About Retatrutide
Retatrutide is a synthetic 39 residue peptide designed to act as a single molecule agonist at three separate receptors, the glucagon receptor, the glucose dependent insulinotropic polypeptide receptor and the glucagon like peptide 1 receptor. Its sequence incorporates alpha aminoisobutyric acid residues that resist enzymatic breakdown, together with a twenty carbon diacid chain attached through a lysine side chain that supports reversible albumin binding. Peptsche supplies it as a lyophilized powder sealed in a single use glass vial, a format stable through transport and cold storage. Peptsche supplies Retatrutide strictly as a research material for controlled laboratory investigation.
Available Sizes
This listing covers two vial configurations. Every lot is assayed before release, so the stated purity applies to the batch shipped.
- 5mg vial of lyophilized Retatrutide, 99% or greater purity by HPLC
- 10mg vial of lyophilized Retatrutide, 99% or greater purity by HPLC
Product Specifications
| Product | Retatrutide (LY3437943) |
| Application | Research use only. Laboratory and in vitro investigation. |
| Appearance | White to off white lyophilized powder |
| Chemical Formula | C221H342N46O68 |
| Molecular Weight | approximately 4731 g/mol. No pharmacopoeial monograph exists for this compound, so a precise value to two decimal places is not available from an authoritative source. |
| CAS Number | 2381089-83-2 |
| PubChem CID | 171390338 |
| Sequence | A 39 residue triple receptor agonist peptide incorporating alpha aminoisobutyric acid residues and a C20 diacid modified lysine, one letter YAQGTFTSDYSILLDKKAQAAFIEYLLEGGPSSGAPPPS with a C terminal amide |
| Synonyms | LY3437943 |
| Purity | 99% or greater by HPLC, verified per batch |
| Storage | Store sealed at 2 to 8 °C, protected from heat, light and moisture |
| Regulatory Status | Investigational compound in Phase 3 clinical development by Eli Lilly and Company. Not approved as a medicine in any jurisdiction. Not approved for human or veterinary use. |
What is Retatrutide?
Retatrutide sits in a class of engineered peptides described as unimolecular polyagonists, where one chain is tuned to satisfy the binding requirements of several related receptors at once. The three targets belong to the class B G protein coupled receptor family and share evolutionary ancestry, which is what makes a single sequence capable of engaging all of them.
Structurally the peptide carries alpha aminoisobutyric acid substitutions that stabilise helical geometry and blunt proteolytic cleavage, and a twenty carbon diacid attached through a lysine side chain. That lipid modification binds serum albumin reversibly and is the feature investigators cite when describing the extended circulating presence measured in animal work.
The published record consists of discovery pharmacology and clinical trials conducted by Eli Lilly and Company, the originator. Those findings describe the investigational molecule as studied by its developer under regulated conditions and do not characterise the research grade material offered here. Peptsche makes no claim that this compound produces any outcome in a human or animal subject.
Retatrutide Mechanism of Action (Research Only)
Mechanistic interest centres on the fact that three receptor activities are combined in one chain. The summaries below describe reported receptor level observations, not effects in humans.
Simultaneous Agonism at Three Receptors
The compound activates the glucagon receptor, the glucose dependent insulinotropic polypeptide receptor and the glucagon like peptide 1 receptor. All three couple through stimulatory G protein to adenylate cyclase, so cyclic adenosine monophosphate accumulation serves as the common readout across all three assays. Coskun and colleagues characterised relative potency at each receptor in transfected cell systems and reported an unbalanced rather than equal profile across the three targets.
Structural Basis of Triple Receptor Engagement
Designing one sequence to satisfy three binding pockets requires compromise at positions that differ between the receptors. The reported approach combines residues drawn from the native ligands of each receptor with unnatural amino acid substitutions at cleavage sensitive positions. Mutagenesis work examines which residues drive selectivity, making the compound a probe for how this receptor family discriminates between related ligands.
An Investigational Compound with No Approved Reference
Unlike molecules with an approved counterpart, Retatrutide has no marketed reference product against which laboratory material can be compared. Receptor pharmacology groups use it to ask how a triple agonist profile differs from dual and single agonist ligands in the same assay, and comparisons must rest on published receptor data rather than a pharmacopoeial standard.
Integrated Mechanistic Profile
The published literature describes Retatrutide through three connected themes.
- Triple receptor engagement. Agonism at glucagon, glucose dependent insulinotropic polypeptide and glucagon like peptide 1 receptors from one entity.
- Structural compromise. Unnatural residue substitution and a C20 diacid chain supporting reversible albumin binding.
- Investigational status. No approved reference product, so characterisation rests on published receptor pharmacology.
Note: Retatrutide is supplied strictly for research use only. It is intended as an experimental compound for qualified laboratory personnel and is not a drug, food or cosmetic.
Retatrutide is supplied exclusively for laboratory research use and is not intended for human or veterinary application.
