GLP-3 (Retatrutide) 15MG Research Vial - GLP-1/GIP/Glucagon Triple Receptor Agonist | Third-Party Tested

GLP-3 Research That Actually Gets Used

GLP-3 - the informal research designation for the triple receptor agonist compound structurally corresponding to Retatrutide (LY3437943), Eli Lilly's investigational multi-receptor agonist currently in Phase 3 clinical trials - represents the most advanced category of incretin-based metabolic research compound available for preclinical investigation. By simultaneously activating the GLP-1 (Glucagon-like peptide-1), GIP (Glucose-dependent insulinotropic polypeptide), and glucagon receptor pathways, GLP-3 type compounds allow researchers to study the combined and individual contributions of all three incretin and glucagon receptor systems to metabolic regulation in a single experimental design.

Helio Peptides operates differently from most research compound suppliers.

Every vial of GLP-3 goes through independent third-party testing at an ISO 17025-accredited laboratory before it ships - identity confirmed by HPLC, molecular weight verified by mass spectrometry, and assay content confirmed at the labelled 15MG. The Certificate of Analysis is available on request for every batch. At $89.95 per vial - or $80.96 in a pack of ten - this is one of the most rigorously documented sources of research-grade GLP-1/GIP/glucagon triple agonist material available from a US-based supplier. Researchers building comprehensive metabolic axis programmes may also be examining our Semaglutide research vial (GLP-1 monoagonist reference compound), our Tirzepatide vial (GLP-1/GIP dual agonist), and our MOTS-c 10MG Vial for complementary mitochondrial metabolic research.

What Is GLP-3?

GLP-3 is the informal research designation for a class of synthetic peptide compounds that function as triple agonists at the GLP-1 (Glucagon-like peptide-1) receptor, the GIP (Glucose-dependent insulinotropic polypeptide) receptor, and the glucagon receptor simultaneously. The compound structurally corresponding to Retatrutide (LY3437943) - Eli Lilly's investigational triple receptor agonist currently in Phase 3 clinical trials for obesity, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD) - is the primary reference compound in the GLP-3 research compound category.

The designation 'GLP-3' does not refer to a naturally occurring GLP-3 peptide (no canonical biological GLP-3 exists in the same sense as GLP-1 or GLP-2). Instead, it is a colloquial shorthand used in the research compound market to describe triple hormone receptor agonists, reflecting the three receptors targeted - GLP-1R, GIPR, and glucagon receptor (GCGR) - and distinguishing them from dual agonists like Tirzepatide (GLP-1/GIP) and monoagonists like Semaglutide (GLP-1 only). Eli Lilly itself uses the term 'triple agonist' rather than GLP-3 for Retatrutide.

Retatrutide (LY3437943) was designed to combine the complementary metabolic effects of three distinct hormonal signalling systems: GLP-1 receptor activation slows gastric emptying, suppresses appetite, and stimulates glucose-dependent insulin secretion; GIP receptor activation enhances insulin sensitivity, promotes adipose lipid metabolism, and potentiates GLP-1R signalling; glucagon receptor activation increases resting energy expenditure, stimulates hepatic glucose production, and promotes thermogenesis. The simultaneous activation of all three pathways is hypothesised to produce synergistic metabolic effects beyond what is achievable with single or dual agonism.

In Phase 2 clinical trial data published in The New England Journal of Medicine (2023), Retatrutide demonstrated mean body weight reduction of 17.5% at 24 weeks at the highest dose tested - a greater magnitude of weight reduction than previously published Phase 2 data for either Semaglutide or Tirzepatide at comparable timepoints. Phase 3 trials (TRIUMPH programme) are ongoing across multiple indications as of mid-2026.

The Helio Peptides GLP-3 vial is a synthetic peptide research material for controlled laboratory use - it is not the pharmaceutical investigational drug product being studied in Eli Lilly's clinical trials, and it is not intended for human administration. For researchers comparing GLP-1 axis agonist mechanisms, the full range includes our Semaglutide research vial (GLP-1 monoagonist, 28-amino acid GLP-1 analogue), our Tirzepatide vial (GLP-1/GIP dual agonist), and GLP-3 / Retatrutide analogue (GLP-1/GIP/glucagon triple agonist) - covering the complete spectrum of single, dual, and triple incretin receptor agonism.

