Testagen is a tetrapeptide: lysine, glutamic acid, aspartic acid, glycine. Lys-Glu-Asp-Gly, or KEDG. It is one of the short synthetic peptides from the St Petersburg bioregulator programme, sold here as a 20 mg lyophilized vial with a certificate for the lot. The name is the programme's, chosen because the peptide was designed from a testicular extract. The name is not a description of what the peptide does, and this post keeps the two apart.
What follows is the molecule, the certificate line by line, the arithmetic that turns 20 mg into a molar amount, and an honest account of the literature.
What does the sequence tell you?
Four residues with a strong charge pattern: a lysine carrying two positive charges at neutral pH, then two acidic residues, then glycine. Net charge about minus one. Highly polar, completely water-soluble, no aromatic residue and therefore no absorbance at 280 nm, which is why its purity is measured at 214 nm where the peptide bond absorbs.
The sequence shares its Lys-Glu start with vilon, its Lys-Glu-Asp start with vesugen, and its Glu-Asp-Gly ending with epithalon. That family resemblance is not a coincidence. The programme built these peptides from a small set of residues chosen to reflect the composition of organ extracts, and the series comparison shows the overlaps in one table. It also means that a mass spectrometer is the right tool for telling them apart, since several of them would run similarly on a reversed-phase column.
What does the certificate for lot TESTA20-0528 report?
The certificate is COA4864, issued by Bioviridian Inc. on 17 June 2026. Six tests.
| Test | Method | Result |
|---|---|---|
| Identity | MALDI-MS | 447.4 observed |
| Purity | RP-HPLC, 214 nm | 99.9% |
| Content | Gravimetric against label | 20.32 mg against a 20 mg label |
| Endotoxin | LAL | <0.05 EU/mL |
| Heavy metals | ICP | < 0.01 ppm |
| Sterility | Culture | Not detected |
How does 447.4 confirm the sequence?
By arithmetic anyone can repeat. The residues' free masses are lysine 146.19, glutamic acid 147.13, aspartic acid 133.10 and glycine 75.07, which sum to 501.49. Joining four amino acids forms three peptide bonds and each releases one water, 18.02, so subtract 54.05. The result is 447.44. The certificate observed 447.4.
For a tetrapeptide that agreement is strong evidence. The number of four-residue sequences with an average mass within 0.1 of 447.4 is small, and the ones that exist are not products a synthesis of KEDG would make. A single mass does not formally prove the order of the residues, which is why the LC-MS post distinguishes mass identity from sequence identity; but for a defined synthetic product with a matching mass, the order is the one that was made.
How many micromoles is 20 mg?
The label's 20 mg at 447.4 g/mol is 44.7 micromoles. The measured content, 20.32 mg, is the figure to use in a calculation, as the lot-to-lot post recommends. In 1 mL that is a stock near 45 millimolar.
The molarity post has this conversion for every vial in the catalogue, and the concentration table turns it into working dilutions. The short version: 20 mg of a tetrapeptide is an enormous molar amount for in-vitro work, and a single vial typically outlasts a study.
What does the literature contain?
The Khavinson programme's work on testicular-extract peptides, summarised in Anisimov and Khavinson's 2010 review and in the 2005 Karger monograph, which reports effects in aged animals and in cultured cells. The group's general model, that short peptides act on gene expression, is argued across those sources.
What the literature does not contain:
- a receptor for Lys-Glu-Asp-Gly;
- independent replication of the testicular-peptide results outside the programme;
- a registered clinical trial. A search of ClinicalTrials.gov on 2 October 2026 for "testagen" found none.
The bioregulator evidence post is the place for what that profile means when designing around one of these peptides. The name "testagen" invites a reading that the literature does not support; this site does not make it, and the product page says the same.
How is it handled?
- Dissolve in water or buffer. Immediate.
- Degradation routes. Aspartic acid followed by glycine is the classic site for isomerisation to isoaspartate and for succinimide formation, both of which are slow at neutral pH and cold and faster at either pH extreme. Hold stocks near neutral and cold. There is no cysteine, methionine or tryptophan.
- Storage. Lyophilized at minus 20 °C. Solutions aliquoted and frozen.
- Adsorption is minimal for a molecule this charged.
- Diluent. Water or buffer; reconstitution solution only for a preserved multi-entry stock, as the diluent post explains.
Frequently asked questions
Does the certificate state the sequence?
It states an observed mass, 447.4, by MALDI-MS. That mass is what Lys-Glu-Asp-Gly predicts. Mass spectrometry confirms the formula; the sequence is what was synthesised to that formula.
Why no CAS number on the product page?
Because none is recorded in the site's compound data for this peptide, and the site does not add identifiers from memory. The formula, mass and sequence are stated instead.
Is testagen related to vesugen?
They share three residues: vesugen is Lys-Glu-Asp and testagen adds a glycine. Vesugen's certificate mass is 390.4, testagen's 447.4; the difference, 57.0, is one glycine residue. The series comparison shows the whole family.
What is sterility doing on a research certificate?
Reporting that no viable organisms were detected in the cultured sample. It is a third question beside endotoxin and pyrogenicity, which the sterility post separates, and this lot answers all three.
What is testagen sold for?
Laboratory research. Every product on this site is for in-vitro research use only and not for human or animal use.
References
- Anisimov VN, Khavinson VK. Peptide bioregulation of aging: results and prospects. Biogerontology 2010;11(2):139-149. doi.org/10.1007/s10522-009-9249-8
- Khavinson VK, Malinin VV. Gerontological Aspects of Genome Peptide Regulation. Basel: Karger, 2005. doi.org/10.1159/isbn.978-3-318-01204-5
- Bioviridian Inc. Certificate of analysis COA4864, lot TESTA20-0528, issued 17 June 2026. Verification code on the certificate. bioviridians.com/coa-search.html
Every product mentioned is sold for laboratory research use only and is not for human or animal use. Nothing on this page describes or recommends use of the material sold here in humans or animals.
