Vilon (Lys-Glu): Evidence, Mechanism & Legal Status

Vilon is the synthetic dipeptide L-lysyl-L-glutamic acid (Lys-Glu, one-letter 'KE'), one of the ultrashort 'cytogen' peptide bioregulators developed by Vladimir Khavinson's group at the St. Petersburg Institute of Bioregulation and Gerontology as a minimal active fragment of the thymus extract thymalin.6 It is marketed in longevity and immune-support circles as a thymic 'rejuvenation' peptide; its proof in humans is essentially nonexistent. This monograph separates the mechanistic curiosity from the marketing.

This article is informational and editorial content for research and educational purposes only. It is not medical advice, not a protocol to follow, and not a sourcing guide. Vilon is not an FDA-approved drug; it is sold as a 'research chemical not for human use.' Dosing figures are reported strictly as seen in the published literature for completeness — not as recommendations. Consult a licensed clinician before any health decision.

What is Vilon and how is it proposed to work?

Vilon is the synthetic dipeptide L-lysyl-L-glutamic acid (Lys-Glu; molecular weight approximately 275.3 Da) — among the smallest biologically characterized regulatory peptides.6 It was derived from amino-acid analysis of thymalin, a polypeptide thymus extract with prior immunomodulatory use in Russian medicine, with the Khavinson group identifying Lys-Glu as an active short fragment.6

The proposed mechanism is a working hypothesis, not settled science. Unlike classic peptide hormones that act through cell-surface G-protein-coupled receptors, the Khavinson cytogens are proposed to act as epigenetic gene-expression regulators.6 The originating lab proposes a two-track model: direct double-stranded DNA binding — molecular-dynamics modeling places KE in the DNA major and minor grooves at specific short sequences, with the lysine epsilon-amino group engaging the phosphate backbone and the glutamate side chain contacting nucleobases — and histone interaction (H1/H2b/H3/H4), proposed to loosen chromatin and increase promoter accessibility.6 This is mechanistic modeling and in-vitro inference (grade C/D), not validated target engagement. Notably, there is no peer-reviewed human pharmacokinetic dataset for Vilon — no validated half-life, Cmax, clearance, or oral bioavailability; as a small dipeptide it would be expected to be rapidly degraded by peptidases, and published rodent work used the subcutaneous route.4

What is the evidence by indication?

An important framing point governs everything below: essentially all Vilon evidence is preclinical and from a single Russian research lineage (Khavinson, Anisimov and colleagues), concentrated around 2000-2023, with no independent Western replication and no registered randomized controlled trial in humans.6 No indication reaches grade A or B.

The longevity signal is the most cited. In female CBA mice, subcutaneous Vilon from the sixth month of life increased physical activity and endurance, slightly lowered body temperature, prolonged lifespan, and reduced spontaneous neoplasm development, without altering body weight, food intake, estrus function, or free-radical markers.4 Class-level reviews report mean-lifespan extensions on the order of 20-40 percent across Khavinson peptides in rodents.5 A companion paper reported that Vilon 'inhibited growth of spontaneous tumors and increased life span of mice,' reducing spontaneous tumor incidence.3 This is animal data only; it does not establish human geroprotection or any anticancer use.

The mechanistic immune basis is in-vitro. Vilon stimulated IL-2 gene expression in mouse spleen lymphocytes in a concentration- and time-dependent manner, with the authors hypothesizing Lys-Glu is the shortest regulatory fragment promoting nuclear transport of trans-acting factors.1 A follow-up showed Vilon activated IL-2 mRNA synthesis in CBA-mouse splenocytes without specific inductors, Vilon being among the most potent of the peptides tested.2 A 2023 paper reports KE regulates SIRT1, PARP1, PARP2 and PARP3 gene expression in human mesenchymal stem cells, tying it to longevity (SIRT1) and DNA-repair (PARP) pathways.7 These are interesting hypotheses, not human outcomes. Claims of improved T-cell counts or CD4:CD8 ratios in elderly humans circulate widely but trace to small, non-blinded reports rather than to RCTs indexed in MEDLINE; readers can confirm the absence of registered trials directly on ClinicalTrials.gov, and treat such claims as unproven (grade D).

What doses appear in the literature?

Reported strictly as information, not a protocol. The primary rodent geroprotection source used Vilon at 0.1 micrograms subcutaneously, once daily for five consecutive days each month, in female CBA mice from six months of age, continued long-term.4 Per kilogram this is a very low microgram dose, and it does not translate to a validated human dose. In-vitro IL-2 effects were concentration- and time-dependent in cell culture, with assay-dependent micromolar values that do not generalize to dosing.1 There is no validated human dose: vendor 'protocols' such as multi-milligram subcutaneous courses of reconstituted lyophilized powder are not derived from controlled human trials and reflect grey-market practice, not science.8 Because research-use-only material is not made to pharmaceutical standards, sterility, potency, and endotoxin content are not assured.8

How safe is Vilon?

Human safety data are absent in any formal sense. There is no MEDLINE-indexed human safety or adverse-event dataset, no toxicology dossier supporting human use, and no FDA review.8 In rodents, chronic low-dose subcutaneous Vilon produced no reported unfavorable developmental effects and did not alter free-radical processes or estrus function — described by the authors as supporting safety of chronic administration in that model — but animal tolerability is not human safety.4 The dominant real-world hazard is product quality: because Vilon is sold research-use-only, injectable preparations may lack sterility, stability, potency, and endotoxin testing and may be made in non-compliant facilities, making injection-site reactions and contamination the most plausible practical harms.8 Theoretically, effects on immune signaling (IL-2) and proliferation/chromatin pathways (PARP/SIRT1) cut both ways and warrant caution about immune dysregulation in active malignancy or autoimmune disease.7 Pregnancy and lactation should be excluded entirely.

What is the FDA and WADA status in 2026?

Vilon is not FDA-approved for any indication; it has no NDA or BLA, no USP monograph, and no GRAS status.8 Compoundable peptides must be FDA-approved, carry a USP monograph, or appear on the 503A bulks list (interim Category 1) — Vilon meets none of these, so it has no legal compounding pathway in the United States.8 The broader 2023-2026 FDA tightening of peptide compounding, including placement of numerous peptides into the restrictive Category 2 of the interim 503A bulks list and ongoing 2026 enforcement activity, reinforces that obscure bioregulators like Vilon sit outside the permitted space.9 It is sold as a lyophilized research-use-only chemical 'not for human use'; RUO peptides cannot legally be used in human or veterinary compounding, and the FDA has called RUO disclaimers on products sold with syringes 'a ruse.'8

For athletes the picture is one of unresolved risk rather than clearance. Vilon is not explicitly named on the current (2026) WADA Prohibited List.10 However, immune-modulating and growth-related peptides are an enforcement focus, and any non-approved peptide carries contamination and inadvertent-doping risk — drug-tested athletes should verify with their anti-doping authority and treat unverified peptides as high-risk.10

Bottom line. Vilon is a genuinely interesting mechanistic curiosity — an ultrashort Lys-Glu dipeptide proposed to act as a direct gene/chromatin-level regulator of immune (IL-2) and longevity (SIRT1/PARP) pathways. But it has been studied almost exclusively in mice and cell culture by one Russian group, with no human RCT, no independent replication, and no validated human pharmacokinetic or safety data. It is promising as a research hypothesis, unproven and not advisable for human use as of 2026. From a root-cause functional-medicine lens, immune aging is better addressed through validated upstream levers — thymic-supportive nutrition, infection burden, sleep, stress, and metabolic health — than an unvalidated peptide of uncertain provenance.