How Does GLP-3 Work? Triple Receptor Agonism Explained

GLP-3 works by simultaneously binding to and activating three distinct G-protein coupled receptors - the GLP-1 receptor, the GIP receptor, and the glucagon receptor - each of which triggers separate but complementary downstream signalling cascades that collectively regulate appetite, glucose homeostasis, energy expenditure, and lipid metabolism.

GLP-1 Receptor (GLP-1R) Activation

GLP-1 receptor activation by GLP-3 stimulates glucose-dependent insulin secretion, inhibition of glucagon release, slowing of gastric emptying, and central appetite suppression through GLP-1R-expressing neurons in the hypothalamus and brainstem. GLP-1R is a class B GPCR that signals primarily through Gs-cAMP-PKA pathways in pancreatic beta cells, and through cAMP and MAPK pathways in neuronal tissues. This is the same receptor targeted by Semaglutide and Liraglutide - the established GLP-1 monoagonist class. In research settings, GLP-1R activation by GLP-3 provides the insulin secretagogue and anorectic component of its metabolic profile. Researchers studying isolated GLP-1R signalling can reference our Semaglutide research vial as the selective GLP-1R agonist reference compound.

GIP Receptor (GIPR) Activation

GIP receptor activation by GLP-3 enhances insulin sensitivity in peripheral tissues, promotes adipose lipid uptake and storage, potentiates GLP-1R-mediated insulin secretion, and modulates bone turnover. GIPR is also a class B GPCR, signalling through Gs-cAMP pathways in pancreatic beta cells and adipocytes. The GIPR component is the same receptor targeted by Tirzepatide (dual GLP-1/GIP agonist) alongside GLP-1R. In GLP-3 research, GIPR activation is studied for its contribution to the enhanced insulin sensitisation and lipid metabolic effects observed with triple versus dual agonism. Our Tirzepatide vial is the appropriate reference compound for studying the isolated GLP-1/GIP dual agonist profile.

Glucagon Receptor (GCGR) Activation

Glucagon receptor activation by GLP-3 stimulates increased resting energy expenditure, hepatic fatty acid oxidation, thermogenesis in brown adipose tissue, and hepatic glucose production. GCGR activation is the mechanism that differentiates triple agonists from dual GLP-1/GIP agonists - it adds an energy expenditure-promoting component to the appetitive and insulin-sensitising effects of GLP-1R and GIPR. In isolation, GCGR activation raises blood glucose (the classical glucagon counter-regulatory hormone response), but in the context of simultaneous GLP-1R and GIPR co-activation, this hyperglycaemic effect is suppressed while the energy expenditure and lipolytic effects are retained. This pharmacological balance is the central research hypothesis of triple agonist design.

Synergistic Multi-Receptor Signalling

The simultaneous activation of GLP-1R, GIPR, and GCGR by GLP-3 produces effects that are not simply additive but potentially synergistic - the three receptor systems interact at multiple levels including downstream signalling crosstalk, receptor internalisation and trafficking dynamics, and transcriptional programme co-regulation. Research applications include study of how triple receptor co-activation affects insulin/glucagon secretion ratios in isolated islet preparations, characterisation of GCGR-mediated hepatic gene expression in the context of concurrent GLP-1R and GIPR activation, and investigation of how triple agonist dosing shapes adipose versus hepatic versus muscle tissue metabolic gene programmes differently from single or dual agonist paradigms.

Research Applications

GLP-3 is investigated across multiple metabolic research directions reflecting the breadth of GLP-1R, GIPR, and GCGR biology. All applications below are for controlled laboratory environments only. This product is for research use only and is not for human or animal consumption.

