“GLP-1” is one of the most-asked topics in peptide research. This is a research-framed explainer of what these peptides are and how the popular ones differ. It makes no medical, weight-loss, or dosing claims.
What “GLP-1” means
GLP-1 stands for glucagon-like peptide-1, an incretin involved in glucose-related signalling. Peptides described as GLP-1 receptor agonists are molecules studied for how they interact with that receptor in metabolic research.
How the popular ones differ
| Peptide | Receptor targets studied |
|---|---|
| Semaglutide | GLP-1 (single agonist) |
| Tirzepatide | GLP-1 + GIP (dual agonist) |
| Retatrutide | GLP-1 + GIP + glucagon (triple agonist) |
Other compounds in this research area include cagrilintide (an amylin-analogue studied alongside GLP-1 agonists) and newer agents such as mazdutide and survodutide.
How they’re supplied and verified
- Form: lyophilized research peptides in sealed vials.
- Verification: batch-matched third-party COA with HPLC purity and MS identity.
- Use: in-vitro/laboratory research only — not therapeutics.
FAQ
What’s the difference between semaglutide and tirzepatide? In research terms, semaglutide is a single GLP-1 receptor agonist, while tirzepatide is a dual GLP-1/GIP agonist. Retatrutide adds a third target (glucagon).
Are these weight-loss drugs? They are sold here as research reagents, not medicines, and we make no medical or weight-loss claims. Their study belongs to metabolic research.
What is cagrilintide? An amylin-analogue peptide studied alongside GLP-1 receptor agonists in metabolic research.
Browse verified research peptides
Every batch we ship is independently tested by Janoshik Analytical (HPLC for purity, mass spectrometry for identity) with a batch-matched Certificate of Analysis you can verify. Browse the catalog → · See the latest COAs →
*For laboratory and research use only. Not for human or veterinary use, consumption, or administration. Nothing in this article is medical advice or a claim that any compound treats, cures, or prevents any condition. This is general information, not legal advice.*
This page is a research-context explainer of GLP-1 and the multi-agonist peptides studied alongside it, covering what glucagon-like peptide-1 signalling is and how semaglutide, tirzepatide and retatrutide differ in the receptors they act on. It also covers the vocabulary used in this literature, what a batch-matched certificate of analysis reports, and how lyophilized research vials are handled and documented. Everything here is framed for laboratory research use only — no medical, dosing or weight-loss claims are made or implied.
Why the incretin axis has more than one target
GLP-1 is one of two incretin hormones commonly discussed together. The other is glucose-dependent insulinotropic polypeptide (GIP), which acts through its own receptor. Glucagon, produced in pancreatic alpha cells, signals through a third receptor in the same broad family. All three are class B G protein-coupled receptors, which is why a single peptide sequence can be engineered to engage more than one of them.
That structural relationship is the reason the research literature moved from single agonists to dual and triple agonists. Each additional receptor adds a different signalling pathway to the experiment, so a dual or triple agonist is not simply a stronger version of a single agonist — it is a different set of variables to isolate and measure.
For a researcher, this matters when designing controls. Comparing a triple agonist against a single agonist without an intermediate dual-agonist arm makes it difficult to attribute any observed difference to a specific receptor.
Reading the names: agonist, analogue and the -tide suffix
The nomenclature in this area is consistent enough to be useful. The shared -tide ending marks a peptide-based compound, and the stems carry information about the class: the -glutide family relates to glucagon-family receptor activity, while cagrilintide belongs to the amylin-analogue group rather than the incretin group.
The distinction between an agonist and an analogue is worth keeping straight in written work. An agonist is defined by what it does at a receptor. An analogue is defined by what it resembles structurally. A compound can be both, and papers often use the terms interchangeably even though they describe different things.
What a batch-matched COA actually tells you
A certificate of analysis is only useful if it corresponds to the vial in your hand. Batch-matched means the lot number printed on the vial appears on the document, so the analysis describes that specific synthesis run rather than a representative sample from an earlier batch.