Research Applications (Observations from Studies)
The areas below describe reported research uses.
Multiplexed Receptor Signalling Assays
The characteristic experiment runs three parallel cell lines, each expressing one target receptor, and compares concentration response curves side by side. Reported endpoints include cyclic adenosine monophosphate accumulation, competition binding constants and beta arrestin recruitment.
Comparative Polyagonist Pharmacology
The compound is frequently placed alongside single and dual receptor agonists to ask what the third receptor activity contributes in a defined assay. Observations from that work belong to the systems and conditions described in each publication.
Analytical Method Development
Laboratories building chromatographic or mass spectrometric methods for acylated peptides use material of this kind to establish retention and fragmentation behaviour. Because no pharmacopoeial monograph exists, method work relies on the batch certificate of analysis rather than an official standard.
Retatrutide is supplied exclusively for laboratory research use and is not intended for human or veterinary application.
Retatrutide Compared With Related Research Compounds
The table below places Retatrutide alongside two related compounds in the Peptsche range. It is offered to clarify differences in classification, molecular target and research context. It should not be read as a comparison of clinical performance, safety, or suitability for any application.
| Characteristic | Retatrutide | Tirzepatide | AOD-9604 |
| Research Classification | Synthetic 39 residue peptide acting as a triple glucagon, GIP and GLP-1 receptor agonist | Synthetic 39 residue peptide acting as a dual GIP and GLP-1 receptor agonist | Synthetic sixteen residue cyclic analogue of a carboxy terminal region of human growth hormone, not an incretin receptor ligand |
| Primary Molecular Target | Glucagon receptor, glucose dependent insulinotropic polypeptide receptor and glucagon like peptide 1 receptor | Glucose dependent insulinotropic polypeptide receptor and glucagon like peptide 1 receptor | No defined receptor target. Examined through the lipolytic domain hypothesis in adipose tissue preparations |
| Mechanistic Profile | Simultaneous agonism at three related class B G protein coupled receptors, reported as an unbalanced rather than equal profile | Dual incretin receptor agonism from one molecular entity, with cyclic adenosine monophosphate accumulation as the usual assay readout | Reproduces a discrete carboxy terminal domain of the parent hormone while omitting its growth promoting region, a route entirely separate from incretin receptor agonism |
| Primary Research Focus | Multiplexed receptor signalling assays, comparative polyagonist pharmacology, analytical method development | Receptor binding and cell based signalling assays, islet and adipocyte culture systems, analytical reference work | Adipose tissue and metabolic assays, animal joint tissue models, analytical detection and in vitro metabolism |
| Structural Design | 39 residues with alpha aminoisobutyric acid substitutions and a C20 diacid modified lysine, C terminal amide | 39 residues with two alpha aminoisobutyric acid substitutions and a C20 diacid chain on a lysine side chain, C terminal amide | Sixteen residues closed by a disulfide bridge between cysteines at positions 7 and 14, with a synthetic amino terminal tyrosine |
| Regulatory Status | Investigational compound in Phase 3 clinical development by Eli Lilly and Company. Not approved as a medicine in any jurisdiction and not approved for human or veterinary use | The molecule is the active ingredient in approved medicines marketed as Mounjaro and Zepbound by Eli Lilly and Company. Material supplied is research grade, is not those medicines, and is not approved for human or veterinary use | Research use compound, not approved for human or veterinary use in any jurisdiction, and appearing among the bulk drug substances withdrawn from consideration for compounding by the United States Food and Drug Administration |
Retatrutide is supplied exclusively for laboratory research use and is not intended for human or veterinary application.
Laboratory Handling and Storage Considerations
Lyophilized Retatrutide should be stored sealed at 2 to 8 °C, protected from heat, light and moisture. The powder is hygroscopic, so vials should reach ambient temperature before opening to prevent condensation onto the cake. Acylated peptides of this class are surface active and can adsorb to plastic, so low binding labware is commonly selected. Prepared solutions should be aliquoted rather than cycled through freezing and thawing, and every container should carry identity, lot number and preparation date.
Laboratory Safety Considerations
The practices below apply to routine handling in a research setting.
- Personal protective equipment: Wear nitrile gloves, a laboratory coat and safety glasses whenever a vial is open.
- Engineering controls: Weigh and prepare solutions in a certified fume hood to limit powder dispersal.
- Exposure prevention: Avoid skin, eye and mucous membrane contact and wash hands afterwards.
- Storage: Keep sealed vials at 2 to 8 °C in a dedicated research chemical location.
- Spill response: Collect spilled powder without raising dust and treat residue as chemical waste.
- Disposal: Discard unused material and contaminated consumables through the institutional chemical waste stream.
- Documentation: Record lot number, receipt date and each preparation so results stay traceable to a batch.
Certificate of Analysis and Quality Assurance
Every production lot of Retatrutide supplied by Peptsche undergoes analytical evaluation, and a batch specific Certificate of Analysis accompanies each order to support research documentation, quality control and experimental consistency.
