Vilon

1. Overview

Vilon is a synthetic dipeptide with the amino acid sequence Lys-Glu (KE), consisting of L-lysine linked to L-glutamic acid by a peptide bond, with a molecular weight of 275.30 g/mol (C11H21N3O5; CAS 45234-02-4). It was developed by Vladimir Khavinson at the Saint Petersburg Institute of Bioregulation and Gerontology as the shortest bioactive peptide in the peptide bioregulator program [10] [11].

Vilon was originally identified as one of three principal active components of Thymalin, the bovine thymic extract that was the first peptide bioregulator preparation approved in the USSR (1982). The three identified active peptides of Thymalin are the KE dipeptide (Vilon), the EW dipeptide (Thymogen/L-Glu-L-Trp), and the EDP tripeptide (Crystagen/Glu-Asp-Pro) [15] [17]. Each was subsequently synthesized and studied as a standalone preparation.

As a dipeptide, Vilon represents the minimum peptide length that Khavinson's research has identified as biologically active. Despite its small size (only two amino acid residues), it has demonstrated measurable effects in animal models of aging, carcinogenesis, and immune function, and in ex vivo studies of aged human lymphocyte chromatin [1] [4] [5]. These findings have been cited as support for Khavinson's broader theory that even the shortest peptides can regulate gene expression through direct DNA interaction [8].

Vilon is not registered as a pharmaceutical in any country. It is marketed as a peptide dietary supplement and has not been evaluated by the FDA, EMA, or other Western regulatory agencies.

Sequence

Lys-Glu (KE)

Molecular Weight

275.30 g/mol

Chemical Formula

C11H21N3O5

CAS Number

45234-02-4

Source

Originally isolated from Thymalin (bovine thymic extract); now fully synthetic

Mechanism

Selective DNA binding at TCGA motifs; chromatin remodeling; immune cell gene expression modulation

Routes Studied

Subcutaneous (animal), oral (capsule)

Regulatory Status

Not approved as a pharmaceutical; marketed as a peptide dietary supplement

2. Relationship to Livagen

The user may encounter references suggesting that Vilon and Livagen share the same sequence. This requires clarification:

• Vilon is the dipeptide KE (Lys-Glu) -- two amino acids.
• Livagen is the tetrapeptide KEDA (Lys-Glu-Asp-Ala) -- four amino acids.

While Livagen contains the KE (Vilon) sequence at its N-terminus, it is a distinct, longer molecule. The two peptides share the same first two residues but differ in overall length and claimed tissue specificity. Vilon is designated as a thymic bioregulator for immune function, while Livagen is designated as a hepatic bioregulator for liver function [11] [12]. Whether the additional Asp-Ala residues genuinely redirect tissue targeting from thymus to liver remains mechanistically unvalidated.

Both peptides, along with Vesugen (KED) and Testagen (KEDG), form a structural family sharing the N-terminal lysine-glutamic acid motif, with different claimed organ specificities attributed to their differing C-terminal extensions [8].

3. Mechanism of Action

DNA Binding at TCGA Motifs

The central proposed mechanism for Vilon involves selective binding to TCGA sequences in double-stranded DNA within promoter regions of immune-related genes [8]. Studies using molecular modeling and in vitro DNA interaction assays reported that the KE dipeptide shows energetically favorable binding to specific DNA motifs, potentially modulating transcription of downstream genes involved in immune cell proliferation, differentiation, and cytokine production [8] [9].

Chromatin Remodeling in Aged Cells

A key finding from Vilon research is its ability to reactivate age-compacted chromatin. In cultured lymphocytes from elderly subjects (age 75-88), Vilon induced activation of ribosome genes, decondensation of densely packed heterochromatin fibrils, and release of genes that had been repressed through age-specific chromatin condensation [4] [5]. This chromatin remodeling effect was proposed to reverse the epigenetic silencing that accumulates with aging, restoring a more youthful pattern of gene expression in immune cells.

Immune Cell Modulation

In the THP-1 monocyte/macrophage cell line, Vilon modulated expression of genes associated with proliferative activity and inflammatory pathways, including effects on cytokine balance and apoptosis regulation [6]. In organotypic spleen tissue cultures, Vilon activated T-helper cells through a mechanism involving decreased apoptosis rather than direct enhancement of proliferation [7].

IL-2 Upregulation

In cultured lymphocytes, the KE dipeptide significantly increases IL-2 mRNA expression [6]. IL-2 is the primary autocrine growth factor for T lymphocytes and plays a central role in T-cell clonal expansion, differentiation, and maintenance of regulatory T cells.

