---
title: "What is the molecular weight of semaglutide? | Sable Peptides"
description: "The molecular weight of Semaglutide is 4114.0 g/mol on the registry record used for identity. The molecular formula is C187H291N45O59."
canonical: https://www.sablepeptides.co.uk/questions/semaglutide-molecular-weight
publisher: Sable Peptides Limited (UK company 17488610)
note: Research use only. Not for human or veterinary use.
---

# What is the molecular weight of semaglutide?

The molecular weight of Semaglutide is 4114.0 g/mol on the registry record used for identity. The molecular formula is C187H291N45O59. CAS Registry Number 910463-68-2. PubChem CID 56843331. It is classed as a peptide (lipidated). Synonyms include GLP-1 analogue with C18 fatty diacid side chain.

Mass. The expected average mass for identity confirmation is 4114.0 g/mol.

Formula. C187H291N45O59.

Analytical note. Sable's release specification is ≥99% by HPLC with identity confirmed against the expected mass (quality page). Research use only. Not a medicine. Not for human or veterinary use.

## Sources

-   [https://pubchem.ncbi.nlm.nih.gov/compound/56843331](https://pubchem.ncbi.nlm.nih.gov/compound/56843331)

## Semaglutide: reference facts

7 Semaglutide values, each linked to its public source; see the [Semaglutide reference page](/ref/semaglutide).

| Synonyms | GLP-1 analogue with C18 fatty diacid side chain (pubchem.ncbi.nlm.nih.gov) |
| --- | --- |
| Compound class | peptide (lipidated) (pubchem.ncbi.nlm.nih.gov) |
| CAS Registry Number | 910463-68-2 (pubchem.ncbi.nlm.nih.gov) |
| Molecular formula | C187H291N45O59 (pubchem.ncbi.nlm.nih.gov) |
| Molecular weight | 4114.0 g/mol (pubchem.ncbi.nlm.nih.gov) |
| PubChem CID | 56843331 (pubchem.ncbi.nlm.nih.gov) |
| Storage (lyophilised) | -20 °C, dry, protected from light (sigmaaldrich.com) |

## Sizes and prices at Sable

| Vial | Price | Per mg | UK same-size check (2026-10-16) |
| --- | --- | --- | --- |
| 1 mg | £21.49 | £21.49 | no same-size match |
| 2 mg | £34.99 | £17.50 | no same-size match |
| 5 mg | £28.98 | £5.80 | no same-size match |
| 8 mg | £66.49 | £8.31 | no same-size match |
| 10 mg | £38.98 | £3.90 | no same-size match |
| 20 mg | £64.98 | £3.25 | no same-size match |
| 30 mg | £84.98 | £2.83 | no same-size match |

Multi-vial pricing on the same item: 3+ vials 10% off, 5+ vials 15% off, 10+ vials 20% off. Every lot has a certificate of analysis: [CoA library](/coa).

## Typical analytical method

| HPLC column | C18 reversed-phase (300 A pore, C4/C8 suitable for large/lipidated) |
| --- | --- |
| Mobile phase | A: water + 0.1% TFA; B: acetonitrile + 0.1% TFA; linear gradient (e.g. 5-65% B over 20-30 min) |
| Detection | 214-220 nm (peptide bond) |

General literature method. The lot CoA records the method actually used. [How to read an HPLC chromatogram](/learn/how-to-read-an-hplc-chromatogram).

## Related questions

-   [What is the molecular formula of semaglutide?](/questions/semaglutide-molecular-formula)
-   [What does Semaglutide dissolve in?](/questions/semaglutide-solubility)
-   [How stable is lyophilised Semaglutide?](/questions/semaglutide-stability-lyophilised)

## Lyophilised storage on file: Semaglutide

From the Sable storage reference (lyophilised material only; temperature, light, moisture). Literature basis is linked per row. See [peptide storage](/learn/peptide-storage-and-solubility).

| Compound | Lyophilised storage | Light / notes |
| --- | --- | --- |
| Semaglutide | -20 C long term (-80 C acceptable), sealed and desiccated; 2-8 C for weeks | protect from light; no specific sequence liabilities identified from sequence data on file (source) |

## Typical analytical method: Semaglutide

Reference HPLC and MS conditions from the Sable analytical-methods file; a lot's CoA states the method actually used. See [how to read a CoA](/guides/how-to-read-a-coa).

| Compound | HPLC column / detection | MS / expected ion |
| --- | --- | --- |
| Semaglutide | C18 reversed-phase (300 A pore, C4/C8 suitable for large/lipidated); 214-220 nm (peptide bond) | ESI-MS (positive mode); LC-MS for identity; [M+3H]3+ ~1372.3; [M+4H]4+ ~1029.5; [M+5H]5+ ~823.8; [M+6H]6+ ~686.7 |

Research use only. Not a medicine. Not for human or veterinary use.