1 — a 36-amino-acid fragment cut out of a larger precursor protein called proglucagon. It is not itself a drug, but it is the parent molecule of the entire GLP-1 receptor agonist class — liraglutide, semaglutide, dulaglutide, exenatide and their relatives — every one of which mimics or extends the action of the shorter, biologically active fragment GLP-1(7-36) amide that circulates in human blood after a meal. The sequence stored on this card (HDEFERHAEGTFTSDVSSYLEGQAAKEFIAWLVKGR) is the 36-residue primary fragment; in living tissue, the first six residues (HDEFER) are removed by prohormone convertases to yield the active GLP-1(7-36) form, and the C-terminus is amidated (–NH₂) — neither modification is visible in the raw one-letter sequence but both are essential for stability and receptor activity.
History
The existence of glucagon-like sequences within the proglucagon gene was revealed by molecular cloning of proglucagon in the early 1980s, but the physiological role of these "glucagon-like" peptides was not understood until later in the decade. Drucker and colleagues (1987) demonstrated that GLP-1 stimulates insulin gene expression and raises intracellular cyclic AMP in a rat islet cell line — the first direct molecular evidence that GLP-1 is a glucose-dependent incretin (Drucker, PNAS, 1987). The cloning of the human glucagon receptor (GCGR) by Macneil and colleagues (1994) mapped the receptor landscape through which proglucagon-derived peptides signal (Macneil, Biochem Biophys Res Commun, 1994). The structural determinants of how GLP-1 engages the transmembrane domain of its receptor were characterized by Yang and colleagues (2016), informing the rational design of long-acting analogs (Yang, J Biol Chem, 2016). Three decades of work on this hormone culminated in the GLP-1 receptor agonist class that now dominates type-2 diabetes and obesity pharmacotherapy.
What it does
GLP-1 acts at the GLP-1 receptor (GLP-1R), a class B GPCR expressed on pancreatic beta cells, gut vagal afferents, and neurons in the brainstem and hypothalamus. When blood glucose rises after a meal, GLP-1 released from intestinal L-cells stimulates insulin secretion in a strictly glucose-dependent manner — meaning it amplifies insulin release only when glucose is already elevated, which is why GLP-1-based therapies carry a low intrinsic risk of hypoglycemia. GLP-1 also slows gastric emptying, suppresses glucagon secretion from pancreatic alpha cells, and signals satiety to appetite-regulating centres in the brain. The full-length GLP-1(1-36) form represented on this card is the precursor; in vivo it is trimmed to GLP-1(7-36) amide, which is the principal circulating active form and the molecule most pharmacological research focuses on. The closely related peptide oxyntomodulin — also a proglucagon product — activates both GLP-1R and the glucagon receptor (GCGR), producing appetite suppression and increased energy expenditure through dual receptor engagement (Shankar, Diabetes, 2018; Pocai, Molecular Metabolism, 2014).
Evidence
- Human: GLP-1(7-36) amide and its synthetic long-acting analogs have been tested in thousands of human studies. The active fragment forms the pharmacological basis of every approved GLP-1 receptor agonist. Native GLP-1 infusion studies in humans have confirmed its glucose-dependent insulinotropic and appetite-suppressing effects. Shankar and colleagues (2018) used graded glucose-infusion procedures in overweight and obese subjects with and without type-2 diabetes to show that native oxyntomodulin — a related proglucagon product — has significant glucoregulatory effects independent of weight loss (Shankar, Diabetes, 2018).
- Animal: Extensively studied in rodent models of diabetes and obesity. GLP-1 receptor signaling in rat islet cell lines was among the earliest demonstrations of its insulin-stimulating mechanism (Drucker, PNAS, 1987).
- In vitro: Receptor-binding and signaling studies in recombinant cell systems have characterized GLP-1R engagement, including structural work on the seven-transmembrane binding domain (Yang, J Biol Chem, 2016) and earlier work identifying the closely related glucagon receptor through which related proglucagon peptides signal (Macneil, Biochem Biophys Res Commun, 1994).
Known effects
- Glucose-dependent insulin secretion — Well established; the defining incretin mechanism, demonstrated in vitro and in human infusion studies (Drucker, PNAS, 1987).
- Glucagon suppression — Documented in human studies; GLP-1 inhibits postprandial alpha-cell glucagon release.
- Slowed gastric emptying — Observed in human studies with GLP-1 infusion; contributes to postprandial glucose control.
