Khavinson Peptide Bioregulators: Pinealon, Vilon, Thymalin & More

Khavinson peptide bioregulators are a family of very short peptides (two to four amino acids) and animal-tissue peptide extracts developed by Professor Vladimir Khavinson and colleagues at the St. Petersburg Institute of Bioregulation and Gerontology in Russia. Each is linked to a particular organ or tissue: Pinealon to the brain, Vilon and Thymalin to the thymus and immune system, Epitalon to the pineal gland, and Testagen to the male reproductive system. Their developers propose that these peptides act on gene expression in their target tissues. That idea is still a hypothesis. Most of the evidence comes from one research group, in small studies published mostly in Russian journals, and none of these peptides is FDA-approved.

This guide covers where bioregulators came from, how they are supposed to work, what has been published on each of the main compounds, and where they stand with U.S. regulators as of October 2026.

Educational content for licensed healthcare professionals. Not medical advice; dosing and treatment decisions belong to the prescribing clinician.

The Main Bioregulators at a Glance

Sequences are as reported in the peer-reviewed literature cited below. Products sold under these names are not standardized, so what is in a given vial or capsule may differ.

Who Is Vladimir Khavinson?

Vladimir Khavinson is a Russian gerontologist who has led the St. Petersburg Institute of Bioregulation and Gerontology. The bioregulator program started with peptide extracts from animal organs: Thymalin from the thymus, Epithalamin from the pineal gland, and Cortexin from the brain cortex. Researchers then analyzed the amino acids in those extracts and made short synthetic peptides "by directed synthesis based on amino acid analysis". That is how one of the group's own papers describes Cortagen, which was designed from Cortexin [5]. Epitalon was developed the same way from Epithalamin [10].

So the field has two generations of products. The first is a set of tissue extracts, which are complex, variable mixtures. The second is a set of synthetic di-, tri- and tetrapeptides, which are defined molecules. They should not be treated as the same thing. Epithalamin is not Epitalon, and Thymalin is not a single peptide.

The Proposed Mechanism: Short Peptides and Gene Expression

The central claim is that short peptides act as epigenetic signals. In a 2021 systematic review, Khavinson's group wrote that peptides of 2–7 amino acids "can penetrate into the nuclei and nucleoli of cells and interact with the nucleosome, the histone proteins, and both single- and double-stranded DNA", and that they may influence DNA methylation and gene expression [1].

Some laboratory evidence supports parts of this. In HeLa cells, fluorescently labeled Epitalon, Pinealon and Testagen were seen in the cytoplasm, nucleus and nucleolus. In cell-free experiments, the peptides changed the fluorescence of DNA fragments differently depending on the DNA sequence, which the authors read as sequence-specific binding [3].

Read this evidence carefully:

• It is mechanistic, not clinical. Showing that a peptide can enter a nucleus or bind a DNA fragment in vitro does not show that the amounts reaching the bloodstream produce a meaningful change in gene expression in a human organ.
• Much of the "gene targeting" work is computational. Recent papers use molecular docking and bioinformatics to predict which gene promoters a dipeptide might bind [7]. That kind of modeling generates hypotheses. It does not confirm them.
• Stability and delivery are open questions. Free di- and tripeptides are normally broken down quickly by peptidases. The group has modeled transport through amino-acid and peptide carriers, but that work is also computational.

Treat "bioregulators regulate gene expression" as the developers' working hypothesis, not as an established mechanism.

The Individual Bioregulators

Testagen (KEDG)

Testagen is the tetrapeptide Lys-Glu-Asp-Gly. In the indexed peer-reviewed literature it appears mainly in the nuclear-penetration and DNA-binding experiments described above [3]. We found no published human clinical trial of Testagen. Our Testagen overview and Testagen vs TRT comparison explain why it should not be treated as a substitute for testosterone therapy. Interest from women is covered in peptide bioregulators and women's hormone health.

Pinealon (EDR)

Pinealon (Glu-Asp-Arg) has the largest English-language literature of the synthetic bioregulators. In cell culture it limited reactive oxygen species and necrotic cell death under oxidative stress [4]. A 2020 review by the developers proposes that it acts on MAPK/ERK signaling, apoptosis proteins and antioxidant enzymes. The same review mentions improved memory in elderly patients, but that is a review statement, not a published controlled trial. A separate deep dive on Pinealon covers the research and safety record in more detail.

