What is retatrutide?
Retatrutide (development code LY3437943, also called Reta or Triple G) is an investigational single-molecule peptide studied for its ability to activate three metabolic receptors at once: the glucagon-like peptide-1 (GLP-1) receptor, the glucose-dependent insulinotropic polypeptide (GIP) receptor, and the glucagon receptor. Developed by Eli Lilly, it belongs to the incretin class of metabolic peptides and is one of the most-studied triple-hormone-receptor agonists to date. In this guide it is discussed strictly as a research compound. Retatrutide is not approved by the TGA or any regulator, and NovaPeptides supplies it for laboratory research use only, not for human consumption.
Every reference to retatrutide's effects below is drawn from published preclinical and clinical research. Nothing here is medical advice, dosing guidance, or a claim of safety or efficacy for human use. Retatrutide is supplied for research use only and is not for human consumption.
The triple-agonist mechanism explained
What sets retatrutide apart in the literature is the number of receptors it engages. Semaglutide is a single agonist (GLP-1 only). Tirzepatide is a dual agonist (GLP-1 plus GIP). Retatrutide is a triple agonist, adding glucagon-receptor activation on top of both incretin pathways. Each arm is investigated for a distinct contribution to metabolic signalling in research models.
The three receptor arms
- GLP-1 receptor: researched for its role in appetite signalling, satiety and glucose-dependent insulin secretion, the same pathway semaglutide targets.
- GIP receptor: the second incretin pathway added by tirzepatide, investigated for effects on energy balance and adipose-tissue signalling.
- Glucagon receptor: the third arm unique to retatrutide, studied for its potential influence on energy expenditure and hepatic fat metabolism, a mechanism dual agonists do not engage.
The research hypothesis behind combining all three is that glucagon-receptor agonism may raise energy expenditure while the GLP-1 and GIP arms reduce energy intake, a combination investigated for whether it produces larger metabolic effects than single or dual agonists in the studied models. This triple mechanism is why retatrutide is nicknamed Triple G in the research community.
The published research: NEJM phase 2 and the TRIUMPH program
Retatrutide is supported by peer-reviewed clinical research, which is relatively unusual for a compound at this stage of investigation. The two pillars are the phase-2 obesity trial and the ongoing phase-3 TRIUMPH program.
The phase-2 trial was published in the New England Journal of Medicine (NEJM) in 2023. It was a randomised, double-blind, placebo-controlled study in adults with obesity that evaluated escalating doses over a 48-week treatment period. According to the published trial, the highest 12 mg dose was associated with a mean body-weight reduction of up to approximately 24% at 48 weeks, with the effect reported as dose-dependent across the study arms. The most commonly reported adverse events were gastrointestinal and were described in the trial as generally mild to moderate and dose-related.
Building on that, Eli Lilly initiated the phase-3 TRIUMPH program, a multi-trial clinical program investigating retatrutide across a range of doses and endpoints, including obesity and related conditions. TRIUMPH represents the pivotal-stage research that any future regulatory submission would draw upon.
Retatrutide is reported in the literature as the first triple GLP-1 / GIP / glucagon receptor agonist to reach large-scale phase-3 clinical investigation, and the up-to-24% figure from its phase-2 trial is among the higher weight reductions reported for an investigational molecule in the incretin class.
Retatrutide vs tirzepatide vs semaglutide
The clearest way to place retatrutide is against the two better-known incretin peptides. The defining difference is the receptor count: one, two, or three. The table below summarises how the three compounds compare on mechanism and research stage. Any figures shown are the headline numbers attributed to each compound's own published research and are not comparative or efficacy claims.
| Attribute | Retatrutide | Tirzepatide | Semaglutide |
|---|---|---|---|
| Also known as | LY3437943, Reta, Triple G | LY3298176, Mounjaro, Zepbound | Ozempic, Wegovy |
| Receptors targeted | GLP-1 + GIP + glucagon | GLP-1 + GIP | GLP-1 only |
| Agonist type | Triple agonist | Dual agonist | Single agonist |
| Developer | Eli Lilly | Eli Lilly | Novo Nordisk |
| Glucagon arm | Yes (unique) | No | No |
| Research stage | Phase 3 (TRIUMPH), investigational | Approved in some markets | Approved in some markets |
| Headline research figure | Up to ~24% body-weight reduction reported at 48 weeks (phase-2 trial, 12 mg) | Reported in its own published trials | Reported in its own published trials |
| TGA status | Not approved | Varies by product | Varies by product |
In short: semaglutide pioneered single-receptor incretin research, tirzepatide added the GIP arm as a dual agonist, and retatrutide adds the glucagon arm as a triple agonist. Retatrutide is the only one of the three still fully investigational, with no regulatory approval anywhere.