- Appetite suppression and satiety signaling — Demonstrated in rodent and human studies; basis for the weight-management indication of GLP-1 receptor agonist drugs.
- Beta-cell cytoprotection — Preclinical evidence that GLP-1 receptor activation reduces beta-cell apoptosis and may help preserve beta-cell mass.
Mechanism
GLP-1(7-36) amide, the active processed form of this sequence, engages GLP-1R through a "two-domain" binding mode characteristic of class B GPCRs: the receptor's extracellular N-terminal domain captures the C-terminal portion of the peptide, while the seven-transmembrane bundle engages the peptide's N-terminal region (Yang, J Biol Chem, 2016). Receptor activation couples preferentially to Gαs, raising intracellular cAMP in pancreatic beta cells (Drucker, PNAS, 1987); the resulting PKA-dependent cascade closes ATP-sensitive potassium channels and triggers insulin exocytosis. In parallel, GLP-1R signaling recruits β-arrestin pathways involved in receptor internalization and cytoprotection. The N-terminal six residues (HDEFER) present in GLP-1(1-36) but absent from the active GLP-1(7-36) amide are inactive at GLP-1R; their removal by prohormone convertases is required for biological activity. Once formed, the active GLP-1(7-36) amide is itself rapidly degraded in circulation by dipeptidyl peptidase-4 (DPP-4), which cleaves the N-terminal two residues to yield GLP-1(9-36), a metabolite with little affinity for GLP-1R. This degradation gives the native peptide a plasma half-life of only 1–2 minutes — which is why all approved GLP-1 receptor agonist drugs are modified (by fatty-acid conjugation, Fc fusion, or backbone substitution) to resist DPP-4 cleavage.
Regulatory status
- US: GLP-1(1-36) itself is not a regulated drug product. It is a research and reference molecule and the parent of the GLP-1 receptor agonist class. Approved GLP-1 receptor agonist drugs — liraglutide, semaglutide, dulaglutide, exenatide, and others — are separately reviewed and regulated.
- WADA: Native peptide hormones that stimulate insulin secretion fall under WADA's prohibited list (S2, peptide hormones, growth factors, and related substances). GLP-1(1-36) as an endogenous peptide is present physiologically; pharmacological administration would be prohibited in sport.
Related peptides
- Glucagon (/card/pep-04430) — the other principal proglucagon-derived hormone, acting at GCGR to raise blood glucose. GLP-1 and glucagon are co-encoded in the same proglucagon precursor and processed differentially in pancreatic alpha cells (glucagon-dominant) and intestinal L-cells (GLP-1-dominant).
- Oxyntomodulin — a proglucagon-derived peptide that contains the full glucagon sequence and activates both GLP-1R and GCGR; studied for combined appetite suppression and increased energy expenditure through dual receptor engagement (Pocai, Molecular Metabolism, 2014; Shankar, Diabetes, 2018).
- GLP-1 receptor agonist analogs — liraglutide, semaglutide, dulaglutide, and exenatide are engineered to mimic or extend the action of GLP-1(7-36) amide. They differ in half-life, receptor-binding kinetics, and the fatty-acid or protein-fusion modifications that confer once-daily or once-weekly pharmacokinetics.
- GLP-2 — the adjacent proglucagon-derived peptide that acts at GLP-2R to support intestinal epithelial growth and barrier function; illustrates the multifunctional nature of proglucagon processing.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.7257048487663269 | openfold3-mlx |
| ranking score | 0.798628032207489 | openfold3-mlx |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 0.848 | global PDE — lower = better |
| disorder | 0.158 | fraction disordered |
| chain pair ipTM (A, B) | 0.726 | interface quality |
▸3-letter notation
▸recipeopenfold3-mlx 0.3.1
| parameter | value |
|---|---|
| model | openfold3-mlx 0.3.1 |
| weights | aedd8f3eb814e392… |
| hardware | apple_m4_base_16gb |
| mlx version | 0.31.1 |
| python | 3.14.3 |
| random seed | 42 |
| msa strategy | colabfold |
| diffusion samples | 1 |
| runtime | 468s |
| predicted by | mlx@peptide |
| predicted at | 2026-04-23 |
python3 openfold3/run_openfold.py predict --query_json {query.json} --runner_yaml examples/example_runner_yamls/mlx_runner.yml --output_dir {output_dir} --num_diffusion_samples 1 ▸citationbibtex
@peptide{pep10576,
sequence = {HDEFERHAEGTFTSDVSSYLEGQAAKEFIAWLVKGR},
target = {gcgr},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}