Vilon

01 · What it is

Vilon is the only compound in the St Petersburg bioregulator programme whose central finding has been pursued for twenty years by a laboratory somewhere else — and that finding concerns the compaction state of chromatin in lymphocytes taken from old donors, which is several steps removed from anything a person would notice.

Vilon is the dipeptide L-lysyl-L-glutamate, written KE in the group’s later papers. Two amino acids. It is the smallest compound in this project, and one of the smallest molecules that anyone has proposed as a therapeutic peptide.

It is also a named component of another compound in this family. A 2023 paper from the developing group states that KE and EW dipeptides are the active substances of Thymalin ²⁶, the thymic extract covered separately in this project. So the Vilon literature and the Thymalin literature are not independent of one another, and no paper in either discusses the overlap. This guide does, because a reader comparing the two should know that one is claimed to be inside the other.

The chromatin work is what makes this guide different from the others in the family. A group at Tbilisi State University led by Teimuraz Lezhava has published on peptide bioregulators and chromatin structure from 2004 to 2023: Vilon-induced reactivation of chromatin in cultured lymphocytes from old people ¹⁰, anti-ageing peptide bioregulators inducing chromatin reactivation ¹⁵, genomic instability in atherosclerosis ²², and epigenetic modification of “old” chromatin under peptide bioregulators ²⁵. Khavinson is a co-author on the first of these and not on the later ones.

Twenty years of work by a separate group in a separate country is the strongest external validation anywhere in this programme. It is also worth being precise about what it validates: that a dipeptide applied to cultured lymphocytes changes how tightly chromatin is packed, measured by cytogenetic and calorimetric methods, in cells from elderly donors. That is a real observation about cells. It is not an observation about people, and the papers do not claim otherwise.

The mechanistic proposal underneath it is unusual and testable. The group’s account is that these very short peptides enter the cell nucleus and bind DNA in a sequence-preferential way, acting as transcriptional regulators. Fluorescence-labelled short peptides were shown to penetrate the nucleus in HeLa cells and to interact specifically with deoxyribooligonucleotides and DNA, in work published with Boris Vanyushin, a DNA methylation researcher at Moscow State University ¹⁸. Molecular docking later identified GCGC in curved nucleosomal DNA as the preferred binding sequence for KE specifically ²⁶.

The human evidence is one Russian-language paper. PubMed indexes a 2007 study of the effect of Vilon on immune status and coagulation haemostasis in patients of different ages with diabetes mellitus, published in Advances in Gerontology and tagged as a clinical trial ¹⁶. This guide has not read that paper — it is in Russian and its abstract is not indexed — and relies on PubMed’s publication-type tag alone for the statement that a human study exists. That reliance is stated here rather than buried, and it is the top item in this guide’s verification queue.

02 · Evidence at a glance

Evidence grade

Early Clinical — one indexed human study, PubMed-tagged as a clinical trial, not read for this guide ¹⁶

Structure

L-Lys-L-Glu; a dipeptide, written KE

Relationship to Thymalin

Named by the developing group as one of Thymalin’s two active substances ²⁶

Proposed mechanism

Nuclear penetration and sequence-preferential DNA binding ^18,26

Independent research line

Chromatin reactivation, Tbilisi State University, 2004–2023 ^10,15,22,25

Animal lifespan data

Mice — biological age and lifespan ⁴; spontaneous tumour growth and lifespan ³

Animal cancer data

Spontaneous tumours in mice ³; DMH-induced neoplasia in rats ¹⁴; with cyclophosphamide ⁹

Human cell work

Lymphocyte chromatin from elderly donors ^10,11; thymus cell cultures ²¹; nucleolar organizer regions ¹²

Human clinical reports

One indexed ¹⁶; a Russian-language review of clinical results ²⁰

Randomised controlled trials

None identified

Approval status

Not approved in the US or EU; Russian status not verified for this guide

03 · Mechanism of action

The DNA-binding hypothesis

The programme’s unifying mechanistic claim is that peptides of two to four residues are small enough to enter the nucleus and bind DNA directly, at preferred sequences, and thereby regulate transcription. It is an unusual proposal — most regulatory peptides act at cell-surface receptors — and it has the merit of being testable by physical methods rather than by phenotype.