Metabolic Syndrome and Obesity Research

The primary documented research application for GLP-3 is the study of multi-receptor incretin agonism in metabolic syndrome and obesity model systems. Published Phase 2 clinical data (NEJM 2023) demonstrated 17.5% mean body weight reduction with Retatrutide at 24 weeks - the highest magnitude of weight reduction reported in a Phase 2 obesity trial at the time of publication. Preclinical research using GLP-3 analogue compounds examines the mechanistic basis of this enhanced efficacy: whether it is attributable primarily to GCGR-mediated energy expenditure increase, GIPR-mediated enhanced insulin sensitivity, GLP-1R-mediated appetite suppression, or emergent properties of simultaneous tri-receptor engagement. Researchers may compare GLP-3 mechanisms with our Semaglutide research vial (GLP-1R monoagonist reference), our Tirzepatide vial (GLP-1R/GIPR dual agonist reference), and our AOD-9604 Vial for GH-fragment lipolysis mechanisms - building a comprehensive multi-compound metabolic research platform.

Hepatic Metabolism and MASLD Research

GLP-3's glucagon receptor component makes it a compound of particular interest in hepatic metabolism and metabolic dysfunction-associated steatotic liver disease (MASLD) research. GCGR activation in hepatocytes stimulates fatty acid oxidation, reduces hepatic lipid accumulation, and modulates the expression of genes governing hepatic gluconeogenesis and lipid metabolism. Combined with GLP-1R-mediated reduction in dietary lipid intake and GIPR-mediated improvement in peripheral insulin sensitivity (reducing hepatic de novo lipogenesis driven by hyperinsulinaemia), the triple agonist profile offers a multi-mechanism approach to studying hepatic steatosis in model systems. Retatrutide is in Phase 3 MASLD trials - making GLP-3 analogue research one of the most clinically proximate areas of preclinical investigation.

Comparative Incretin Receptor Pharmacology

A critical research application for GLP-3 is its use in systematic comparative studies alongside monoagonist and dual agonist reference compounds. By comparing the metabolic, transcriptional, and cellular effects of GLP-1R activation alone (Semaglutide), GLP-1R/GIPR dual activation (Tirzepatide), and GLP-1R/GIPR/GCGR triple activation (GLP-3/Retatrutide) in matched model systems, researchers can dissect the independent and synergistic contributions of each receptor to observed outcomes. This three-compound comparative design - using our Semaglutide research vial, Tirzepatide vial, and GLP-3 vial - is one of the most powerful experimental designs available for incretin receptor biology research in 2026.

Glucose Homeostasis and Pancreatic Islet Research

GLP-3's combined GLP-1R (insulin secretagogue, glucose-dependent) and GCGR (glucagon stimulation - normally counter-regulatory) activity in pancreatic islets provides a unique research model for studying how dual receptor co-activation in the same cell type (alpha and beta cells express both GLP-1R and GCGR) shapes the secretory dynamics of the endocrine pancreas. Research applications include isolated islet perfusion studies examining insulin/glucagon secretion ratios in response to GLP-3 versus mono and dual agonists, characterisation of receptor-specific desensitisation and internalisation dynamics in pancreatic beta cells, and investigation of how triple agonism shapes post-receptor signalling crosstalk between Gs and Gq pathways in islet cells.

Energy Expenditure and Thermogenesis Research

The glucagon receptor component of GLP-3 activates brown adipose tissue (BAT) thermogenesis and resting energy expenditure - a mechanism not present in GLP-1R or GIP receptor monoagonism and identified as a key contributor to the enhanced weight reduction observed with triple versus dual agonists. Research in this area examines GLP-3's effects on UCP1 expression in brown adipocytes, thermogenic gene programme activation in BAT and beige adipose tissue, and the interaction between GCGR-mediated thermogenesis and GLP-1R/GIPR-mediated reductions in energy intake. Researchers studying mitochondrial function and energy expenditure alongside GLP-3 may also be examining our MOTS-c 10MG Vial for AMPK-mediated metabolic adaptation and our SLU-PP-332 5MG Vial for ERR-mediated mitochondrial biogenesis - covering complementary molecular mechanisms of energy expenditure regulation.