Vilon (KE)

Vilon is the dipeptide Lys-Glu, developed as a thymus-linked immunomodulator. Its studies are mainly in cell cultures and rodents, including a Russian-language study of chemically induced intestinal tumors in rats [9]. The KE dipeptide is also reported to be one of the active components of Thymalin [7].

Vesugen (KED)

Vesugen is described as a vasoprotective peptide. The developers report that it stimulated the proliferation marker Ki-67 in cultured vascular endothelial cells from aging animals, and they used molecular docking to model its binding to the promoter of the gene that encodes Ki-67 [8]. The paper refers to vasoprotective effects "revealed previously in elder people". We could not find those human data published as a controlled trial in an indexed journal.

Livagen (KEDA)

Livagen (Lys-Glu-Asp-Ala) is linked to the liver. A Russian-language review from the group summarizes animal models of liver fibrosis and hepatitis in which Livagen and a calf-liver polypeptide complex normalized immune and antioxidant markers [6]. There are no published human efficacy trials.

Cortagen (AEDP)

Cortagen (Ala-Glu-Asp-Pro) was designed from the brain-cortex extract Cortexin. A microarray study in mice found that a short course changed the expression of about 1.5% of the cardiac transcripts measured [5]. The same paper refers to nerve-recovery effects in humans, but we found no controlled human trial in the indexed literature.

Thymalin

Thymalin is different from the others: it is a polypeptide complex extracted from thymus tissue, not a synthetic short peptide. It has the longest clinical history of the group, including a long-term observational study in older adults [2] and non-randomized reports from Russian hospitals during COVID-19. It is often confused with thymosin alpha-1. They are different products, and a separate deep dive on Thymalin explains the difference.

Epitalon and Epithalamin

Epitalon (Ala-Glu-Asp-Gly) is the best-known bioregulator in the U.S. and the only one that has been through an FDA advisory review. An independent 2026 narrative review by U.S. clinicians concluded that Epitalon is "biologically active but clinically unproven". It found human evidence limited to small physiological or biomarker studies and an older controlled study in retinitis pigmentosa, and it found pharmacokinetic and long-term safety data inadequate [10]. See our Epitalon library page for detail.

How Strong Is the Evidence?

The honest summary is interesting but weak, for four reasons:

1. One research group. Most of the bioregulator literature comes from Khavinson's institute and its collaborators. Independent replication is limited. The 2026 Epitalon review specifically appraised "independent replication" and found it lacking [10].
2. Small studies. Human studies, where they exist, are small, often not randomized or blinded, and use surrogate endpoints.
3. Language and indexing. Many primary reports are in Russian-language journals, available in PubMed only as abstracts. That makes full critical appraisal hard for English-speaking prescribers.
4. Extract vs. peptide confusion. Results from extracts (Thymalin, Epithalamin) are often quoted as if they applied to synthetic peptides, and the other way around.

The most frequently cited human result shows these problems clearly. A 2003 paper reported that older adults given Thymalin and/or Epithalamin over 6–8 years had 1.6- to 4.1-fold lower mortality than controls [2]. The abstract does not describe randomization or blinding, and the result has not been independently replicated. A finding that large would need confirmation before it could inform practice.

Regulatory Status in the U.S. (October 2026)

• None of the bioregulators is FDA-approved for any indication.
• Epitalon is the only bioregulator voted on by FDA's Pharmacy Compounding Advisory Committee. At the July 23–24, 2026 meeting the committee voted 7–4 (1 abstention) to recommend adding Epitalon to the 503A Bulks List, against FDA staff's recommendation. The vote is advisory. Epitalon is not on the Bulks List until FDA completes notice-and-comment rulemaking, which is expected to run into 2027. See Epitalon and the 503A Bulks List.
• Testagen, Pinealon, Vilon, Vesugen, Livagen, Cortagen and Thymalin were not among the substances considered at the July 2026 PCAC. None is on the 503A Bulks List. In the U.S. they are most often offered as "research use only" chemicals or as imported oral products marketed like supplements. Neither channel involves FDA review of identity, purity, or effectiveness.

