Peptide bioregulators, often called Khavinson peptides or Russian bioregulators, are short peptides and animal-organ extracts developed by Vladimir Khavinson and colleagues at the St. Petersburg Institute of Bioregulation and Gerontology.[1][2] Each one is said to act on a specific organ, such as the thymus, pineal gland, liver or prostate. A few, like Thymalin and Thymogen, are registered medicines in Russia,[3][4] but none is FDA-approved, and almost all of the research comes from one network of labs.[5][6]
This hub explains what these peptides are, the theory behind them, what each one is claimed to do, how strong the evidence is and where they stand legally. For individual compounds, see our profiles of Epitalon, Pinealon, Vilon, Cartalax, Testagen and Thymalin. For the wider field, see our longevity and immune peptides hub the longevity peptide category, our comparison of Epitalon vs TA-65 and our evidence-graded guide to the best peptides for longevity.
What are peptide bioregulators?
The idea dates to the 1970s and 1980s, when Khavinson and Vladimir Morozov extracted mixtures of small proteins from calf and cattle organs. They called these extracts “cytomedins,” described them in the Soviet Military Medical Journal, and proposed that each organ makes its own signalling peptides that keep that organ working.[7][8] Later, the group analysed the extracts and made synthetic versions of 2 to 4 amino acids, many of them named after their target organ, such as Cardiogen (heart) or Pancragen (pancreas).[9][1]
There are two broad types:
- Natural extracts (cytomedins): mixtures of peptides purified from animal tissue. Examples are Thymalin (calf thymus),[3] Epithalamin (cattle pineal gland)[5] and Cortexin (cattle brain cortex).[10]
- Synthetic short peptides: defined sequences of 2 to 4 amino acids. Examples are Vilon (Lys-Glu, or KE), Thymogen (Glu-Trp, or EW) and Epitalon (Ala-Glu-Asp-Gly, or AEDG).[8] Several were designed from the amino-acid makeup of an extract; Cortagen, for instance, was built from an analysis of Cortexin.[11]
The two types are linked. Khavinson’s group reports that the dipeptides KE and EW are active components of Thymalin.[12] Even so, the extract and the synthetic peptide are different products, and results for one should not be assumed to apply to the other.[6]
How are they supposed to work?
Khavinson proposed that short peptides regulate gene expression: that they enter cells, reach the nucleus and bind to specific DNA sequences or histone proteins, switching particular genes on or off.[2][1] A study co-authored by Khavinson reported that labelled Epitalon, Pinealon and Testagen entered the nuclei of human cancer cells in a dish,[13] and computer docking models suggest these peptides could bind DNA and pass through cell-membrane transporters.[14][15]
Two cautions apply. First, much of this support comes from computer modelling and cell cultures, not from measurements inside the human body. Second, the “organ-specific” claim rests mostly on lab studies in which, for example, the pancreas peptide acted on pancreatic cells and the lung peptide on bronchial cells.[16][17] Whether a peptide taken by mouth or injection reaches a target organ in people in meaningful amounts has not been shown. An independent 2026 review of Epitalon found that its pharmacokinetic data, meaning how the body absorbs, distributes and clears it, remain inadequate.[6]
The Khavinson peptides at a glance
Sequences use one-letter amino-acid codes (A = alanine, D = aspartic acid, E = glutamic acid, G = glycine, K = lysine, L = leucine, P = proline, R = arginine, W = tryptophan). “Claimed target” is what the developers describe, not a proven effect.
| Name | Sequence or source | Claimed target | Evidence level | Our page |
|---|---|---|---|---|
| Thymalin | Calf thymus extract[3] | Immune system | Russian medicine; older Russian human studies[18] | Thymalin |
| Epithalamin | Cattle pineal extract[5] | Pineal gland, aging | Russian-led studies, not independently confirmed[5] | See Epitalon |
| Cortexin | Cattle brain cortex extract[10] | Brain | Russian medicine[10] | None |
| Thymogen | EW (Glu-Trp)[8] | Immune system | Russian medicine; Russian clinical studies[19] | None |
| Vilon | KE (Lys-Glu)[1] | Immune system (thymus)[1] | Mostly animal and cell studies[20] | Vilon |
| Epitalon | AEDG[1] | Pineal gland | Cell and animal; small human studies[6] | Epitalon |
| Pinealon | EDR[13] | Brain | Cell and rat; small Russian human studies[21] | Pinealon |
| Cartalax | AED[1] | Cartilage, skin[1] | Cell studies only[22] | Cartalax |
| Testagen | KEDG[13] | Male reproductive system[1] | Cell and DNA-binding studies only[13] | Testagen |
| Vesugen | KED[16] | Blood vessels[23] | Cell studies; one 32-person Russian study[21] | None |
| Cortagen | AEDP[11] | Brain, nerves | Mouse studies[11] | None |
| Bronchogen | AEDL[16] | Lungs, bronchi | Rat lung-damage model[24] | None |
| Chonluten | EDG[8] | Lungs | Cell studies only[8] | None |
| Cardiogen | AEDR[1] | Heart[1] | Animal and cell studies[23] | None |
| Prostamax | KEDP[25] | Prostate[17] | Lab studies of cells and tissue[17][25] | None |
| Livagen | KEDA[26] | Liver | Animal and cell studies[26] | None |
| Ovagen | EDL[1] | Kidney, liver[1] | Rat kidney-injury models[27] | None |
| Crystagen | Not published | Immune system (spleen)[28] | One lab study of aging spleen[28] | None |
| Pancragen | KEDW[16] | Pancreas | Monkeys; one small human study[29][30] | None |
| Vesilute | Not published | Not published | No PubMed-indexed studies found | None |
A few notes on the table:
- Bronchogen’s sequence is given as Ala-Glu-Asp-Leu in most of the group’s papers,[16][13] but one paper’s title lists it as Ala-Asp-Glu-Leu.[31]
- Crystagen and Vesilute: we could not find a published amino-acid sequence in any peer-reviewed source, and we found no indexed study of Vesilute at all. We do not repeat sequences from sellers.