Each Certificate of Analysis typically includes:
- Identity verification using analytical techniques such as mass spectrometry to confirm the molecular characteristics of the material supplied.
- Purity analysis performed by high performance liquid chromatography to quantify purity and identify potential impurities.
- Batch documentation recording lot number, testing date, analytical methods applied and quality assessment results.
- Traceability information to support laboratory recordkeeping and reproducibility across research workflows.
Peptsche works with Janoshik Analytical, an independent testing laboratory, for third party verification of research material quality. Independent testing provides transparency and confidence in product identity, consistency and sourcing, and batch specific documentation can be retained as part of laboratory records and internal quality procedures.
Retatrutide is supplied exclusively for laboratory research use and is not intended for human or veterinary application.
Frequently Asked Questions
What is Retatrutide?
Retatrutide is a synthetic 39 residue peptide designed to act as a single molecule agonist at three separate receptors. It is an investigational compound in Phase 3 clinical development by Eli Lilly and Company, is not approved as a medicine in any jurisdiction and is not approved for human or veterinary use. Peptsche supplies it as a lyophilized powder sealed in a single use glass vial for controlled laboratory investigation.
What is Retatrutide studied for in research?
Published laboratory work covers multiplexed receptor signalling assays run across parallel cell lines each expressing one target receptor, comparative pharmacology against single and dual receptor agonists, and analytical method development for acylated peptides. Because no pharmacopoeial monograph exists for this compound, method work relies on the batch Certificate of Analysis rather than an official standard. These describe areas of laboratory study rather than established outcomes outside those experimental systems.
How does Retatrutide work in laboratory research?
In the systems described in the literature the peptide activates the glucagon receptor, the glucose dependent insulinotropic polypeptide receptor and the glucagon like peptide 1 receptor, all three of which couple through stimulatory G protein to adenylate cyclase. Cyclic adenosine monophosphate accumulation therefore serves as the common readout across the three assays, and reported relative potency is unbalanced rather than equal. Alpha aminoisobutyric acid substitutions stabilise helical geometry against proteolytic cleavage and a twenty carbon diacid chain binds serum albumin reversibly.
How is the quality of Peptsche Retatrutide verified?
Every production lot of Peptsche Retatrutide is evaluated analytically, with identity confirmed using techniques such as mass spectrometry and purity quantified by high performance liquid chromatography against the stated specification of 99% or greater. Peptsche works with Janoshik Analytical, an independent testing laboratory, for third party verification, and a batch specific Certificate of Analysis accompanies each order.
How should unopened Retatrutide be stored?
Unopened vials should be stored sealed at 2 to 8 °C, protected from heat, light and moisture. Vials should reach ambient temperature before opening so condensation does not form on the cold powder. Lot number, receipt date and storage conditions should be recorded in laboratory documentation so results stay traceable to a batch.
Is Retatrutide intended for human use?
No. Retatrutide is supplied strictly for laboratory research use only. It is not approved for human consumption, veterinary use, diagnosis, treatment or any medical application.
Why do researchers choose Peptsche for Retatrutide?
Peptsche supplies Retatrutide at 99% or greater purity by HPLC, verified per batch, as a lyophilized powder sealed in a single use glass vial that stays stable through transport and cold storage. Because no pharmacopoeial monograph exists for this compound, batch specific analytical documentation and independent third party confirmatory analysis are what support reproducibility across research workflows.
Scientific References
- Coskun T, Urva S, Roell WC, Qu H, Loghin C, Moyers JS, O'Farrell LS, Briere DA, et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept. Cell Metabolism. 2022;34(9):1234 to 1247. https://pubmed.ncbi.nlm.nih.gov/35985340/
- Urva S, Coskun T, Loh MT, Du Y, Thomas MK, Gurbuz S, Haupt A, Benson CT, Hernandez-Illas M, D'Alessio DA, Milicevic Z. LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial. The Lancet. 2022;400(10366):1869 to 1881. https://pubmed.ncbi.nlm.nih.gov/36354040/
- Jastreboff AM, Kaplan LM, Frías JP, Wu Q, Du Y, Gurbuz S, Coskun T, Haupt A, Milicevic Z, Hartman ML. Triple-Hormone-Receptor Agonist Retatrutide for Obesity, A Phase 2 Trial. New England Journal of Medicine. 2023;389(6):514 to 526. https://pubmed.ncbi.nlm.nih.gov/37366315/
RESEARCH USE ONLY
These compounds are NOT intended for human consumption, clinical use, or veterinary applications. We are not affiliated with any pharmaceutical companies or their commercial medications. By placing an order, you certify these materials will be used exclusively for in vitro testing and laboratory experimentation only. Bodily introduction of any kind into humans or animals is strictly forbidden by law. This product should only be handled by licensed, qualified professionals. This product is not a drug, food, or cosmetic and may not be misbranded, misused or mislabeled as a drug, food or cosmetic.