Status changes quickly. Check the FDA Peptide Status Tracker before relying on any of the above.

Safety Considerations

There are no systematic human safety data for most bioregulators. Practical concerns for prescribers:

• Unknown long-term effects. Agents proposed to alter gene expression or cell proliferation raise a theoretical concern in patients with active or recent cancer. This is the same question raised for Epitalon in our Epitalon side effects review.
• Product quality. Research-chemical and gray-market products have no assurance of identity, purity, sterility, or endotoxin limits.
• Extract-specific risks. Animal-tissue extracts such as Thymalin carry the general risks of biologic mixtures, including variable composition and the potential for immune reactions.
• Pregnancy, breastfeeding and pediatrics. No data.

Newtropin does not prescribe, compound, or dispense. We connect licensed providers with licensed 503A partner pharmacies covering all 50 states and D.C.; prescribers can start at For Providers.

Frequently Asked Questions

What are Khavinson peptides?

Khavinson peptides are short synthetic peptides and animal-tissue peptide extracts developed by Vladimir Khavinson's group in St. Petersburg. Each is linked to an organ, such as the brain (Pinealon), thymus (Vilon, Thymalin) or pineal gland (Epitalon). They are not FDA-approved.

Do peptide bioregulators really change gene expression?

That is their developers' hypothesis. Laboratory studies show some short peptides can enter cell nuclei and interact with DNA in vitro, and computer modeling predicts gene targets. It has not been shown that these effects occur at meaningful levels in humans or produce clinical benefit.

Is Testagen a bioregulator?

Yes. Testagen (Lys-Glu-Asp-Gly) is one of the synthetic Khavinson tetrapeptides, linked by its developers to the male reproductive system. No published human clinical trials were found in the indexed literature.

What is the difference between Epitalon and Epithalamin?

Epithalamin is a polypeptide extract of pineal gland tissue. Epitalon is a defined synthetic tetrapeptide (Ala-Glu-Asp-Gly) developed from Epithalamin's amino-acid composition. Results from one should not be applied to the other.

Are peptide bioregulators legal to prescribe in the U.S.?

None is FDA-approved, and none is on the 503A Bulks List. Epitalon received a 7–4 advisory recommendation in July 2026, but rulemaking is pending. The others have not been reviewed by the PCAC. Check the FDA Peptide Status Tracker for current status.

Why is most bioregulator research from Russia?

The field was developed at the St. Petersburg Institute of Bioregulation and Gerontology, and most studies come from that group and its collaborators. Independent replication outside that network is limited, which is the main weakness of the evidence base.

References

1. Khavinson VK, et al. Peptide Regulation of Gene Expression: A Systematic Review. Molecules. 2021;26(22):7053. PubMed
2. Khavinson VKh, Morozov VG. Peptides of pineal gland and thymus prolong human life. Neuro Endocrinol Lett. 2003;24(3-4):233-240. PubMed
3. Fedoreyeva LI, et al. 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;76(11):1210-1219. PubMed
4. Khavinson V, et al. Pinealon increases cell viability by suppression of free radical levels and activating proliferative processes. Rejuvenation Res. 2011;14(5):535-541. PubMed
5. Anisimov SV, et al. Elucidation of the effect of brain cortex tetrapeptide Cortagen on gene expression in mouse heart by microarray. Neuro Endocrinol Lett. 2004;25(1-2):87-93. PubMed
6. Kuznik BI, et al. The influence of polypeptide liver complex and tetrapeptide KEDA on organism physiological function in norm and age-related pathology [in Russian]. Adv Gerontol. 2020;33(1):159-164. PubMed
7. Linkova N, et al. 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;24(17):13377. PubMed
8. Khavinson VKh, et al. Epigenetic aspects of peptidergic regulation of vascular endothelial cell proliferation during aging [in Russian]. Adv Gerontol. 2014;27(1):108-114. PubMed
9. Pliss GB, et al. The effect of vilon (Lys-Glu) on 1,2-dimethylhydrazine-induced neoplasia [in Russian]. Vopr Onkol. 2005;51(4):466-469. PubMed
10. Jain A, et al. Epitalon and Epithalamin: A Narrative Review of Mechanistic, Preclinical, and Clinical Evidence. Int J Mol Sci. 2026;27(19):8922. PubMed