GLP-1, GLP-2, GLP-3: Research on the GLP Receptor Class
Class research profile
The GLP-1 Class — GLP-1S, GLP-2T, and GLP-3R
Three generations of incretin-based research peptides. Single, dual, and triple receptor agonists. Compared head-to-head on mechanism, peer-reviewed outcomes, and analytical purity. HPLC-verified, COAs on every lot.
TL;DR. The GLP-1 class includes GLP-1S, GLP-2T, and GLP-3R, each studied in peer-reviewed GLP-1, GIP, and glucagon receptor research. Improved Peptides supplies these compounds for in vitro and laboratory research only — not for human consumption — with third-party COAs.
What is the GLP-1 class?
The GLP-1 class is a family of synthetic peptide research compounds that act as agonists at the glucagon-like peptide-1 (GLP-1) receptor. The class has expanded across three generations, each broadening the receptor scope:
| Generation | Compound | Receptor scope | Year of first synthesis |
|---|---|---|---|
| 1st | GLP-1S | GLP-1 receptor (single) | 2012 |
| 2nd | GLP-2T | GLP-1 + GIP (dual) | 2018 |
| 3rd | GLP-3R | GLP-1 + GIP + Glucagon (triple) | 2022 |
Each compound has been studied in peer-reviewed Phase 2 and Phase 3 trials for metabolic and incretin-pathway research. Improved Peptides supplies all three for in vitro and laboratory research only — not for human consumption.
Side-by-side comparison
| Dimension | GLP-1S | GLP-2T | GLP-3R |
|---|---|---|---|
| Class | GLP-1 single agonist | GLP-1/GIP dual agonist | GLP-1/GIP/Glucagon triple agonist |
| Half-life | ~165 hours (~7 days) | ~120 hours (~5 days) | ~150 hours (~6 days) |
| Mechanism scope | GLP-1 only | GLP-1 + GIP | GLP-1 + GIP + Glucagon |
| Phase status (2026) | Approved (the corresponding pharmaceutical GLP-1 product in clinical settings) | Approved (the corresponding pharmaceutical dual receptor agonist product in clinical settings) | Phase 3 ongoing |
| Notable Phase 2 outcome | STEP/SELECT/SUSTAIN trial program | SURPASS/SURMOUNT trial program | Phase 2 body-composition outcomes published in 2023 (Jastreboff et al., NEJM) |
| Research interest trend | Plateau — well-characterized | Rising — extensive recent literature | Steep rise — newest, most actively studied |
| Improved Peptides purity | HPLC 99%+ | HPLC 99%+ | HPLC 99%+ |
| Product page | Shop GLP-1S | Shop GLP-2T | Shop GLP-3R |
| Research profile | GLP-1S research | GLP-2T research | GLP-3R research |
Mechanism deep dive
GLP-1S — GLP-1 single agonism
GLP-1S is a long-acting analog of human GLP-1 with a fatty-acid side chain that extends its plasma half-life via albumin binding. It binds selectively to the GLP-1 receptor, modulating glucose-dependent insulin secretion, gastric emptying, and central appetite signaling pathways studied in incretin research.
GLP-2T — GLP-1 + GIP dual agonism
GLP-2T is a 39-amino-acid synthetic peptide engineered to activate both the GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors. The dual-agonist design has been studied for additive effects on insulin sensitivity, lipolysis, and energy expenditure beyond GLP-1 monotherapy.
GLP-3R — GLP-1 + GIP + Glucagon triple agonism
GLP-3R is the third-generation tri-agonist, adding glucagon receptor activity to the GLP-1/GIP combination. Glucagon-receptor signaling has been studied for its role in hepatic energy metabolism and basal metabolic rate. Phase 2 data (Jastreboff et al., 2023) reported the largest body-composition changes observed across the class.
