Five of the six Khavinson-series peptides in the catalogue are defined short peptides that differ by one or two residues, and the sixth, Thymalin, is a name that historically describes an extract. Vilon is the dipeptide Lys-Glu. Add an aspartate and it is Vesugen. Add a glycine to that and it is Testagen; add a proline instead and it is Prostamax. Pinealon is a different tripeptide, Glu-Asp-Arg. This post puts all six side by side with formula, mass, current lot and certificate, because the series is sold on tissue names and bought on sequences, and the two do not always line up. The evidence for the series is covered separately in the Khavinson evidence post and the origin of the term in what a peptide bioregulator is.
What are the six, in one table?
| Product | Sequence | Residues | Formula | Mass (g/mol) | Catalogue vial | Current lot | Certificate |
|---|---|---|---|---|---|---|---|
| Vilon | Lys-Glu (KE) | 2 | C11H21N3O5 | 275.3 | 20 mg | VILON20-0528 | COA4861, 17 Jun 2026 |
| Vesugen | Lys-Glu-Asp (KED) | 3 | C15H26N4O8 | 390.4 | 20 mg | VESU20-0528 | COA4865, 17 Jun 2026 |
| Testagen | Lys-Glu-Asp-Gly (KEDG) | 4 | C17H29N5O9 | 447.4 | 20 mg | TESTA20-0528 | COA4864, 17 Jun 2026 |
| Prostamax | Lys-Glu-Asp-Pro (KEDP) | 4 | C20H33N5O9 | 487.5 | 20 mg | PROS20-0318 | COA3398, 3 Apr 2026 |
| Pinealon | Glu-Asp-Arg (EDR) | 3 | C15H26N6O8 | 418.4 | 20 mg | PINE20-0803 | COA7610, 17 Aug 2026 |
| Thymalin | See below | See below | Not stated | 858.8 observed | 20 mg | THYM20-0318 | COA3390, 3 Apr 2026 |
Epithalon, Ala-Glu-Asp-Gly, belongs to the same series and has its own coverage in the evidence post; it is included in the arithmetic below for comparison.
Why do the sequences look so alike?
Because the series was built that way. The Khavinson group derived short peptides from tissue extracts and then synthesised the shortest sequences they reported as active, and those sequences are built from a small set of acidic and basic residues: lysine, glutamate, aspartate, with glycine, proline, alanine or arginine as the variable position. Testagen and Prostamax are the same three residues with a different fourth. Vesugen is those three residues alone. Vilon is the first two.
That has a practical consequence. Two of these compounds cannot be told apart by appearance, by solubility, or by anything short of a mass measurement. Testagen (447.4) and Prostamax (487.5) differ by 40 mass units; either is unambiguous by mass spectrometry, and neither is distinguishable on the bench. The certificate's identity line is the only evidence of which one is in the vial, and the tripeptide certificate post explains why identity by mass matters more for very short peptides than for long ones.
How many molecules are in a 20 mg vial?
More than for any other compound class in the catalogue, because the masses are so small. Dividing the vial mass by the molar mass:
| Product | Mass (g/mol) | 20 mg is | In 2 mL that is |
|---|---|---|---|
| Vilon | 275.3 | 72.6 µmol | 36 mM |
| Vesugen | 390.4 | 51.2 µmol | 26 mM |
| Epithalon (10 mg vial) | 390.3 | 25.6 µmol | 13 mM |
| Pinealon | 418.4 | 47.8 µmol | 24 mM |
| Testagen | 447.4 | 44.7 µmol | 22 mM |
| Prostamax | 487.5 | 41.0 µmol | 21 mM |
For comparison, 10 mg of a 3.4 kDa GHRH analogue is about 3 µmol. A study that uses these compounds at the same mass concentration as a larger peptide is using ten to twenty times the molar concentration, which is the point the molarity post makes in general and which matters most here.
What does each certificate report?
All six current certificates were issued by Bioviridian Inc. and are published unaltered on the certificate page. The tests differ by certificate layout, not by compound: the April 2026 certificates report identity, content, purity and endotoxin; the June 2026 certificates add heavy metals and sterility; the August 2026 certificates add heavy metals.
| Product | Identity method | Content | Purity (RP-HPLC, 214 nm) | Endotoxin | Extra tests |
|---|---|---|---|---|---|
| Vilon | MALDI-MS, 275.3 | 20.13 mg | 99.9% | < 0.05 EU/mL | Heavy metals, sterility |
| Vesugen | MALDI-MS, 390.4 | 20.64 mg | 99.9% | < 0.05 EU/mL | Heavy metals, sterility |
| Testagen | MALDI-MS, 447.4 | 20.32 mg | 99.9% | < 0.05 EU/mL | Heavy metals, sterility |
| Prostamax | MALDI-MS, 487.5 | 12.82 mg (10 mg sample) | 99.9% | ≤ 0.05 EU/mL | None |
| Pinealon | LC-MS/MS, 418.4 | 20.80 mg | 99.68% | < 0.05 EU/mL | Heavy metals |
| Thymalin | MALDI-MS, 858.8 | 18.79 mg | 99.8% | ≤ 0.05 EU/mL | None |
Two lines in that table deserve a sentence each.