Digestive Enzyme Regulation

An additional non-immune effect has been reported: Vilon modulated the activity of digestive enzymes in rats of various ages, suggesting biological activity beyond the immune system [18].

4. Researched Applications

Anti-Tumor Activity and Lifespan Extension

The strongest preclinical evidence for Vilon comes from long-term animal studies:

Spontaneous tumors in CBA mice: Female CBA mice received monthly subcutaneous Vilon injections (0.1 mg/animal, 5 consecutive days per month) from 6 months of age until natural death [1]. Vilon treatment:

• Increased physical activity and endurance
• Decreased body temperature
• Prolonged mean and maximum lifespan
• Prevented development of spontaneous lung adenomas
• Inhibited overall spontaneous tumor growth

Chemically induced carcinogenesis: In mice exposed to the carcinogen 1,2-dimethylhydrazine (DMH), Vilon at 10 mcg/kg reduced tumor incidence from 60% in controls to 14.3% in treated animals at 46 weeks -- a greater than 4-fold reduction [3].

Urinary bladder tumors: In rats with chemically induced urinary bladder tumors, Vilon decreased tumor incidence from 75.5% to 56% and produced a 2-fold decrease in preneoplastic and early neoplastic changes in bladder mucosa [1].

Immune Reconstitution in Aging

Vilon's chromatin reactivation effects in aged lymphocytes [4] [5] and its modulation of immune cell gene expression in the THP-1 model [6] support its proposed application in age-related immune decline. By reversing the heterochromatin condensation that silences immune-related genes with aging, Vilon is proposed to restore more youthful immune function. However, these effects have been demonstrated only in ex vivo and in vitro systems; no controlled clinical trials of Vilon for immune reconstitution in elderly humans have been published.

Spleen Function in Aging

Studies in organotypic spleen tissue cultures from young and old animals demonstrated that Vilon possesses immunoprotective effects in the spleen during aging [7]. Vilon activated T-helper cell function through decreased apoptosis, suggesting a mechanism for maintaining splenic immune competence with advancing age.

Component of Thymalin Therapy

As one of three identified active components of Thymalin [15], Vilon's activity contributes to the therapeutic effects observed in Thymalin clinical studies, including the COVID-19 RCT that demonstrated halved hospital mortality in elderly patients [14] and the long-term elderly mortality reduction studies [14]. However, attributing specific Thymalin effects to Vilon versus EW (Thymogen) or EDP (Crystagen) is not possible from existing data.

5. Clinical Evidence

The clinical evidence for Vilon as a standalone preparation is limited to preclinical data:

Animal Studies: Long-term CBA mouse lifespan studies [1] [2], chemically induced carcinogenesis models [3], and urinary bladder tumor studies provide consistent evidence of anti-tumor and geroprotective effects.

Ex Vivo Human Studies: Chromatin reactivation studies in aged human lymphocytes demonstrate measurable epigenetic effects [4] [5].

In Vitro Studies: THP-1 monocyte/macrophage [6] and organotypic spleen culture [7] studies demonstrate immune-modulating activity.

No human clinical trials of Vilon monotherapy have been published. The human clinical evidence for the KE peptide is indirect, through Thymalin studies where KE is one component of a multi-peptide extract.

6. Dosing in Published Research

The following doses have been reported in published research. These are not recommendations and should not be interpreted as therapeutic guidance.

Animal dosing has ranged from 10 mcg/kg (DMH carcinogenesis model) to 0.1 mg/animal (CBA mice lifespan study). Human-equivalent dosing has not been established through formal pharmacokinetic studies. Supplement formulations typically provide 0.2 mg KE per capsule.

7. Safety and Side Effects

In animal studies spanning lifetime administration, Vilon did not significantly influence body weight or food consumption in mice, and no adverse effects were reported [1] [2]. The compound has been described as well-tolerated across all published studies.

Key safety data gaps include:

• No formal toxicology studies meeting regulatory standards.
• No human safety data from controlled clinical trials.
• No drug interaction studies.
• No pharmacokinetic data (oral bioavailability, half-life, metabolism) in any species.
• No reproductive or developmental toxicity assessment.
• The anti-tumor effects observed in animals, while potentially beneficial, raise questions about effects on normal cell proliferation that have not been systematically evaluated.

8. The Shortest Bioactive Peptide

Vilon holds a unique position in peptide pharmacology as potentially the shortest peptide (two amino acids) demonstrated to produce measurable biological effects in animal models of aging and carcinogenesis. While individual amino acids (e.g., L-glutamic acid, L-tryptophan) have known biological activities, the specific KE dipeptide bond is proposed to create a molecular entity with emergent properties not present in its constituent amino acids alone [8] [10].

