Home · Research Catalog · Retatrutide

Metabolic Research · Triple Agonist

Retatrutide: Research Overview

What is Retatrutide? Retatrutide is an investigational synthetic peptide that acts as a triple agonist ("triagonist") of the GIP, GLP-1, and glucagon receptors. Built on an approximately 39-amino-acid backbone with a fatty-acid modification, it was developed by Eli Lilly under the code LY3437943 and is studied in multi-receptor incretin pharmacology. It is sold strictly for laboratory research use.
VP Peptides Retatrutide research vial with box
Actual VP Peptides product · Research use only
Human data available ≥99% HPLC purity COA with every batch 3rd-party tested Research use only
Investigational — not approved

Retatrutide (LY3437943) is an investigational triple GIP/GLP-1/glucagon receptor agonist in Phase 3 trials. Human data are growing but it is not approved for any use and cannot be legally compounded. Present it as investigational research material, never as an approved product.

Technical profile

CompoundRetatrutide (LY3437943)
ClassSynthetic peptide, triple agonist of the GIP, GLP-1, and glucagon receptors
Structure~39-amino-acid backbone with a fatty-acid (lipidation) modification
Molecular weight~4731.3 g/mol (approximate)
CategoryMetabolic research / incretin pharmacology
Development statusInvestigational compound in clinical development (phase 3 trials by Eli Lilly); not an approved drug in any jurisdiction
Form suppliedLyophilized powder, sealed vial
StorageLyophilized: 2–8 °C, protected from light.
VerificationHPLC purity ≥99%, sterility, endotoxins, heavy metals — documented on the batch COA

Evidence at a glance

Research evidence is not one category. Human, animal (preclinical) and in-vitro / mechanistic data differ in strength — often sharply. VP Peptides separates them so no single line overstates the whole picture. Ratings are deliberately conservative and describe the published evidence base, not any effect in humans.

Human clinical
Limited
Animal / preclinical
Established
In-vitro / mechanistic
Strong
Regulatory statusRetatrutide (LY3437943) is an investigational triple GIP/GLP-1/glucagon receptor agonist not approved by the FDA for any indication (Phase 3 TRIUMPH program ongoing). As an investigational new drug it cannot be legally compounded; research material is not an approved pharmaceutical product.
What remains unknown
  • Human efficacy or safety of the research material as sold (not the clinical-trial or any approved product)
  • Long-term human safety and outcomes for any use
  • Identity, purity and stability of research-grade material versus the characterized investigational compound

What does the research literature cover?

Retatrutide is distinctive in the incretin research field because it engages three receptors — GIP, GLP-1, and glucagon — rather than one or two. Published research and laboratory investigation contexts include:

Important context: Retatrutide is an investigational compound in ongoing clinical development by Eli Lilly. It is not an approved drug anywhere, and summaries here describe areas of laboratory investigation — they are not claims about effects, safety, or efficacy in humans.

Why purity matters for Retatrutide research

A long, chemically modified peptide such as Retatrutide is demanding to synthesize: truncated sequences, deletion impurities, incomplete lipidation, or endotoxin contamination can all confound receptor-pharmacology experiments. Every VP Peptides Retatrutide batch ships with a Certificate of Analysis documenting ≥99% HPLC purity plus sterility, endotoxin and heavy-metal testing from independent third-party testing.

Request catalog access

Frequently asked questions

Is Retatrutide an approved drug?

No. Retatrutide is an investigational compound in clinical development (phase 3 trials conducted by Eli Lilly) and is not approved by the FDA or any other regulatory agency anywhere. Research-grade Retatrutide is supplied strictly for laboratory investigation — it is not a drug, supplement, or food ingredient, and it is not for human or veterinary use.

What does a Retatrutide Certificate of Analysis include?

Each batch COA documents HPLC purity (≥99% specification), sterility, endotoxin and heavy-metal screening results, along with batch number and test date.

How should Retatrutide be stored in the lab?

Lyophilized vials should be kept at 2–8 °C and protected from light.

How does Retatrutide differ from tirzepatide and semaglutide?

The three compounds differ in receptor coverage. Semaglutide is studied as a single (GLP-1 receptor) agonist, tirzepatide as a dual GIP/GLP-1 receptor agonist, and Retatrutide as a triple agonist that additionally engages the glucagon receptor. This makes the set a common comparison framework in incretin-pharmacology research.

Triple GIP/GLP-1/glucagon agonism, in context

What sets retatrutide apart in the incretin literature is that it engages three receptors at once. Most incretin-class molecules studied to date act on a single receptor (the GLP-1 receptor) or two (GIP and GLP-1); retatrutide adds a third arm — agonism at the glucagon receptor. The research question under study is what that third arm contributes. In the published work, GLP-1 and GIP signaling is discussed in relation to appetite and glucose-handling pathways, while glucagon-receptor signaling is investigated for its relationship to hepatic metabolism and energy expenditure. Combining all three in one molecule is what the literature characterizes as "triagonism," and the mechanistic question is whether adding glucagon-receptor engagement to the incretin axis alters metabolic signaling in ways single or dual agonists do not.

This mechanism is examined in investigational clinical research, not in approved therapy. A Phase 2 randomized trial reported dose-dependent metabolic changes among study participants (Jastreboff et al., N Engl J Med 2023), and a separate Phase 2a study examined the molecule in a metabolic liver-disease model (Sanyal et al., Nat Med 2024). It has since advanced into the Phase 3 TRIUMPH program, a set of registrational trials in adiposity-related conditions (ClinicalTrials.gov — NCT05929066 (2023)). These are investigational studies designed to test hypotheses about the molecule; they are not evidence of a marketable benefit.

This bears repeating plainly: retatrutide is an investigational compound. It is not approved by the FDA or any other regulator for any use, it cannot be legally compounded, and none of the trial findings above describe an effect of research-grade material as sold. The literature summarized here concerns the molecule and its mechanism as characterized in the scientific record — it is not a claim about safety, efficacy, or any outcome for VP Peptides' research material.

Selected research references

Related research compounds

Research use only. All products described on this page are furnished for laboratory research purposes only and are not for human or veterinary use, not for use in food or cosmetics, and not for any diagnostic or therapeutic application. Nothing on this page is medical advice or a claim of safety or efficacy in humans. Research summaries reference publicly available preclinical literature; specific citations are listed in the references above.