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Where this sits in the RT3 Comparisons cluster.

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Comparison guide · Product Comparisons

RT3 vs Tirz.

A side-by-side laboratory comparison of RT3 (LY3437943) and Tirz — receptor profile, mechanism, class, analytical release specification and research context, for UK researchers.

Published
June 2026
Last reviewed
June 2026
Next review
December 2026
Version
v1.1
Reading time
7 min read
Reviewed by
BuyRetaUK Scientific Review Team
Editorial team
BuyRetaUK Editorial Team
Review status
Scientific review complete
Quick answer

In short.

RT3 is a triple receptor agonist (GLP-1 / GIP / glucagon). Tirz is a dual receptor agonist (GLP-1 / GIP). Both are supplied as lyophilised research peptides at ≥99% HPLC purity and are used together in research models that compare triple- versus dual-incretin activity.
Key facts

At a glance.

  • RT3: triple agonist (GLP-1 · GIP · glucagon)
  • Tirz: dual agonist (GLP-1 · GIP)
  • Both compounds: lyophilised powder, ≥99% HPLC purity
  • Both compounds: independent third-party COA per batch
  • Both compounds: laboratory research use only
Side by side

The compounds.

RT3 research peptide vial

RT3

Triple agonist peptide targeting GLP-1, GIP and glucagon receptors — of interest in metabolic, body-composition and energy-balance research.

Shop RT3 →
Tirz research peptide vial

Tirz

Dual agonist peptide targeting GLP-1 and GIP receptors — a well-characterised reference compound in incretin research.

Shop Tirz →
Comparison table

Specifications.

FeatureRT3Tirz
Receptor profileGLP-1 · GIP · Glucagon (triple)GLP-1 · GIP (dual)
Compound classTriple agonist peptideDual agonist peptide
Primary research interestTriple-hormone synergism, energy expenditure, body compositionDual-incretin biology, glycaemic and metabolic research
Analytical release≥99% HPLC-UV, mass spec identity, endotoxin≥99% HPLC-UV, mass spec identity, endotoxin
FormLyophilised powderLyophilised powder
Storage2–8°C dark; ~30 days reconstituted2–8°C dark; ~30 days reconstituted
Research maturityEmerging triple-incretin referenceWell-characterised dual-incretin reference
Research context

Why compare them.

RT3 and Tirz are frequently referenced side by side because they represent adjacent generations of incretin research chemistry. Tirz established the dual GLP-1 / GIP receptor model in the laboratory literature. RT3 extends that model with a third receptor arm — glucagon — that alters the profile of energy expenditure and hepatic activity captured in research models.

Laboratory groups building comparative datasets typically procure both compounds as lyophilised powders at matched release specifications so that receptor-level contributions can be isolated. Our companion guide RT3 vs Sema completes the triangle by comparing the triple agonist against the single GLP-1 reference.

All observations here are laboratory research context. BuyRetaUK does not make clinical, therapeutic or off-label claims.

Definitions

Key terms.

RT3 (LY3437943)
Triple receptor agonist peptide acting on GLP-1, GIP and glucagon receptors.
Tirz
Dual incretin receptor agonist acting on GLP-1 and GIP receptors.
Triple / dual agonist
Peptides engineered to bind three or two incretin-related receptors simultaneously.
Incretin
Gut-derived hormone family (chiefly GLP-1 and GIP) that regulates insulin release.
Frequently asked questions

FAQs.

What is the core difference between RT3 and Tirz?[+]

RT3 is a triple receptor agonist (GLP-1 / GIP / glucagon). Tirz is a dual receptor agonist (GLP-1 / GIP). The glucagon arm is the distinguishing feature of the triple class.

Are both compounds long-acting?[+]

Yes. Both are engineered as long-acting peptides suitable for weekly-dosing research protocols in the studies that reference them.

Which compound is better established in research?[+]

Tirz is the more established dual-incretin reference; RT3 is the more recently characterised triple-incretin candidate. Many laboratories reference both together.

Do BuyRetaUK batches ship with COAs?[+]

Yes — every batch of both compounds ships with a batch-specific Certificate of Analysis reporting HPLC purity, mass-spec identity and endotoxin data.

Are these compounds approved for human use?[+]

No. BuyRetaUK supplies both strictly for in-vitro laboratory research. Neither is approved by BuyRetaUK for human or veterinary administration.

References

Scientific sources & further reading.

  1. [1]Coskun T. et al. (2022) LY3437943, a novel triple GIP, GLP-1 and glucagon receptor agonist for weight loss and glycemic control. Cell Metabolism, 34(9) DOI: 10.1016/j.cmet.2022.07.013DOI →
  2. [2]Jastreboff A.M. et al. (2023) Triple-hormone-receptor agonist RT3 for obesity — a phase 2 trial. New England Journal of Medicine, 389(6) DOI: 10.1056/NEJMoa2301972DOI →
  3. [3]Coskun T. et al. (2018) LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes. Molecular Metabolism, 18 DOI: 10.1016/j.molmet.2018.09.009DOI →

Peer-reviewed citations are added as each article is expanded. See our editorial standards for our sourcing and accuracy commitments.

Editorial team
BuyRetaUK Editorial Team
Author · BuyRetaUK

The BuyRetaUK editorial team publishes laboratory-focused reference content on research peptides, analytical methods and Certificates of Analysis. All articles are written for in-vitro research contexts only.

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Scientific reviewer
BuyRetaUK Scientific Review Team
Scientific reviewer

Every editorial article is reviewed against our accuracy commitment and quality-assurance checklist before publication. Named reviewer profiles are added as our reviewer network expands.

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Editorial standards

How this content is produced.

Every article follows a documented editorial process — sourcing, scientific review, update cadence and correction policy — so researchers can rely on what we publish.

Read the full editorial standards →
Recommended reading path

How to research this topic.

Recommended reading path

  1. Step 01
    Start here — What is RT3?

    Baseline understanding of the triple agonist.

  2. Step 02
    Compare with Tirz

    Triple vs dual receptor profile.

  3. Step 03
    Compare with Sema

    Triple vs single GLP-1 profile.

  4. Step 04
    Understand COAs

    Verify identity and purity of any compound.

  5. Step 05
    Browse compounds

    All GLP-1 / GIP / glucagon research peptides.

Topic overview

RT3 Comparisons at a glance.

Topic overview

Knowledge Hub
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Batch verification

Every batch of RT3, Tirz ships with a third-party HPLC and mass-spec Certificate of Analysis. Browse the live COA library to verify your lot.

Research tools
FAQ
Which is the newer research compound?

RT3 is the more recently characterised compound in the academic literature, while Tirz is the more established reference.

Read: RT3 vs Tirz
Are both compounds GLP-1 agonists?

Yes — both act on the GLP-1 receptor, but RT3 also acts on GIP and glucagon receptors.

Read: RT3 vs Sema
Is RT3 approved for human use?

No. RT3 is supplied strictly for laboratory research and is not approved for human or veterinary administration.

Read: What is RT3?
What receptors does RT3 act on?

In published research it has been characterised as a triple agonist acting on the GLP-1, GIP and glucagon receptors.

Read: What is RT3?
Continue reading

Suggested next reading.

Product Comparisons
RT3 vs Sema

How RT3 and Sema differ in receptor activity, compound class and laboratory research framing.

5 min read — Read guide →