This claim is central to Khavinson's theory: if dipeptides can indeed regulate gene expression through direct DNA binding, it would represent a fundamentally new class of regulatory molecules in molecular biology. However, several alternative explanations for observed biological effects have not been fully excluded, including: receptor-mediated signaling through unknown peptide receptors, metabolic effects of the constituent amino acids after peptide bond hydrolysis, and indirect effects through modulation of endogenous peptide processing pathways [13].

9. Limitations and Transparency

• No human clinical trials of Vilon monotherapy have been published.
• All published research originates from Khavinson's institute and affiliated Russian institutions.
• The claim that a dipeptide can function as a tissue-specific gene regulator through direct DNA binding remains unvalidated by independent laboratories.
• The structural similarity between Vilon (KE), Vesugen (KED), Livagen (KEDA), and Testagen (KEDG) raises unresolved questions about the basis for claimed tissue specificity.
• Vilon is marketed as a dietary supplement without pharmaceutical registration in any jurisdiction.
• Separation of Vilon's contribution from those of EW and EDP in Thymalin clinical studies is not possible.

10. Related Peptides

See also: Thymalin, Thymogen, Vesugen, Epithalon

11. References

1. [1] Khavinson VK, Anisimov VN, Zavarzina NY, Zabezhinski MA, Zimina OA, Popovich IG, Rosenfeld SV, Semenchenko AV, Yashin AI (2000). A synthetic dipeptide vilon (L-Lys-L-Glu) inhibits growth of spontaneous tumors and increases life span of mice. Mech Ageing Dev. PubMed
2. [2] Khavinson VK, Anisimov VN (2000). Effect of vilon on biological age and lifespan in mice. Bull Exp Biol Med. PubMed
3. [3] Anisimov VN, Khavinson VK et al. (2005). The effect of vilon (Lys-Glu) on 1,2-dimethylhydrazine-induced neoplasia. Vopr Onkol. PubMed
4. [4] Lezhava TA, Khavinson VK et al. (2004). Bioregulator Vilon-induced reactivation of chromatin in cultured lymphocytes from old people. Biogerontology. PubMed
5. [5] Khavinson VK, Lezhava TA, Malinin VV (2004). Effects of short peptides on lymphocyte chromatin in senile subjects. Bull Exp Biol Med. PubMed
6. [6] Kuznik BI, Linkova NS, Khavinson VK (2022). Peptides regulating proliferative activity and inflammatory pathways in the monocyte/macrophage THP-1 cell line. Int J Mol Sci. DOI PubMed
7. [7] Markova EV, Obukhova LA, Khavinson VK (2014). Peptides regulating proliferative activity in the spleen: age-related molecular aspects. Adv Gerontol. DOI
8. [8] Khavinson VK, Popovich IG, Linkova NS, Mironova ES, Ilina AR (2021). Peptide regulation of gene expression: a systematic review. Molecules. DOI PubMed
9. [9] Fedoreyeva LI, Kireev II, Khavinson VK, Vanyushin BF (2011). 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 (Moscow). DOI PubMed
10. [10] Khavinson VK (2002). Peptides and ageing. Neuro Endocrinol Lett. PubMed
11. [11] Khavinson VK (2020). Peptide medicines: past, present, future. Klin Med (Mosk). PubMed
12. [12] Khavinson VK, Kuznik BI, Ryzhak GA (2013). Peptide bioregulators: a new class of geroprotectors. Report 2. Clinical studies results. Adv Gerontol. PubMed
13. [13] Anisimov VN, Khavinson VK (2010). Peptide bioregulation of aging: results and prospects. Biogerontology. DOI PubMed
14. [14] Khavinson VK, Morozov VG (2003). Peptides of pineal gland and thymus prolong human life. Neuro Endocrinol Lett. PubMed
15. [15] Khavinson VK, Linkova NS, Dyatlova AS, Kuznik BI, Umnov RS (2021). The use of Thymalin for immunocorrection and molecular aspects of biological activity. Biol Bull Rev. DOI PubMed
16. [16] Khavinson VK, Linkova NS, Kvetnoy IM (2020). Peptides: prospects for use in the treatment of COVID-19. Molecules. DOI PubMed
17. [17] Morozov VG, Khavinson VK (1997). Natural and synthetic thymic peptides as therapeutics for immune dysfunction. Int J Immunopharmacol. DOI PubMed
18. [18] Khavinson VK, Malinin VV (2001). Effect of the dipeptide vilon on activity of digestive enzymes in rats of various ages. Bull Exp Biol Med. PubMed