TGA status and legal position in Australia
Retatrutide is not approved by the Therapeutic Goods Administration (TGA). It is an investigational compound that remains in phase-3 clinical trials, and no regulator worldwide has granted it marketing approval. There is no approved retatrutide product available for prescription or supply for human use in Australia.
What this means in practice
- Retatrutide cannot be lawfully supplied, advertised, or sold for human therapeutic use in Australia.
- NovaPeptides supplies retatrutide strictly as a research reference material for laboratory use only.
- It is not a medicine, not a supplement, and is not intended for human consumption or self-administration.
- The TGA has publicly cautioned about unapproved peptides that have not been evaluated for safety, quality or efficacy, which is exactly why the research-use-only framing matters.
Nothing on this page should be read as encouragement to use retatrutide in humans. It is provided so researchers can understand the compound, its mechanism, and the published literature. Retatrutide is for research use only and is not for human consumption.
How NovaPeptides supplies retatrutide
NovaPeptides supplies retatrutide as complete research kits rather than loose vials. Each kit is designated by strength: RT10, RT20, RT30 and RT60, corresponding to the total peptide content of the kit. Every kit ships with a reusable dosing pen so researchers can measure reconstituted material accurately in a laboratory setting.
What is in a retatrutide research kit
- The retatrutide reference compound at the labelled strength (RT10 / RT20 / RT30 / RT60).
- A reusable dosing pen for precise volumetric research measurement.
- A batch-specific Novagen Laboratories Certificate of Analysis (COA).
- A unique verification key printed with the batch.
Every batch carries a Novagen Laboratories COA documenting identity and purity for that specific lot. The COA has a unique key you can enter at novagenlaboratories.com to confirm the result is genuine and matches your kit. This third-party verification is what separates a documented research reference material from an unverified product.
NovaPeptides operates as a catalogue and education resource. There is no online cart or public pricing. To enquire about retatrutide research kits and COA verification, message the NovaPeptides team on WhatsApp.
Handling, reconstitution and storage notes
Retatrutide is supplied as a lyophilised (freeze-dried) peptide and is handled like other research peptides. These are general laboratory-handling notes, not dosing or usage instructions, and they do not imply any human application.
General laboratory handling
- Lyophilised retatrutide is typically stored cold and kept away from light and moisture until reconstitution.
- Reconstitution in a research setting is performed with bacteriostatic or sterile water, with the peptide and diluent brought together gently rather than agitated.
- Once reconstituted, peptide solutions are generally refrigerated and used within the timeframe appropriate to the study.
- Always confirm identity and purity against the batch COA before any research use.
For the underlying reconstitution arithmetic (concentration equals milligrams of powder divided by millilitres of diluent, and pen-click volumes), researchers should work from the specific kit strength and their own laboratory protocol. NovaPeptides provides the material and the verified COA; the research design is the researcher's responsibility.
Verified by Novagen Laboratories
Every NovaPeptides batch, including the Retatrutide in the RT60 research kit, ships with a verifiable Novagen Laboratories Certificate of Analysis covering identity, content and purity. Each certificate carries a unique key so you can confirm it is genuine yourself.
Verify any batch yourself
No smoke, no mirrors. Copy the unique key printed on the COA, enter it at Novagen Laboratories, and the certificate is confirmed as genuine. Ask us on WhatsApp and we will send the report for your current batch.
Verify at novagenlaboratories.com →How to research Retatrutide with NovaPeptides
At NovaPeptides, Retatrutide is supplied within the RT60 research kit as a complete, ready-to-assemble research kit rather than a loose vial, with the reusable dosing pen, bacteriostatic water, needle heads, an extraction syringe and a thermal hard case, plus a verifiable Novagen Laboratories Certificate of Analysis. Because the right concentration depends on how much bacteriostatic water you reconstitute with, we keep the click-by-click method on a U-100 pen in one place.
RT60 research kit
Contains Retatrutide, supplied as a complete, ready-to-assemble research kit. Research use only.
Enquire about RetatrutideNew to reconstitution? Our interactive pen and dosing guide shows how clicks convert to milligrams on a U-100 pen, with a switch for 2mL or 3mL of bacteriostatic water. It is provided for research reference only and is not a recommendation for human use. The dose you target is a decision for a qualified professional, not advice from us.
