What Is Tirzepatide?
The dual GLP-1 / GIP agonist explained — mechanism and lab handling.
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Compound guide
What Is Semaglutide?
The original of the GLP-1 family and the most studied of the three. Here's what semaglutide is, how it works, and how it's handled in the lab.
If you've heard of any peptide in this family, it's probably semaglutide. It's the longest-studied of the GLP-1 receptor agonists and the reference point everything newer — tirzepatide, retatrutide — gets compared against.
Research use only. This article is an educational overview
of a research compound. It is not medical advice, makes no treatment or dosing
recommendations, and does not describe human use.
What is semaglutide?
Semaglutide is a synthetic peptide that acts as a GLP-1 receptor agonist — it targets a single receptor, GLP-1, which is central to the body's glucose and appetite signalling. It's supplied to researchers as a lyophilized powder and is the most extensively studied compound in the family.
How does it work?
An agonist switches a receptor on. Semaglutide engages the GLP-1 receptor, part of the incretin system — the same signalling pathway that newer dual and triple agonists build on. Because it focuses on one well-characterised target, semaglutide is often the starting point for understanding how this whole class of peptides behaves.
Semaglutide is the single-receptor original; tirzepatide added a second, retatrutide a third.
Semaglutide vs tirzepatide vs retatrutide
| Compound | Type | Receptors |
|---|---|---|
| Semaglutide | Single agonist | GLP-1 |
| Tirzepatide | Dual agonist | GLP-1 + GIP |
| Retatrutide | Triple agonist | GLP-1 + GIP + glucagon |
Being the "simplest" doesn't make semaglutide lesser — it's the most validated and the backbone of the family's research.
How is semaglutide handled in the lab?
- Keep the sealed vial cool, dry, and out of direct light.
- Reconstitute with bacteriostatic water — see how to reconstitute peptides and how much BAC water to use.
- Refrigerate the reconstituted solution, where it stays stable for weeks.
Why purity matters
Confirm what's in the vial before anything else. A reputable source provides a Certificate of Analysis (COA) with third-party HPLC purity and mass-spec identity for that batch — here's how to read one.
Where to buy
Sourcing research-grade semaglutide
We recommend Vital Chems for tested compounds and bacteriostatic water.
- Third-party HPLC tested — COA on every order
- Same-day shipping before 1:30 PM PT
- US-based, fast and responsive support
Frequently asked questions
What is semaglutide?
A synthetic peptide that acts as a GLP-1 receptor agonist — it activates a single receptor, GLP-1. One of the most studied peptides in metabolic research, supplied as a lyophilized powder for research use only.
How is it different from tirzepatide?
Semaglutide targets one receptor (GLP-1); tirzepatide targets two (GLP-1 + GIP), making it a dual agonist.
How is it stored and prepared?
It ships as a freeze-dried powder, kept cool and dry, and is reconstituted with bacteriostatic water before use. After reconstitution it's refrigerated.
Is semaglutide sold for human use?
Material sold for research is supplied and handled for research use only, not for human use.