Two lines of work support it. Fluorescence-labelled short peptides were shown to penetrate the nucleus in HeLa cells, with specific in vitro interaction between the peptides and deoxyribooligonucleotides and DNA ¹⁸. And molecular docking on the two dipeptides of Thymalin found GGAG in classical B-form DNA to be the preferred sequence for EW, and GCGC in curved nucleosomal DNA for KE — that is, for Vilon ²⁶.

A dipeptide binding a four-base sequence would have very low specificity by the standards of any DNA-binding protein, and neither paper addresses what that implies for selectivity. The mechanism is the most interesting thing in this file and the part most in need of work by someone else.

Chromatin decondensation

The downstream claim follows from the first: if these peptides act on DNA, the observable consequence should be a change in chromatin state. Vilon induced reactivation of chromatin in cultured lymphocytes from old people ¹⁰, an effect subsequently described for peptide bioregulators generally ^15,25. The group’s own parallel work reported effects of short peptides on lymphocyte chromatin in senile subjects ¹¹.

Related work examined argyrophilic protein expression in the nucleolar organizer regions of human thymocytes and thymic epitheliocytes cocultured with Vilon and Epithalon ¹² — a nucleolar rather than a chromatin readout, in the same conceptual space.

Heterochromatin in cells from elderly donors is more condensed than in young donors, and a compound that decondenses it is doing something measurable. Whether decondensing it is good is a separate question the literature does not take up, and genomic instability is one of the things this group studies in the same system ²².

Gene expression

DNA-microarray analysis compared Vilon and Epithalon effects on gene expression in mouse heart ⁶. Later work reported that peptides stimulate cell differentiation tissue-specifically during cellular ageing ¹⁹.

Immune effects

Vilon comes out of a thymic programme, and the earliest work in this line concerns thymic peptide fractions in organ culture ² and thymic peptides as immunomodulators generally ¹. Vilon and an analogue showed immunomodulating effects in cultures of human and animal thymus cells ²¹. The group’s framing of tissue-specificity — that a peptide extracted from a tissue acts on that tissue — is set out in a short 2001 paper ⁵.

04 · Key research findings

Lifespan and tumours in mice. A synthetic dipeptide Vilon inhibited growth of spontaneous tumours and increased lifespan in mice ³ — a paper for which PubMed carries no abstract, so this guide can report only its title and cannot report its methods or effect sizes. Vilon’s effect on biological age and lifespan in mice was reported separately with an abstract ⁴.

One of the two foundational animal results is a title without an abstract. That is a real limitation on what can be said about it, and it is stated rather than glossed.

Carcinogenesis. Vilon affected 1,2-dimethylhydrazine-induced neoplasia in rats ¹⁴, and its combined effect with cyclophosphamide was studied on tumour transplants and lymphoid tissue explants in mice and rats of different ages ⁹. Both are in Russian.

Chromatin, and the twenty-year external line. Vilon reactivated chromatin in cultured lymphocytes from old people ¹⁰. The same laboratory extended the finding to peptide bioregulators as a class ¹⁵, applied the framework to genomic instability in atherosclerosis ²², and in 2023 published on epigenetic modification of “old” chromatin under peptide bioregulators ²⁵.

This is the closest thing to independent replication anywhere in the St Petersburg programme: a different laboratory, a different country, four papers across nineteen years, with the originating group co-authoring only the first. It concerns chromatin in cultured cells.

Intestinal physiology in aged rats. Vilon and Epithalon affected glucose and glycine absorption across regions of the small intestine in aged rats ⁷, and enzyme activity in the epithelial and subepithelial layers of the small intestine in old rats ⁸.

Radiation and metals. Vilon’s effect on the consequences of repeated low-dose radioactive and mercuric exposure was examined in Russian-language work ¹³, alongside antihypoxic properties of short peptides more generally ¹⁷.

Other animal work. Vilon was among the treatments compared for experimental endometriosis in rats ²³.

Human reports. The immune status and coagulation haemostasis study in patients with diabetes mellitus ¹⁶ is the only indexed human study. A Russian-language review titled as reporting clinical study results for peptide bioregulators as a class covers this territory ²⁰, as does a 2020 review of bioregulatory therapy in dental disease ²⁴. None of these is retrievable in English at this guide’s citation standard.