Two analyses do different jobs on that document. High-performance liquid chromatography separates the sample and reports purity as the proportion of the main peak relative to related substances — truncated sequences, deletion products and other synthesis by-products. Mass spectrometry confirms identity by matching the observed molecular mass to the expected mass of the target sequence.
Purity and identity are not substitutes for one another. A compound can be highly pure and still be the wrong molecule, or correctly identified and insufficiently pure for a sensitive assay. Reviewers and internal QA processes generally expect both.
- Lot or batch number matching the vial label
- HPLC chromatogram with a stated purity percentage
- MS identity confirmation against the expected mass
- Appearance and physical description of the lyophilized material
- Date of analysis and the method used
Handling lyophilized vials in a research setting
These compounds are supplied as lyophilized (freeze-dried) powder in sealed vials because peptides are considerably more stable dry than in solution. The freeze-drying step removes water, which slows the hydrolysis and aggregation pathways that degrade peptides over time.
Standard laboratory practice applies once a vial is opened. Keep material cold and protected from light, allow sealed vials to reach room temperature before opening to limit condensation, and aliquot reconstituted solutions rather than subjecting a single stock to repeated freeze-thaw cycles. Record the date of reconstitution alongside the lot number so results can be traced back to a specific vial and handling history.
Follow your institution’s own SOPs and your risk assessment for the compound class. Nothing on this page is a protocol.
Research-use-only framing for Canadian buyers
Compounds in this category are supplied as research reagents for in-vitro and laboratory work. They are not therapeutics, not approved medicines, and not intended for human or veterinary administration. Their appearance in metabolic research literature does not change that status.
Practically, this means purchasing sits with qualified research buyers — university groups, biotech companies, contract labs and institutional purchasers — who can document intended research use. Keeping the COA on file with your order paperwork covers the traceability side of that documentation, and shipping within Canada avoids the customs delays that can subject temperature-sensitive material to unnecessary transit time.
| Term | What it describes | Basis of the definition |
|---|---|---|
| Receptor agonist | A molecule that binds a receptor and activates its signalling | Functional — defined by activity |
| Analogue | A molecule structurally similar to a reference peptide | Structural — defined by sequence or shape |
| Dual / triple agonist | Activity at two or three distinct receptors | Functional — defined by receptor coverage |
| Incretin | A gut hormone class involved in glucose-related signalling (GLP-1, GIP) | Physiological classification |
| Amylin analogue | A compound resembling amylin rather than an incretin | Structural, different hormone family |
Common questions
Why are dual and triple agonists studied at all if a single agonist already targets GLP-1?
Because GLP-1, GIP and glucagon receptors belong to the same receptor family but drive different signalling pathways. Adding a second or third target gives researchers a way to compare pathway contributions within one experimental series rather than across unrelated compounds. It is a question of experimental design, not potency.
What is the difference between HPLC purity and MS identity on a COA?
HPLC purity reports how much of the sample is the main peak versus related impurities from synthesis. Mass spectrometry confirms that the main peak is the intended molecule by matching its measured mass to the expected value. Purity answers “how clean,” identity answers “is it the right compound.”
Why is a batch-matched COA important rather than any COA for the same product?
Each synthesis run produces slightly different impurity profiles. A COA from a different lot describes a different batch of material, so it cannot support traceability if you need to explain an anomalous result or satisfy an internal audit. Matching the lot number on the vial to the document is what makes the analysis meaningful.
How should lyophilized research peptide vials be stored?
Keep sealed vials cold, dry and away from light, and follow the storage conditions on the product documentation and your own SOPs. Bring vials to room temperature before opening to reduce condensation, and aliquot any reconstituted material so a single stock is not repeatedly frozen and thawed.
What are mazdutide and survodutide?
They are newer peptides that appear in the same multi-agonist research area as tirzepatide and retatrutide, studied for their activity across incretin and glucagon-family receptors. As with everything on this page, they are discussed here as research compounds only.
Can anyone in Canada order these compounds?
They are supplied to qualified research buyers — laboratories, universities, biotech companies and researchers purchasing for documented laboratory use. They are not sold for human or veterinary use, and no medical, dosing or weight-loss guidance is provided with them.