Product Specifications

Purity Testing & Certificate of Analysis

Every batch of Helio Peptides GLP-3 is independently tested before release. Not sampled - every batch. Testing is conducted by an ISO 17025-accredited third-party laboratory:

• HPLC (High-Performance Liquid Chromatography): Confirms identity and purity at ≥99% - detects synthesis by-products and impurities against certified reference standards

• LC-MS (Liquid Chromatography-Mass Spectrometry): Confirms molecular identity against the Retatrutide-analogue structural reference - verifies sequence integrity and rules out synthesis artefacts

• Assay / Content Testing: Confirms the exact quantity of active GLP-3 peptide per vial matches the labelled 15MG

The COA for any specific batch is available on request. Email info@heliopeptides.com with your order number and batch details. Visit our Certificate of Analysis and Testing page for full testing methodology. Handling protocols are on our FAQ page.

How to Reconstitute GLP-3

GLP-3 is supplied as a lyophilised powder and is soluble in water. For working concentrations below 1 µg/mL, add 0.1% BSA to the reconstitution buffer to prevent adsorption to plastic surfaces.

1. Allow the vial to reach room temperature before opening

2. Add the required volume of bacteriostatic water or sterile PBS (pH 7.4) slowly along the inner vial wall using a sterile needle and syringe

3. Gently swirl until fully dissolved - do not shake or vortex

4. For working solutions below 100 ng/mL, add 0.1% BSA (bovine serum albumin) to prevent peptide adsorption to polypropylene surfaces

5. Inspect - clear and colourless. Discard if cloudiness or particulates are visible

6. Aliquot into single-use volumes and freeze at -80°C, or use immediately at 4°C within 24–48 hours

For complete reconstitution guidance, visit our FAQ page.

Storage Guidelines

• On delivery: refrigerate or freeze immediately

• Short-term (days to weeks): refrigerate at 4°C, away from direct light, in original sealed vial

• Long-term (months to years): freeze at -20°C to -80°C - optimal for extended peptide stability

• Avoid repeated freeze-thaw cycles: aliquot into single-use volumes before freezing

• Reconstituted solution: use within 24–48 hours at 4°C, or freeze aliquots at -80°C

Helio Peptides ships all vials with cold-chain packaging. Contact info@heliopeptides.com or call 1-855-435-4633 immediately if you have concerns about vial condition on arrival.

The Dosing Breakdown

The 15MG vial is a high-content research format suitable for both in vitro receptor characterisation and in vivo murine metabolic model systems. For institutional or wholesale pricing, contact our wholesale team directly.

How GLP-3 Fits the Helio Metabolic Research Lineup

When to choose GLP-3: Your research involves triple receptor agonism (GLP-1R + GIPR + GCGR), comparative incretin pharmacology spanning single/dual/triple agonist profiles, MASLD or obesity model systems where energy expenditure enhancement alongside appetite suppression is the experimental focus, or pancreatic islet research examining the insulin/glucagon secretion dynamics of simultaneous tri-receptor engagement.

When to also consider Semaglutide: Our Semaglutide research vial is the GLP-1R monoagonist reference compound - the essential comparator in any study characterising how adding GIPR and/or GCGR agonism modifies the baseline GLP-1R pharmacological profile.

When to also consider Tirzepatide: Our Tirzepatide vial is the GLP-1R/GIPR dual agonist - the intermediate comparator between GLP-1R monoagonism and GLP-1R/GIPR/GCGR triple agonism. The Semaglutide → Tirzepatide → GLP-3 comparison is the core experimental design in incretin receptor additivity research.

When to also consider MOTS-c: For metabolic research programmes examining mitochondrial energy expenditure alongside GLP-3's GCGR-mediated thermogenesis, our MOTS-c 10MG Vial provides AMPK-mediated metabolic regulation through a completely different mechanism - useful for dissecting receptor-dependent from receptor-independent energy expenditure pathways.

When to also consider SLU-PP-332: Our SLU-PP-332 5MG Vial activates ERR nuclear receptors to drive mitochondrial biogenesis and exercise-mimetic gene programmes - a transcriptional route to energy metabolism improvement complementary to GLP-3's receptor-mediated approach. Comparing receptor-mediated (GLP-3) versus transcriptional (SLU-PP-332) metabolic modulation in parallel designs is an emerging research direction.

