Ask anyone following metabolic research to name three peptides and you will almost certainly hear these: semaglutide, tirzepatide, retatrutide. They get lumped together constantly, and it is easy to see why. All three are synthetic incretin-class peptides, all three dominate the current literature, and all three appear in research catalogs like ours. Mechanically, though, they are not interchangeable, and the differences are exactly what makes each one worth studying on its own terms.
One receptor, two, or three
The cleanest way to keep them straight is to count receptor targets.
- Semaglutide is described in the literature as a GLP-1 receptor agonist. One target: the glucagon-like peptide-1 receptor, a central node in incretin signaling.
- Tirzepatide is a dual agonist. The published work characterizes it as acting on both the GIP receptor and the GLP-1 receptor.
- Retatrutide goes one further. It is described as a triple agonist engaging the GIP, GLP-1, and glucagon receptors at once.
That progression, from one receptor to two to three, is the storyline of the last decade of incretin research. Each added receptor changes the signaling profile, which is why laboratories study the three compounds side by side rather than treating them as substitutes.
Where each stands
Semaglutide and tirzepatide both exist as approved pharmaceutical products in their branded, clinically manufactured forms. Retatrutide is different: as of this writing it is an investigational compound moving through late-stage clinical trials, with results published in the peer-reviewed literature.
One distinction matters more than any other here. Research-grade peptide material, the kind we sell, is not a pharmaceutical product. It is not manufactured, tested, or regulated as a drug, and it is sold strictly for laboratory and in-vitro research. The shared molecule name does not make the two categories equivalent, and we label every vial accordingly.
What researchers actually study
In laboratory settings, work on these three peptides tends to center on receptor pharmacology: binding behavior, signaling cascades downstream of GIP, GLP-1, and glucagon receptor activation, and comparative effects in cell-based and animal models of metabolism. The compounds are also common reference materials in analytical chemistry, where labs verify identity and purity of incretin-class peptides by chromatography and mass spectrometry.
The three in our catalog
We stock all three as lyophilized research compounds: Semaglutide (10mg), Tirzepatide (20mg), and Retatrutide (10mg). Each product page lists the CAS number, molecular formula, and molecular weight, and every vial carries a printed lot number you can match against our public COA ledger. Lots still in third-party testing are labeled pending. We do not publish results we do not have.
Quick answers
Are these three peptides interchangeable in research? No. They differ in receptor targets and signaling profiles, which is precisely why comparative studies exist.
Is research-grade semaglutide the same as the branded drug? No. Research-grade material is not a pharmaceutical product and is a laboratory material only.
How do I verify what is in the vial? Match the lot number on the label to its entry in the COA ledger, where third-party certificates are published as testing completes.
For laboratory and in-vitro research use only.
For laboratory and in-vitro research use only. Not for human or veterinary use. See our research-use disclaimer.
