Khavinson Peptide Bioregulators: The Complete Research Guide (Vilon, Epitalon, Thymalin, Pinealon, Cortagen, Cardiogen and more)

Peptide bioregulators are very short peptides — two to four amino acids — developed largely in St Petersburg under Professor Vladimir Khavinson and studied as tissue-specific regulators of gene expression. This guide maps the whole Khavinson family, gives the sequence of every bioregulator GenoPept stocks, explains the cytomax versus cytogen distinction, and gives an unvarnished assessment of an evidence base that is far thinner than its popular reputation suggests. Research context only.

Updated 10 September 2026~14 min readReviewed by the GenoPept technical team

What are peptide bioregulators?

Peptide bioregulators are ultra-short peptides — usually two to four residues — proposed to act as tissue-specific regulators of gene transcription rather than as receptor ligands. The concept and most of the primary literature come from the St Petersburg Institute of Bioregulation and Gerontology, where Vladimir Khavinson’s group has worked on them since the 1970s.

The programme began with organ extracts. Investigators fractionated peptide material from calf thymus, pineal gland, cortex, prostate and other tissues and reported tissue-selective biological activity. Over the following decades they identified candidate short sequences within those fractions and synthesised them as defined peptides.

The result is a catalogue of named compounds — Vilon, Epitalon, Pinealon, Cortagen, Cardiogen, Vesugen, Pancragen and others — each built from the same small alphabet of residues, dominated by lysine, glutamate, aspartate and one variable residue that the developers associate with tissue selectivity.

These are not conventional signalling peptides. They have no known cell-surface receptor, no established pharmacokinetic profile in the peer-reviewed literature, and their proposed mechanism sits outside standard receptor pharmacology. That makes them scientifically interesting and, equally, hard to evaluate.

Cytomaxes vs cytogens: two different kinds of product

Cytomaxes are natural peptide extracts from animal organs; cytogens are chemically defined synthetic short peptides. Conflating the two is the single most common error in writing about this family. A study on a cytomax is not evidence about a cytogen, even when the two are marketed as counterparts.

Thymalin is a cytomax: a polypeptide complex isolated from calf thymus, not a single defined molecule. Epithalamin, the pineal extract, is another. Both are mixtures whose exact composition varies with the preparation.

Epitalon (Ala-Glu-Asp-Gly) is a cytogen: one synthetic tetrapeptide, one CAS number, one molecular weight, verifiable by HPLC and mass spectrometry. So are Vilon, Pinealon, Cortagen and every other named short peptide in the table below.

This distinction has real consequences for citation. The best-known human-cohort publication in this field — Khavinson and Morozov’s 2003 report following 266 older participants over six to eight years and describing reduced mortality — used Thymalin and Epithalamin, the extracts. It is routinely cited as though it were evidence for the synthetic tetrapeptides. It is not.

The proposed mechanism: short peptides and gene expression

The unifying claim of the bioregulator field is that peptides of two to four residues can cross the cell and nuclear membranes and bind directly to regulatory DNA sequences, changing which genes a tissue transcribes. The Khavinson group set this out most fully in a 2021 systematic review in Molecules.

That review catalogues specific peptide–gene associations, and it is the most useful single entry point to the primary literature. Examples it lists include Pancragen (Lys-Glu-Asp-Trp) and pancreatic endocrine differentiation genes PDX1, NGN3 and PAX6; Vesugen (Lys-Glu-Asp) and senescence markers p16 and p21; Bronchogen (Ala-Glu-Asp-Leu) and bronchial epithelial genes including MUC family members and SFTPA1; and Pinealon (Glu-Asp-Arg) and Fkbp1b in neurons.

Why the model is contested

Three problems recur. First, direct sequence-specific binding of a dipeptide or tetrapeptide to double-stranded DNA is chemically demanding — such a short ligand has limited surface with which to read a base sequence. Second, most of the supporting biophysics comes from the same network that proposed the model. Third, cellular uptake and nuclear delivery of small, highly charged peptides is not straightforward and is rarely quantified in these papers.

None of that makes the observations wrong. It does mean the mechanism should be described as a working hypothesis, and effects should be reported as observed changes in gene expression rather than as demonstrated direct DNA binding.

Every Khavinson bioregulator in the store, with sequences

All sixteen bioregulators stocked are listed below with their one-letter and three-letter sequences, the tissue each is associated with in the literature, and a direct product link. Fourteen are defined synthetic short peptides; Thymalin is an extract, and Epitalon has its own dedicated guide.

Which bioregulator maps to which tissue

The organising idea of the family is one peptide per tissue: each bioregulator is named for, and studied in, a particular organ system. Grouping them by system is the fastest way to navigate the catalogue and to see where several compounds overlap.

Two patterns are worth noticing. Nearly every sequence is built from Lys, Glu and Asp plus one variable residue — Trp in Pancragen, Leu in Bronchogen and Ovagen, Pro in Cortagen, Crystagen and Prostamax. And several systems have more than one assigned peptide, which is why comparative work within a system is more informative than comparing across systems.

How good is the evidence, really?

The bioregulator literature is broad but shallow: many publications, mostly small, mostly from one research network, mostly in Russian-language or low-circulation journals, and rarely replicated by independent laboratories. That is the fair summary, and it should be stated plainly whenever these compounds are cited.

The strongest indexed material is the gene-expression work. The 2021 Molecules systematic review compiles peptide-to-gene associations across the family and is peer-reviewed in an indexed journal — although it is authored by the group that developed the compounds.

Animal work is more mixed than its reputation suggests. Anisimov and Khavinson’s 2010 Biogerontology review reports that long-term treatment with some peptide preparations increased mean lifespan by 20–40% in rodents. But look at an individual study: the 2003 SHR mouse experiment with Epitalon found no change in mean lifespan, a 12.3% increase in maximum lifespan, roughly 17% fewer chromosome aberrations and a six-fold drop in leukaemia incidence with total tumour incidence unchanged. Aggregate review statements and individual primary results do not always line up.

A 2025 review of Epitalon in the International Journal of Molecular Sciences, written by authors outside the originating group, was broadly positive about the biological activity literature while stating that physico-chemical and structural investigation of the peptide remains quite limited and that the described mechanisms may not be the only ones operating.

Laboratory handling and solution preparation

Short bioregulator peptides are highly polar, dissolve readily in water, and are chemically simpler to handle than most research peptides — none of the common sequences contains methionine or cysteine, so oxidation is not the leading degradation route. The main practical risks are moisture ingress into the lyophilised cake and freeze-thaw damage to solutions.

1. Warm before opening. Bring the sealed vial to room temperature so moisture does not condense onto a cold cake.
2. Add diluent gently. Run sterile or bacteriostatic water down the inside wall of the vial; swirl until clear, never shake.
3. Confirm clarity. Bioregulator solutions should be clear and colourless with no particulates.
4. Aliquot single uses. Split the stock so no vial is thawed twice.
5. Record everything. Compound, sequence, batch, concentration, diluent and date on each aliquot.

These figures are a concentration reference for preparing laboratory solutions. Because bioregulators are supplied as salts, molar concentrations calculated from label mass are upper bounds; use net peptide content from the certificate of analysis where molarity matters. Fuller method detail is in the reconstitution guide.