Three of the four human-facing citations in this file are Russian-language reviews or reports whose abstracts are not indexed. That is reported here as the state of the evidence, not worked around.

Contemporary appraisal. A 2026 review of therapeutic peptides in gerontology surveys this class ²⁷.

05 · Evidence overview

06 · Safety profile

Animal data. No formal toxicology programme is identified. The animal work reports lifespan, tumour incidence, intestinal physiology and radiation endpoints ^{3,4,7,8,13,14,23}, none designed to find a toxic dose. Vilon was studied in combination with cyclophosphamide ⁹, which is the only indexed interaction work.

Human data. One indexed study, in patients with diabetes mellitus, reporting immune and coagulation endpoints ¹⁶. It has not been read for this guide. No adverse event data is available from the indexed record.

What is genuinely unknown. Pharmacokinetics of a dipeptide administered by any route: a two-residue peptide is a substrate for ubiquitous peptidases, and nothing in the indexed record reports a plasma concentration, a half-life, or evidence that intact Vilon reaches any tissue after administration. Whether the nuclear penetration observed with fluorescence-labelled peptide in HeLa cells ¹⁸ occurs after systemic dosing in an animal. The selectivity of a dipeptide–DNA interaction, which docking places at a four-base preference ²⁶ — a level of specificity that would engage an enormous number of genomic sites. Whether chromatin decondensation in cells from elderly donors ¹⁰ is beneficial, neutral or harmful, given that the same research line studies genomic instability ²². Repeat-dose toxicology, genotoxicity, reproductive toxicology and carcinogenicity: none performed. Immunogenicity, unassessed. And the composition of any commercial preparation, on which no published analysis exists.

There is one additional unknown specific to this compound. If KE is genuinely an active substance of Thymalin ²⁶, then anyone taking both is taking the same molecule twice, and no paper in either literature addresses that.

07 · US regulatory status

Current as of 6 September 2026. Vilon is not approved as a drug in the United States or the European Union and is not a controlled substance in the United States.

The compound has a history of use within the Russian medical system, and a Russian-language review describes clinical study results for this class of bioregulators ²⁰. This guide does not state whether Vilon holds a Russian marketing authorisation, because establishing that would require Russian regulatory records that have not been consulted. The same qualification applies to Thymalin and is logged for both.

Under the World Anti-Doping Code, substances not approved for human therapeutic use by any governmental regulatory health authority fall within class S0. Competitors should consult the current Prohibited List directly rather than rely on secondary summaries, including this one.

08 · Limitations of the evidence

1. The human evidence is one paper this guide has not read. PubMed tags PMID 18306698 as a clinical trial ¹⁶; its abstract is not indexed and its text is in Russian. The Early Clinical grade rests entirely on a database tag. That is stated in Section 1, in Section 2 and here, and it is the first item in the verification queue.
2. A foundational animal paper has no abstract. The report that Vilon inhibits spontaneous tumour growth and increases lifespan in mice ³ is indexed with title and citation only. Its design, its n, its effect size and its statistics are all unavailable, and this guide cites it as a title rather than as a result.
3. Language and venue restrict scrutiny. Seven of the twenty-seven references are Russian-language ^{9,13,14,16,20,22,24}, and much of the remainder appears in Bulletin of Experimental Biology and Medicine and Advances in Gerontology. A reader wishing to check this guide against its sources will not be able to check a substantial fraction of them.
4. Research concentration remains high despite the external chromatin line. The Tbilisi group’s work is genuinely separate ^15,22,25, and it addresses one narrow phenotype in cultured cells. Every animal result, every human report and every mechanistic claim about nuclear penetration originates with the St Petersburg programme.
5. Chromatin decondensation in cultured lymphocytes is a long way from a clinical effect. Four papers over nineteen years establish that something happens to chromatin in cells from old donors ^10,15,22,25. Nothing connects that to an outcome in an organism.
6. The DNA-binding mechanism implies very low specificity and the literature does not address it. A dipeptide with a preference for a four-base motif ²⁶ would bind at an enormous number of genomic positions. No paper estimates the number of sites, the occupancy, or what selectivity would have to exist for the proposed regulation to be meaningful.
7. Pharmacokinetics are entirely absent for a molecule with an obvious pharmacokinetic problem. A dipeptide is cleaved by peptidases present in plasma, gut and every tissue. Nothing in this literature demonstrates that administered Vilon survives to reach a nucleus.
8. The overlap with Thymalin is unexamined. If Vilon is one of Thymalin’s active substances ²⁶, results attributed to the two compounds are not independent evidence, and the literature treats them as though they were.
9. No randomised controlled trial exists in any species for any endpoint.
10. Nothing is known about commercial material. No published analysis has examined any product sold as Vilon.