Frequently asked questions
What is retatrutide?+
Retatrutide (LY3437943, also called Reta or Triple G) is an investigational single-molecule peptide studied for its activity at three receptors: GLP-1, GIP and glucagon. Developed by Eli Lilly, it is one of the most-studied triple-hormone-receptor agonists and is currently in phase-3 clinical trials. It is not approved by any regulator and is supplied by NovaPeptides for laboratory research use only, not for human consumption.
How does retatrutide differ from tirzepatide and semaglutide?+
The difference is the number of receptors engaged. Semaglutide is a single agonist targeting GLP-1 only. Tirzepatide is a dual agonist targeting GLP-1 and GIP. Retatrutide is a triple agonist studied for adding the glucagon receptor on top of both incretin pathways. That glucagon arm is investigated for effects on energy expenditure that dual and single agonists do not engage.
Why is retatrutide called Triple G?+
The nickname Triple G refers to its triple GPCR agonism, meaning it is studied for activating three G-protein-coupled receptors at once: GLP-1, GIP and glucagon. Researchers coined the shorthand because retatrutide is a leading example of a triple-receptor agonist, distinguishing it from dual agonists like tirzepatide and single agonists like semaglutide. It is also referred to by its development code LY3437943 and as Reta.
What did the retatrutide phase-2 trial show?+
The phase-2 trial, published in the New England Journal of Medicine in 2023, was a randomised placebo-controlled study in adults with obesity over 48 weeks. According to the published trial, the highest 12 mg dose was associated with a mean body-weight reduction of up to approximately 24% at 48 weeks, reported as dose-dependent. The most common adverse events were gastrointestinal and described in the trial as generally mild to moderate. This is reported research data, not a claim of efficacy for human use.
What is the TRIUMPH program?+
TRIUMPH is Eli Lilly's phase-3 clinical program for retatrutide, initiated after the phase-2 results. It is a multi-trial program investigating retatrutide across a range of doses and multiple metabolic endpoints. It represents the pivotal-stage research that any future regulatory submission would draw upon.
Is retatrutide approved in Australia?+
No. Retatrutide is not approved by the TGA or any other regulator worldwide. It remains an investigational compound in phase-3 clinical trials. There is no approved retatrutide product for human therapeutic use in Australia. NovaPeptides supplies it strictly as a research reference material for laboratory research use only, not for human consumption.
Is retatrutide legal in Australia?+
Retatrutide cannot be lawfully supplied, advertised or sold for human therapeutic use in Australia because it is unapproved by the TGA. It can, however, be supplied as a research-use-only reference material for legitimate laboratory work. It is not a medicine or supplement and must never be used for human consumption or self-administration. The TGA has publicly cautioned about unapproved peptides.
What is the difference between RT10, RT20, RT30 and RT60?+
RT10, RT20, RT30 and RT60 are NovaPeptides kit designations indicating the total retatrutide content of the research kit, with RT60 being the highest strength. Each kit ships as a complete unit with a reusable dosing pen and a batch-specific Novagen Laboratories Certificate of Analysis. Researchers select the strength that suits their study; NovaPeptides supplies the verified material only.
How do I verify a NovaPeptides retatrutide COA?+
Every retatrutide batch ships with a Novagen Laboratories Certificate of Analysis carrying a unique verification key. Enter that key at novagenlaboratories.com to confirm the COA is genuine and matches your kit. This third-party verification documents identity and purity for the specific lot, which is what separates a properly documented research reference material from an unverified product.
How is retatrutide supplied and how do I enquire?+
NovaPeptides supplies retatrutide as complete RT10, RT20, RT30 or RT60 research kits, each with a reusable dosing pen and a verifiable Novagen Laboratories COA. NovaPeptides is a catalogue and education resource with no online cart or public pricing. To enquire about retatrutide research kits, message the NovaPeptides team directly on WhatsApp. All material is supplied for research use only, not for human consumption.
What peptides are studied alongside retatrutide?+
Retatrutide is most often compared with tirzepatide, its closest mechanistic neighbour as a dual GLP-1 / GIP agonist, making it the natural reference for triple-versus-dual research. In separate recovery-focused research contexts, peptides such as BPC-157 and the GLOW blend (GHK-Cu, BPC-157 and TB-500) are also studied. Each is a distinct compound with its own published literature and is supplied for research use only.
Researching Retatrutide?
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