When to also consider AOD-9604: Our AOD-9604 Vial is the GH fragment (176–191) studied specifically for lipolytic effects in adipose tissue - covering a GH-mediated fat metabolism mechanism complementary to GLP-3's GCGR-mediated hepatic and adipose metabolic effects.

Shipping & Fulfilment

Frequently Asked Questions

What is GLP-3?

GLP-3 is the informal research designation for synthetic peptide compounds that act as triple agonists at the GLP-1 receptor, GIP receptor, and glucagon receptor simultaneously. The primary reference compound in this class is Retatrutide (LY3437943), Eli Lilly's investigational triple hormone receptor agonist currently in Phase 3 clinical trials for obesity and type 2 diabetes. GLP-3 research compounds are used in preclinical laboratory settings to study multi-receptor incretin pharmacology - not for human administration.

What is the difference between GLP-1, GLP-2, and GLP-3?

GLP-1 (Glucagon-like peptide-1) is an endogenous incretin hormone that stimulates insulin secretion and suppresses appetite - the target of Semaglutide and other approved GLP-1 receptor agonists. GLP-2 is a separate endogenous peptide involved in intestinal mucosal growth and nutrient absorption, with no appetite or insulin effects. GLP-3 is not a naturally occurring peptide - it is an informal term used to describe synthetic triple receptor agonists like Retatrutide that activate GLP-1, GIP, and glucagon receptors simultaneously, reflecting their activity across three receptor systems.

What is Retatrutide and is GLP-3 the same compound?

Retatrutide (LY3437943) is Eli Lilly's investigational triple hormone receptor agonist targeting GLP-1R, GIPR, and glucagon receptors, currently in Phase 3 clinical trials. The Helio Peptides GLP-3 vial is a synthetic research material with structural characteristics corresponding to the Retatrutide triple agonist mechanism - it is not the pharmaceutical investigational drug product, is not FDA-approved, and is not intended for human use. Research-grade GLP-3 is intended strictly for laboratory research in controlled environments.

How does GLP-3 differ from Tirzepatide?

Tirzepatide is a dual GLP-1R/GIPR agonist - it activates two receptors. GLP-3 (Retatrutide analogue) activates three receptors: GLP-1R, GIPR, and additionally the glucagon receptor (GCGR). GCGR activation adds energy expenditure increase and hepatic fatty acid oxidation stimulation - effects not present with Tirzepatide alone. Phase 2 clinical data showed greater weight reduction with Retatrutide (17.5% at 24 weeks) than published Tirzepatide Phase 2 data at comparable timepoints. Our Tirzepatide vial is available as the dual agonist reference compound.

How does GLP-3 differ from Semaglutide?

Semaglutide is a GLP-1R monoagonist - it activates only the GLP-1 receptor. GLP-3 activates GLP-1R plus the GIP receptor and glucagon receptor. The additional GIPR component enhances insulin sensitivity and potentiates GLP-1R signalling; the GCGR component increases resting energy expenditure and hepatic lipid oxidation. Triple agonism produces significantly greater weight reduction in published comparative data. Our Semaglutide research vial is the reference compound for isolated GLP-1R pharmacology.

What does the glucagon receptor component of GLP-3 do?

Glucagon receptor (GCGR) activation increases resting energy expenditure by stimulating thermogenesis in brown adipose tissue, promotes hepatic fatty acid oxidation (reducing hepatic lipid accumulation), and stimulates hepatic glucose production. In isolation, GCGR activation raises blood glucose (classical counter-regulatory response) - but when co-administered with GLP-1R agonism (which stimulates insulin secretion), the hyperglycaemic effect is suppressed while the energy expenditure and lipolytic effects are retained. This pharmacological balance is the defining research hypothesis of triple agonist design.

Is GLP-3 the same as the GLP-3 natural peptide?