09 · References

1. Morozov VG, Khavinson VK. Natural and synthetic thymic peptides as therapeutics for immune dysfunction. Int J Immunopharmacol. 1997 Sep–Oct;19(9–10):501–505.

   PMID 9637345 ↗

2. Chalisova NI, Khavinson VKh, Penniiaĭnen VA, Grigor’ev EI. [Effect of thymus polypeptide fractions on the development of rat thymus and spleen in organ culture]. Tsitologiia. 1999;41(10):889–894. Russian.

   PMID 10591126 ↗

3. Khavinson VKh, Anisimov VN. A synthetic dipeptide vilon (L-Lys-L-Glu) inhibits growth of spontaneous tumors and increases life span of mice. Dokl Biol Sci. 2000 May–Jun;372:261–263. No abstract available.

   PMID 10944717 ↗

4. Khavinson VK, Anisimov VN, Zavarzina NY, et al. Effect of vilon on biological age and lifespan in mice. Bull Exp Biol Med. 2000 Jul;130(7):687–690.

   PMID 11140587 ↗

5. Khavinson VK. Tissue-specific effects of peptides. Bull Exp Biol Med. 2001 Aug;132(2):807–808.

   PMID 11713572 ↗

6. Anisimov SV, Bokheler KR, Khavinson VKh, Anisimov VN. Studies of the effects of Vilon and Epithalon on gene expression in mouse heart using DNA-microarray technology. Bull Exp Biol Med. 2002 Mar;133(3):293–299.

   PMID 12360356 ↗

7. Khavinson VKh, Egorova VV, Timofeeva NM, Malinin VV, Gordova LA, Gromova LV. Effect of Vilon and Epithalon on glucose and glycine absorption in various regions of small intestine in aged rats. Bull Exp Biol Med. 2002 May;133(5):494–496.

   PMID 12420071 ↗

8. Khavinson VKh, Timofeeva NM, Malinin VV, Gordova LA, Nikitina AA. Effect of vilon and epithalon on activity of enzymes in epithelial and subepithelial layers in small intestine of old rats. Bull Exp Biol Med. 2002 Dec;134(6):562–564.

   PMID 12660839 ↗

9. Barykina OP, Iuzhakov VV, Chalisova NI, Kvetnoĭ IM, Konovalov SS. [Combined effect of vilon and cyclophosphane on tumor transplants and lymphoid tissue explants in mice and rats of various age]. Adv Gerontol. 2003;12:128–131. Russian.

   PMID 14743610 ↗

10. Lezhava T, Khavison V, Monaselidze J, Jokhadze T, Dvalishvili N, Bablishvili N, Barbakadze S. Bioregulator Vilon-induced reactivation of chromatin in cultured lymphocytes from old people. Biogerontology. 2004;5(2):73–79.

    PMID 15105581 ↗

11. Khavinson VKh, Lezhava TA, Malinin VV. Effects of short peptides on lymphocyte chromatin in senile subjects. Bull Exp Biol Med. 2004 Jan;137(1):78–81.

    PMID 15085253 ↗

12. Raikhlin NT, Bukaeva IA, Smirnova EA, et al. Expression of argyrophilic proteins in the nucleolar organizer regions of human thymocytes and thymic epitheliocytes under conditions of coculturing with vilon and epithalon peptides. Bull Exp Biol Med. 2004 Jun;137(6):588–591.

