Retatrutide vs Tirzepatide
Retatrutide and Tirzepatide are two of the most-researched next-generation metabolic peptides. The essential difference: Tirzepatide is a dual GLP-1 / GIP receptor agonist, while Retatrutide adds a third receptor — glucagon — making it a triple agonist.
This page compares the two side by side so researchers can quickly see receptor profile, available vial strengths, and how each fits into current research protocols.
Side-by-side
| Retatrutide | Tirzepatide | |
|---|---|---|
| Receptor profile | Triple: GLP-1 / GIP / Glucagon | Dual: GLP-1 / GIP |
| Class | Triple agonist | Dual agonist |
| Vial strengths | 20mg · 30mg · 40mg | 20mg · 40mg |
| Dosing cadence | Weekly (long-acting) | Weekly (long-acting) |
| Research maturity | Newer — frontier research | Extensive published literature |
| Purity (HPLC) | 99%+ | 99%+ |
Mechanism at a glance
GLP-1 receptor activity is common to both peptides and underpins most of the published metabolic research on this class.
GIP (glucose-dependent insulinotropic polypeptide) receptor activity is what makes Tirzepatide a "dual agonist" — it is the second lever Tirzepatide pulls on beyond GLP-1.
Glucagon receptor activity is the third lever unique to Retatrutide, and is the distinguishing feature of triple-agonist research peptides.
Reconstitution & handling
Both peptides are supplied as lyophilised powder and reconstituted with bacteriostatic water. Our free peptide calculator handles the maths for either compound. Store at 2–8°C after reconstitution and use within 28 days.
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View full shopFrequently asked questions
What's the core difference between Retatrutide and Tirzepatide?
Retatrutide is a triple receptor agonist — it targets GLP-1, GIP and glucagon receptors in a single molecule. Tirzepatide is a dual agonist, targeting only GLP-1 and GIP. The added glucagon receptor activity is the defining difference in research.
Which has been researched longer?
Tirzepatide has a longer and larger body of published research. Retatrutide is newer and sits at the frontier of triple-agonist metabolic research.
What vial strengths are available?
We stock Retatrutide in 20mg, 30mg and 40mg lyophilised vials. Tirzepatide is available in 20mg and 40mg vials. All are HPLC verified at 99%+ purity.
Are the half-lives similar?
Both are long-acting research peptides designed for weekly protocols. Reported half-lives fall in a broadly similar range, though exact values differ between published sources.
Which should I choose for research?
That depends entirely on the receptor profile your protocol requires. Tirzepatide for dual GLP-1/GIP work; Retatrutide when glucagon-receptor activity is part of the study design.
Disclaimer: All products sold by Peptides UK 4U are for laboratory and research purposes only. They are not intended for human or animal consumption, diagnosis, treatment or prevention of any disease.