What semaglutide is
Semaglutide is a synthetic analogue of human glucagon-like peptide-1 (GLP-1), modified for resistance to enzymatic degradation and for extended circulation. Two changes do most of the work: substitution at position 8, which protects the molecule from dipeptidyl peptidase-4 (DPP-4) cleavage, and a C18 fatty-diacid conjugate attached via a spacer at position 26, which binds albumin and slows renal clearance.
Native GLP-1 has a circulating half-life measured in minutes. Semaglutide's is measured in days. That difference is entirely a matter of the modifications, not of receptor pharmacology — at the receptor, semaglutide is doing what GLP-1 does.
Molecular profile
| Property | Value |
|---|---|
| CAS number | 910463-68-2 |
| Receptor target | GLP-1R |
| Molecular formula | C187H291N45O59 |
| Molecular weight | ~4,114 Da |
| Key modifications | Aib substitution at position 8; C18 fatty-diacid at position 26 |
| Appearance | White to off-white lyophilised powder |
Research context
Semaglutide is the baseline compound for incretin research. In receptor pharmacology it is used to characterise GLP-1R activation — binding affinity, cAMP accumulation, β-arrestin recruitment, receptor internalisation and recycling. In metabolic models it is the single-agonist comparator that dual (GLP-1/GIP) and triple (GLP-1/GIP/glucagon) agonists are assessed against, which means a substantial proportion of published work on newer compounds includes a semaglutide arm.
Its DPP-4-resistant design also makes it a useful tool for separating questions of receptor pharmacology from questions of pharmacokinetics — a distinction that matters when interpreting why one analogue outperforms another.
Supplied for in-vitro laboratory research only. No therapeutic claim is made and no dosing or administration guidance is provided.
Analytical notes
Semaglutide is one of the most frequently substituted compounds in the research peptide market. The economics are straightforward: demand is high, the material is a white powder indistinguishable from any other white powder, and a customer without analytical capability has no way to check.
Identity confirmation is the control that matters. Mass spectrometry against theoretical mass distinguishes semaglutide from a shorter GLP-1 fragment, from a different analogue in the class, and from material that is largely excipient. A Certificate of Analysis showing purity alone establishes that the vial contains 99% of something.
Purity is about the near-neighbours. The impurity profile of concern is deletion sequences and incompletely conjugated species eluting close to the main peak, which is why the integration window and the chromatogram itself carry more information than the percentage does. See reading an HPLC chromatogram.
Handling and storage
Store sealed at −20 °C, protected from light and moisture, and bring to room temperature before opening. Reconstitute by running diluent down the vial wall and swirling — the C18 conjugate makes this compound interface-sensitive, and shaking is a reliable way to aggregate it. Store solution at 2–8 °C, protected from light, and avoid repeated freeze-thaw cycles.
What we supply
Released against a ≥99% purity specification, with HPLC purity and mass spectrometry identity confirmation on every batch and a batch-specific Certificate of Analysis carrying the vial's batch number. Select batches additionally receive independent third-party purity verification.