    PMID 15455093 ↗

13. Ivanov SD, Khavinson VKh, Malinin VV, Kovan’ko EG, Iamshanov VA, Kondrat’eva AV, Morozov VG. [Vilon effect on consequences of repeated radioactive and mercuric impact in small doses]. Adv Gerontol. 2005;16:88–91. Russian.

    PMID 16075682 ↗

14. Pliss GB, Mel’nikov AS, Malinin VV, Khavinson VKh. [The effect of vilon (Lys-Glu) on 1,2-dimethylhydrazine-induced neoplasia]. Vopr Onkol. 2005;51(4):466–469. Russian.

    PMID 16308980 ↗

15. Lezhava T, Monaselidze J, Kadotani T, Dvalishvili N, Buadze T. Anti-aging peptide bioregulators induce reactivation of chromatin. Georgian Med News. 2006 Apr;(133):111–115.

    PMID 16705247 ↗

16. Kuznik BI, Isakova NV, Kliuchereva NN, Maleeva NV, Pinelis IS. [Effect of vilon on the immunity status and coagulation hemostasis in patients of different age with diabetes mellitus]. Adv Gerontol. 2007;20(2):106–115. Clinical trial. Russian.

    PMID 18306698 ↗

17. Kozina LS. [Investigation of antihypoxic properties of short peptides]. Adv Gerontol. 2008;21(1):61–67. Russian.

    PMID 18546825 ↗

18. Fedoreyeva LI, Kireev II, Khavinson VKh, Vanyushin BF. Penetration of short fluorescence-labeled peptides into the nucleus in HeLa cells and in vitro specific interaction of the peptides with deoxyribooligonucleotides and DNA. Biochemistry (Mosc). 2011 Nov;76(11):1210–1219.

    PMID 22117547 ↗

19. Khavinson VKh, Linkova NS, Polyakova VO, Kheifets OV, Tarnovskaya SI, Kvetnoy IM. Peptides tissue-specifically stimulate cell differentiation during their aging. Bull Exp Biol Med. 2012 May;153(1):148–151.

    PMID 22808515 ↗

20. Khavinson VKh, Kuznik BI, Ryzhak GA. [Peptide bioregulators: the new class of geroprotectors. Message 2. Clinical studies results]. Adv Gerontol. 2013;26(1):20–37. Review. Russian.

    PMID 24003726 ↗

21. Sevostianova NN, Linkova NS, Polyakova VO, et al. Immunomodulating effects of Vilon and its analogue in the culture of human and animal thymus cells. Bull Exp Biol Med. 2013 Feb;154(4):562–565.

    PMID 23486604 ↗

22. Dzhokhadze TA, Buadze TZh, Gaiozishvili MN, Kakauridze NG, Lezhava TA. [Genomic instability in atherosclerosis]. Georgian Med News. 2014 Nov;(236):82–86. Russian.

    PMID 25541832 ↗

23. Aleksinskaya ES, Nazarov SB, Posiseeva LV, Nazarova AO, Malyshkina AI. Comparison of treatment options for experimental endometriosis in rats. Bull Exp Biol Med. 2015 Mar;158(5):681–683.

    PMID 25778659 ↗

24. Pinelis IS, Pinelis YI, Kuznik BI, Iordanishvili AK, Vasiliev MA. [Age features of bioregulatory therapy of dental diseases]. Adv Gerontol. 2020;33(1):137–152. Russian.

    PMID 32362097 ↗

25. Lezhava T, Jokhadze T, Monaselidze J, et al. Epigenetic modification under the influence of peptide bioregulators on the “old” chromatin. Georgian Med News. 2023 Feb;(335):79–83.

    PMID 37042594 ↗

26. Linkova N, Khavinson V, Diatlova A, Petukhov M, Vladimirova E, Sukhareva M, Ilina A. The influence of KE and EW dipeptides in the composition of the Thymalin drug on gene expression and protein synthesis involved in the pathogenesis of COVID-19. Int J Mol Sci. 2023 Aug 29;24(17):13377.

    PMID 37686182 ↗

27. Mavrych V, Shypilova I, Bolgova O. Therapeutic peptides in gerontology: mechanisms and applications for healthy aging. Front Aging. 2026 Apr 7;7:1790247.

    PMID 42021992 ↗