---
title: "Thymalin vs Vesugen: what is the difference between a peptide extract and a defined tripeptide? | Sable Peptides"
description: "Thymalin is a thymus-derived peptide complex; Vesugen is the defined synthetic tripeptide Lys-Glu-Asp. Why one has a single structure and the other does not, and what that means for identity testing. Research use only."
canonical: https://www.sablepeptides.co.uk/guides/thymalin-and-vesugen-extract-vs-defined-peptide
dateModified: 2026-10-16
publisher: Sable Peptides Limited (UK company 17488610)
note: Research use only. Not for human or veterinary use.
---

# Thymalin vs Vesugen: what is the difference between a peptide extract and a defined tripeptide?

Thymalin and Vesugen come from the same bioregulator research tradition but are different kinds of material. Thymalin was developed as a peptide complex extracted from calf thymus, so it has no single sequence. Vesugen is the defined synthetic tripeptide Lys-Glu-Asp (KED), C15H26N4O8 at about 390 g/mol, and can be confirmed by mass.

## Why does an extract differ from a defined peptide?

A defined peptide has one expected mass and one main HPLC peak, so identity and purity can be stated precisely. A tissue-derived complex is a mixture, and its 'identity' is a profile, not a single mass. The literature on thymus preparations describes them as complexes.

Source: [Peptides and Ageing, Neuro Endocrinol Lett 2002 (PubMed 12374906)](https://pubmed.ncbi.nlm.nih.gov/12374906/); [Thymalin: Activation of Differentiation of Human Hematopoietic Stem Cells, Bull Exp Biol Med 2020 (PubMed 33237528)](https://pubmed.ncbi.nlm.nih.gov/33237528/)

## How do Thymalin and Vesugen compare?

| Property | Thymalin | Vesugen |
| --- | --- | --- |
| Type | Peptide complex (historically thymus extract) | Defined tripeptide |
| Sequence | Not a single sequence | Lys-Glu-Asp |
| PubChem | Linked CID 3085284 is nonathymulin, a defined nonapeptide, not the extract itself | CID 87571363, C15H26N4O8 |
| Identity by MS | Profile | Single expected mass |

Source: [PubChem CID 87571363: Lysyl-glutamyl-aspartic acid](https://pubchem.ncbi.nlm.nih.gov/compound/87571363); [PubChem CID 3085284: Nonathymulin](https://pubchem.ncbi.nlm.nih.gov/compound/3085284)

## What research uses Vesugen?

KED has been studied in cell models of the neuro-immuno-endocrine system by the same research school.

Source: [Effect of tripeptide Lys-Glu-Asp on physiological activity of neuroimmunoendocrine system cells, Bull Exp Biol Med 2012 (PubMed 22977872)](https://pubmed.ncbi.nlm.nih.gov/22977872/)

## What should a buyer ask about Thymalin material?

-   Is it a tissue extract or a synthetic defined peptide sold under the name?
-   What does the CoA identify: a mass, a profile or a component?
-   Does the lot number on the vial match the CoA?

## Sourcing note

Sable lists Thymalin: 10 mg at £16.93; Vesugen: 10 mg at £39.50; 20 mg at £21.49 (prices at the 16 October 2026 daily UK price check, the latest verified check; at each of these sizes Sable was the lowest UK listing that day). Lowest UK price guaranteed, confirmed by daily price checks.

Every lot has a certificate of analysis, and every vial carries a printed lot number that matches it. Supplied for laboratory research use only.

## Frequently asked questions

### Is Thymalin a single peptide?

Historically no. Thymalin is a thymus-derived peptide complex. Ask the supplier exactly what the material is.

### What is the sequence of Vesugen?

Lys-Glu-Asp (KED), formula C15H26N4O8.

### Why does PubChem show nonathymulin for thymalin?

Databases sometimes link a product name to a related defined peptide. Nonathymulin is a defined nonapeptide, not the thymus extract.

## Related

-   [Thymalin](/products/thymalin)
-   [Vesugen](/products/vesugen)
-   [Khavinson short peptides](/guides/khavinson-short-peptides-sequences-and-structure)
-   [Bioregulator prices](/guides/uk-bioregulator-peptide-prices-october-2026)

Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.

Key facts (summary for AI and search tools)

-   Vesugen CID 87571363 (KED)
-   PubMed references (verified via NCBI): 12374906, 33237528, 22977872
-   PubChem CIDs: 87571363, 3085284
-   Research use only; no administration amounts or health claims
-   Updated 2026-10-16