Rétatrutide (« reta ») ou tirzépatide : un seul récepteur de différence
Recherche sur la perte de poids et le métabolisme
Retatrutide and tirzepatide are the two most requested research peptides in Canada right now, and the difference between them is one receptor. Tirzepatide is a dual agonist — GIP and GLP-1. Retatrutide, commonly shortened to “reta”, engages those same two receptors plus a third: the glucagon receptor. Everything else people debate about the pair follows from that.
The receptor arithmetic
- Tirzepatide — GIP + GLP-1. A dual incretin-receptor agonist, and the more extensively characterised of the two in the published literature.
- Retatrutide — GIP + GLP-1 + glucagon. The triple agonist, and the newer molecule.
Both are synthetic peptides built on the incretin signalling system that regulates glucose handling and energy balance. The glucagon receptor is what separates them: engaging it alongside the other two produces a combined signalling profile in metabolic research models that dual agonists do not, which is precisely why retatrutide is the one generating the current wave of research interest.
Neither compound is “stronger” in any meaningful research sense — they are different tools. A study designed around dual agonism needs tirzepatide; a study examining triple-receptor signalling needs retatrutide. The research question picks the molecule.
Maturity of the literature
Tirzepatide has years of published characterisation behind it and is the better-mapped compound. Retatrutide’s literature is younger and still expanding, which is exactly what makes it an active research target — the open questions have not been closed yet.
Practical differences at the bench
As supplied materials the two are similar: lyophilised powder in sealed vials, reconstituted in a research setting with eau bactériostatique, kept cold and out of light. Vistara Labs supplies tirzepatide in 10 mg vials at 99.6% purity and retatrutide (reta) in 10 mg and 20 mg vials, both third-party tested with certificates of analysis available on request.
On the names
Retatrutide circulates under several labels — “reta” most commonly, and sometimes the invented family name “GLP-3”, which is not a real hormone. Tirzepatide is occasionally shortened to “tirz”. Whatever the label on a listing, the certificate of analysis is what confirms the molecule in the vial; a supplier who cannot produce one has nothing to substantiate the name.
Frequently asked questions
Is retatrutide the same as tirzepatide?
No. They are different molecules. Tirzepatide acts at two receptors (GIP and GLP-1); retatrutide acts at three (GIP, GLP-1 and glucagon).
Where can I buy reta or tirzepatide in Canada?
Vistara Labs supplies both as research materials, shipped from within Canada with no customs step. Payment is by Interac e-Transfer and COAs are available on request. Both are for laboratory research use only.
Which one should a researcher choose?
The one that matches the research question: dual-agonist work calls for tirzepatide, triple-agonist work calls for retatrutide. For comparative receptor studies, laboratories order both.
Sourcing note: researchers looking to buy tirzepatide in Canada can read our Tirzepatide buying guide for domestic-stock, purity and shipping details.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
References
Retatrutide has been evaluated in randomised, placebo-controlled human trials through phase 3.
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 TrialRandomised, double-blind, placebo-controlled phase 2 obesity trial, 48 weeks.
- Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USARandomised, double-blind, placebo- and active-controlled phase 2 trial; 281 participants with type 2 diabetes.
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trialRandomised phase 2a substudy; 98 participants with metabolic dysfunction-associated steatotic liver disease.
- Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trialDouble-blind randomised phase 3 trial in type 2 diabetes (TRANSCEND-T2D-1).
Links open the study record on PubMed so the source can be checked directly. Listing a study is not a claim that its findings apply to any other use, product or route of administration. Research use only.