No. There is no canonical naturally occurring GLP-3 peptide in the biological sense of GLP-1 or GLP-2. 'GLP-3' in the research compound market is a colloquial shorthand for synthetic triple receptor agonists. Glucagon-like peptide processing from proglucagon produces GLP-1 and GLP-2, but not a defined GLP-3 peptide with established receptor. The term is used informally to describe triple agonist research compounds targeting three hormone receptor systems simultaneously.

What published clinical data exists on Retatrutide (the GLP-3 reference compound)?

Phase 2 data published in the New England Journal of Medicine (2023) demonstrated mean body weight reduction of 17.5% at 24 weeks with Retatrutide at the highest tested dose in adults with obesity - the largest published weight reduction for any GLP-based compound at that stage of development at the time of publication. Phase 3 TRIUMPH programme trials are ongoing as of mid-2026 across obesity, type 2 diabetes, MASLD, obstructive sleep apnea, and cardiovascular endpoints.

Is every batch of GLP-3 third-party tested?

Yes - every batch. ISO 17025-accredited laboratory testing using HPLC and LC-MS confirms identity, purity (≥99%), and assay content at 15MG. Visit our Certificate of Analysis page or email info@heliopeptides.com to request your batch COA.

How do I reconstitute GLP-3?

Reconstitute in bacteriostatic water or sterile PBS (pH 7.4). Add slowly along the inner vial wall, gently swirl until dissolved - do not shake. For working concentrations below 100 ng/mL, add 0.1% BSA to prevent adsorption to plastic. Full protocol on our FAQ page.

How should I store GLP-3?

Short-term: 4°C, away from direct light. Long-term: -20°C to -80°C. Avoid repeated freeze-thaw cycles - aliquot before freezing. Reconstituted solution: use within 24–48 hours at 4°C or freeze aliquots at -80°C.

Where is Helio Peptides GLP-3 manufactured?

Synthesised in the United States in a controlled US-based facility. USA made, USA tested, shipped same day with cold-chain packaging.

Does Helio Peptides ship internationally?

Contact info@heliopeptides.com or call 1-855-435-4633 for current international shipping availability. Domestic US orders: same-day dispatch, 1–3 business day delivery.

What payment methods are accepted?

Credit/debit card (3D Secure), bank transfer, Ethereum (ETH), Bitcoin (BTC), and USDC at locked exchange rates.

Is GLP-3 legal to buy in the USA?

GLP-3 (Retatrutide analogue) is sold as a research chemical for laboratory use only. It is not a scheduled controlled substance in the United States. It is not the pharmaceutical investigational drug product and is not FDA-approved for any indication. All purchases must comply with applicable federal and state laws. Buyers confirm research intent at checkout. Misuse or human administration is strictly prohibited.

Explore More From Helio Peptides

• Semaglutide Research Vial - GLP-1R monoagonist, the essential single-receptor reference for incretin comparison research

• Tirzepatide Vial - GLP-1R/GIPR dual agonist, the intermediate comparator between mono and triple agonism

• MOTS-c 10MG Vial - mitochondrial-derived peptide, AMPK-mediated energy metabolism complementary to GLP-3 GCGR thermogenesis

• SLU-PP-332 5MG Vial - pan-ERR agonist, exercise mimetic, transcriptional mitochondrial biogenesis research

• AOD-9604 Vial - GH fragment 176–191, lipolysis and adipose metabolism research

• Tesamorelin Vial - GHRH analogue, visceral adiposity and lipodystrophy research

• IGF-1 LR3 1MG Vial - downstream GH/IGF axis, anabolic and proliferative signalling research

• Certificate of Analysis & Testing - full explanation of ISO 17025 testing and how to read HPLC and LC-MS data

• Wholesale & Bulk Orders - institutional pricing for research programmes requiring consistent supply

All products sold on heliopeptides.com are intended solely for laboratory research and are not for human or animal consumption. These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. The Helio Peptides GLP-3 vial is not the Eli Lilly investigational drug product Retatrutide (LY3437943) and is not intended for clinical, diagnostic, or therapeutic use. By purchasing, the buyer confirms they are a qualified researcher and agrees to comply with all applicable federal and state laws. Not for sale to persons under the age of 21.