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Where this sits in the RT3 Comparisons cluster.

Knowledge journey

  1. collectionRT3
  2. guideComparisons
  3. comparisonRT3 vs Tirz
  4. comparisonRT3 vs Sema
  5. comparisonSema vs Tirz
  6. collectionGLP-1 Research Hub
  7. guideWhat is RT3?
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Comparison guide · Product Comparisons

RT3 vs Sema.

A laboratory-focused comparison of RT3 (LY3437943) and Sema — triple receptor agonist versus single GLP-1 receptor agonist. Receptor profile, mechanism, class and analytical release 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 that acts on the GLP-1, GIP and glucagon receptors simultaneously. Sema is a single GLP-1 receptor agonist. Both are supplied as lyophilised research peptides at ≥99% HPLC purity — RT3 is used as the triple-incretin reference and Sema as the single-receptor GLP-1 reference in comparative research.
Key facts

At a glance.

  • RT3: triple agonist (GLP-1 · GIP · glucagon)
  • Sema: single agonist (GLP-1)
  • Both: lyophilised powder, ≥99% HPLC purity
  • Both: batch-specific COA with every order
  • Both: laboratory research use only
Side by side

The compounds.

RT3 research peptide vial

RT3

Triple receptor agonist targeting GLP-1, GIP and glucagon — the newest generation of incretin research peptides.

Shop RT3 →
Sema research peptide vial

Sema

The established single GLP-1 receptor agonist reference peptide, used across metabolic and glycaemic research models.

Shop Sema →
Comparison table

Specifications.

FeatureRT3Sema
Receptor profileGLP-1 · GIP · GlucagonGLP-1 only
Compound classTriple agonist peptideSingle-receptor GLP-1 agonist
Primary research interestTriple-hormone synergism, energy expenditure, body compositionGLP-1 pathway biology and glycaemic research
Analytical release≥99% HPLC-UV, mass spec, endotoxin≥99% HPLC-UV, mass spec, endotoxin
FormLyophilised powderLyophilised powder
Storage2–8°C dark; ~30 days reconstituted2–8°C dark; ~30 days reconstituted
Research maturityEmerging triple-incretin referenceEstablished single-GLP-1 reference
Research context

Why compare them.

Sema is the anchor GLP-1 reference in modern peptide research — a well-characterised single-receptor agonist against which every newer incretin candidate is measured. RT3 sits at the opposite end of the class spectrum: three receptor targets in a single molecule, adding GIP and glucagon activity to the GLP-1 axis.

For laboratory groups isolating the contribution of GLP-1 alone versus combined incretin signalling, the two compounds are the natural comparators. The paired middle-ground compound — Tirz (dual GLP-1 / GIP) — is covered in our companion RT3 vs Tirz guide.

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 acting on GLP-1, GIP and glucagon receptors.
Sema
Single GLP-1 receptor agonist and the most widely referenced GLP-1 research peptide.
GLP-1
Glucagon-like peptide-1: an incretin hormone regulating insulin release and appetite.
Triple / single agonist
Peptides engineered to activate three vs one receptor respectively.
Frequently asked questions

FAQs.

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

RT3 activates three receptors (GLP-1, GIP and glucagon). Sema activates one (GLP-1). RT3 is used where research questions require combined incretin activity; Sema is the isolated GLP-1 reference.

Are both compounds long-acting?[+]

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

Can I use both in the same experiment?[+]

Comparative research designs frequently include both to attribute observed effects to GLP-1 alone versus combined GLP-1 / GIP / glucagon activity. Sourcing both from matched release specifications supports that comparison.

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 offered by BuyRetaUK for human or veterinary administration.

References

Scientific sources & further reading.

  1. [1]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 →
  2. [2]Coskun T. et al. (2022) LY3437943, a novel triple GIP, GLP-1 and glucagon receptor agonist. Cell Metabolism, 34(9) DOI: 10.1016/j.cmet.2022.07.013DOI →
  3. [3]Lau J. et al. (2015) Discovery of the once-weekly glucagon-like peptide-1 (GLP-1) analogue Sema. Journal of Medicinal Chemistry, 58(18) DOI: 10.1021/acs.jmedchem.5b00726DOI →

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.

View profile →
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
Comparisons
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Batch verification

Every batch of RT3, Sema 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 Tirz

Side-by-side comparison of RT3 and Tirz across receptor profile, research context and analytical considerations.

5 min read — Read guide →