Citations (peer-reviewed, PubMed-linked)
GLP-1S
- Marso SP, et al. SUSTAIN-6: Cardiovascular Outcomes Trial in Type 2 Diabetes. NEJM. 2016. PMID: 27633186
- Wilding JPH, et al. STEP 1: Once-Weekly GLP-1 Agonist Trial for Overweight or Obesity. NEJM. 2021. PMID: 33567185
- Davies M, et al. STEP 2: Once-Weekly GLP-1 Agonist Trial for Overweight or Obesity in Type 2 Diabetes. Lancet. 2021. PMID: 33667417
- Lincoff AM, et al. SELECT: Cardiovascular Outcomes Trial in Obesity without Diabetes. NEJM. 2023. PMID: 37952131
GLP-2T
- Frias JP, et al. SURPASS-2: GLP-1/GIP vs. GLP-1 Head-to-Head Trial in Type 2 Diabetes. NEJM. 2021. PMID: 34170647
- Jastreboff AM, et al. SURMOUNT-1: Once-Weekly GLP-1/GIP Dual Agonist Trial for Obesity. NEJM. 2022. PMID: 35658024
- Rosenstock J, et al. SURPASS-1: GLP-1/GIP Dual Agonist Monotherapy Trial in Type 2 Diabetes. Lancet. 2021. PMID: 34186022
- Karagiannis T, et al. GLP-1/GIP Dual Agonist vs. GLP-1 RAs: Systematic Review & Meta-Analysis. BMJ. 2022. PMID: 35338814
GLP-3R
- Jastreboff AM, et al. GLP-1/GIP/Glucagon Triagonist: Phase 2 Obesity Trial. NEJM. 2023. PMID: 37354450
- Rosenstock J, et al. GLP-1/GIP/Glucagon Triagonist: Phase 2 Trial in Type 2 Diabetes. Lancet. 2023. PMID: 37356449
- Sanyal AJ, et al. GLP-1/GIP/Glucagon Triagonist: Phase 2 Trial in MASLD. Lancet GH. 2024. PMID: 38663433
Quality and verification
Every batch of GLP-1S, GLP-2T, and GLP-3R is independently tested by a third-party laboratory using:
- HPLC — for purity (target 99%+)
- Mass spectrometry — for sequence confirmation
- UV spectroscopy — for concentration verification
Current batch COAs are published in our COA Library and linked from each product page. Every lot is traceable. For the full analytical methodology behind these results, see our testing standards; for how batch documentation fits a broader supplier-vetting framework, see our guide to evaluating research peptide vendors.
Storage and reconstitution (research reference)
| Stage | Condition |
|---|---|
| Lyophilized vial (shipping) | Room temperature, stable for 2-3 weeks |
| Lyophilized vial (long-term) | Refrigerator (2-8°C) for 6-12 months; freezer (-20°C) for 24+ months |
| Reconstituted (with bacteriostatic water) | Refrigerated, use within 28 days |
Reconstitution solvent: Bacteriostatic water with 0.9% benzyl alcohol. Available at /shop/bacteriostatic-water/.
Choosing between the three (research framework)
Researchers selecting between GLP-1S, GLP-2T, and GLP-3R typically evaluate four axes:
- Mechanism scope: Single (GLP-1S) → Dual (GLP-2T) → Triple (GLP-3R) receptor activation
- Published outcome magnitude: Phase 2 body-composition data trends GLP-3R > GLP-2T > GLP-1S
- Research history: GLP-1S has the longest published record; GLP-3R has the newest
- Cost-per-mg: GLP-1S lowest, GLP-3R highest at current market rates
The choice depends on the research question being investigated. All three are stocked, HPLC-verified, and ship same-day on orders before 2pm ET.
FAQ
Q: What is the GLP-1 class?
A: A family of synthetic peptide research compounds that activate the GLP-1 receptor. The class has expanded to include dual (GLP-1/GIP) and triple (GLP-1/GIP/Glucagon) receptor agonists.
Q: What is the difference between GLP-1S, GLP-2T, and GLP-3R?
A: GLP-1S is a single GLP-1 agonist. GLP-2T is a dual GLP-1 + GIP agonist. GLP-3R is a triple GLP-1 + GIP + Glucagon agonist. They differ in receptor scope, half-life, and the breadth of peer-reviewed published research.
Q: Where do I find peer-reviewed citations?
A: Citations for all three compounds are listed in the section above with direct PubMed links. We update the citation list as new peer-reviewed research is published.
Q: What purity standard does Improved Peptides verify?
A: HPLC-tested 99%+ purity, sequence-confirmed by mass spectrometry, with a COA from an independent third-party lab on every batch.
Q: Are these peptides legal to purchase?
A: All compounds offered by Improved Peptides are sold strictly for in vitro and laboratory research use. They are not for human consumption, diagnosis, or treatment.
Q: Which GLP-1 compound has the most published research?
A: GLP-1S currently has the longest and most extensive published record, with GLP-2T rapidly expanding. GLP-3R is the newest and has the most active research pipeline.
Q: How is the Wolverine Stack different from the GLP-1 class?
A: The Wolverine Stack is a tissue-repair research combination (BPC-157 + TB-500). The GLP-1 class is a metabolic/incretin research family. Different mechanisms, different research applications.
Q: What other metabolic research peptides does Improved Peptides catalog?
A: Beyond the GLP-1 class, several compounds are studied in metabolic and body-composition research through distinct mechanisms: Tesamorelin, a GHRH analog studied in the growth-hormone axis; MOTS-c, a mitochondrial-derived peptide studied for AMPK-pathway signaling; and 5-Amino-1MQ, an NNMT-pathway research compound. Each acts on a different target than the incretin-receptor agonists in the GLP-1 class.
Ready to source the GLP-1 class?
All three compounds — GLP-1S, GLP-2T, and GLP-3R — are stocked, HPLC-tested, and ship same-day on orders before 2pm ET.
Shop GLP-1S | Shop GLP-2T | Shop GLP-3R | View All Class Components
About this research overview. This article summarizes published peer-reviewed literature on this compound for research-use-only context. Improved Peptides products are research compounds and are not drugs, supplements, or foods. They are not intended for human or animal consumption. Citations link to the original studies for independent verification.