Prostamax. The certificate's sample line reads "Prostamax 10mg" and the content result is 12.82 mg, while the catalogue vial is 20 mg. The certificate is genuine and the lot number matches; what it certifies is a 10 mg sample from that lot. Before relying on the content figure for a 20 mg vial, check that the lot number on the vial is PROS20-0318 and treat the certificate as evidence of identity and purity for the lot, not of the fill in your particular vial. This is exactly the kind of mismatch the supplier-vetting post says to look for, and it is stated here rather than smoothed over.
Thymalin. The name comes from a thymic extract described in the 1970s, and the product copy says so. The current certificate, however, reports a single observed mass of 858.8 by MALDI-MS and a purity of 99.8% by HPLC, which is what a defined synthetic peptide looks like, not a mixture. The sensible reading is that the material tested is a single synthetic sequence sold under the extract's name. Record the certificate's observed mass in the methods section and do not describe the material as an extract, because the certificate says it is not one.
What should you check before ordering any of them?
- The sequence on the product page. Four of the five defined peptides share three residues. Make sure the page names the fourth.
- The certificate's identity mass against the table above. A 447 where you expected 488 is a different compound.
- The lot number on the certificate against the lot you will receive, since certificates in this series span April, June and August 2026 layouts with different test panels.
- The endotoxin line if the compound is going into cell work; all six report at or below 0.05 EU/mL, and the endotoxin post explains the units.
- Molar arithmetic before choosing a vial size, using the table above; the vial-size post covers the general case.
How should they be handled?
As very short, very polar peptides. They dissolve quickly in water, they do not aggregate in the way the aggregation post describes for longer sequences, and they are hygroscopic as dry powders, so keep the vial sealed until it is at room temperature. The dipeptide and tripeptides have free N-terminal amines and C-terminal carboxylates, and the glutamate and aspartate side chains are charged at neutral pH, so solubility is not a concern and adsorption to plastic is minimal. The storage guide windows apply; the reconstituted-lifetime post gives the reasons short peptides sit at the longer end of them.
Frequently asked questions
Are these the same peptides that appear in the Khavinson papers?
By sequence, yes, for the five defined compounds: KE, KED, KEDG, KEDP and EDR are the sequences the published work names. Whether a given vial is that sequence is what the certificate's identity line answers.
Why are Testagen and Prostamax priced the same when they differ by one residue?
Because a residue's cost in solid-phase synthesis is small against the fixed costs of the run, purification and testing. The prices post explains where the money goes at this scale.
Can I tell Vesugen from Testagen by dissolving them?
No. Both dissolve immediately in water and give a clear, colourless solution. Only a mass measurement separates them, which is why the certificate matters more for these than for compounds with distinctive physical properties.
Is Thymalin a single peptide or a mixture?
The current certificate reports one observed mass, 858.8, and a single-peak purity of 99.8%, which describes a defined compound. The name historically refers to an extract. Cite what the certificate reports, and record the certificate code with it.
Does Pinealon belong with the other five?
It shares the series and the residue set, but its sequence starts with glutamate rather than lysine, so it is not a truncation or extension of the others. Its literature is concentrated in neuronal models, which the Khavinson evidence post discusses.
References
- Khavinson VKh, Linkova NS, Kvetnoy IM, et al. AEDG peptide (epitalon) stimulates gene expression and protein synthesis during neurogenesis. Molecules 2020;25(3):609. doi.org/10.3390/molecules25030609
- Khavinson VKh, Malinin VV. Peptide bioregulators inhibit apoptosis. Bulletin of Experimental Biology and Medicine 2000;130(12):1175-1176. doi.org/10.1007/bf02682019
- Khavinson VKh, et al. Effect of vilon and epithalon on activity of enzymes in epithelial and subepithelial layers in small intestine of old rats. Bulletin of Experimental Biology and Medicine 2002;134(6):562-564. doi.org/10.1023/a:1022913228900
- PubChem, National Library of Medicine. Pinealon CID 10273502; Vilon CID 7010502; Vesugen CID 87571363. Read 27 September 2026. pubchem.ncbi.nlm.nih.gov/compound/10273502
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.