- Cortexin is related to, but different from, Cerebrolysin, a pig-brain extract developed separately.
What the research shows
The group has published extensively since the 1970s, and its reviews describe effects in cells, insects, rodents, monkeys and people.[9][2] Highlights the group reports include:
- Lifespan in animals: long-term treatment with some peptide preparations increased average rodent lifespan by 20% to 40%.[9] Results vary by peptide: in one mouse study, Epitalon extended average survival by 5.3%, while Vilon was followed by more physical activity and fewer lung tumors.[20]
- Mortality in older adults: in 266 older people followed for 6 to 8 years, the group reported 2.0- to 2.1-fold lower mortality with Thymalin and 1.6- to 1.8-fold lower with Epithalamin, compared with a control group.[18]
- Blood sugar: in a Ukrainian study of older adults with type 2 diabetes, Pancragen lowered fasting glucose and insulin resistance.[30]
- Surgery: a Russian placebo-controlled trial reported fewer complications after abdominal cancer surgery in older patients given nasal Thymogen beforehand.[19]
- Lungs: in rats with chemically induced lung disease, Bronchogen reversed signs of airway damage.[24]
The group’s Russian-language reviews summarize clinical use of Thymalin, Thymogen, Vilon, Epithalamin, Cortexin and other preparations in people of different ages, with a focus on aging.[32]
How strong is the evidence?
Specific weaknesses to keep in mind:
- Limited replication. The clearest independent result so far is a 2025 UK cell study that found that Epitalon lengthened telomeres (the protective ends of chromosomes) in human cell lines: through the enzyme telomerase in normal cells, and mainly through a different mechanism, called ALT, in breast cancer cells.[33] A Russian rat study of Bronchogen came from a pulmonology institute without Khavinson as a listed author.[24] Most other compounds have no independent studies we could find.
- Extract vs synthetic confusion. Many claims about synthetic peptides rely on older studies of extracts, which are chemically different.[6]
- No long-term safety data. A 2026 review of peptides used for aging found that unapproved peptides lack long-term safety data and systematic validation.[34]
- Mechanism mostly modelled. The gene-regulation theory rests largely on cell studies and computer docking.[14][15]
For a deeper look at one compound, our Epitalon profile reviews the telomere and lifespan data in detail.
Medicines vs supplements: status in Russia
In Russia, these products fall into two groups:
- Registered medicines. Vidal, the Russian drug reference, lists Thymalin (thymus extract injection) for immune deficiency in adults and children,[3] Thymogen (alpha-glutamyl-tryptophan) for use alongside other treatment in viral and bacterial infections with weakened immunity,[4] and Cortexin (cattle brain cortex polypeptides) for conditions including impaired brain circulation.[10] Each has a current Russian registration certificate.
- Dietary supplements. Khavinson and co-authors have proposed short peptides, including those synthesized at the institute, for oral use as “biologically active food additives,” Russia’s term for dietary supplements.[35] The Russian drug reference RLS lists Cartalax (as Kartalax) and Testagen as dietary supplements rather than medicines.[42][43] The group has also described preparations called “Cytamins,” aimed at maintaining working capacity and longevity in military personnel.[36]
We could not confirm the Russian status of the other synthetic peptides in the table, so we do not list them as approved there. We also found no current Vidal entry for Epithalamin.
Are peptide bioregulators legal in the US?
- Not FDA-approved. We found no FDA approval for any product in this family.
- Compounding: Thymulin acetate (see below) sits in FDA’s category for substances nominated without adequate support.[37] Epitalon went before an FDA advisory committee in July 2026; see our Epitalon profile for the outcome.[38] None of the other names in our table appears on FDA’s 503A compounding lists as of May 14, 2026.[37]
- Sport: none of these peptides is named on the World Anti-Doping Agency’s 2026 Prohibited List. Category S0 bans, at all times, any pharmacological substance not covered elsewhere on the list that has no current approval by any government health authority for human therapeutic use.[39] WADA does not name these peptides, but in our reading S0 covers the unapproved synthetic peptides sold online, such as Vilon, Cartalax or Testagen. Thymalin, Thymogen and Cortexin are approved in Russia, so in our reading S0 may not apply to them; athletes should check with their anti-doping agency.
This is general information, not legal advice; rules differ by country and change over time.
A note on Thymulin
Thymulin is sometimes grouped with Khavinson peptides, but it is not one of them. It is a natural thymic hormone made by thymus epithelial cells and discovered in the early 1970s. It is a 9-amino-acid peptide that needs zinc to work and helps T cells mature.[40][41] Most research on it is in animals.[41] Despite the similar names, Thymulin is also different from Thymalin, the Russian thymus extract.
Side effects and safety
No large, independent safety studies exist for any of these peptides.[34][6] The developers’ papers generally report few adverse effects, but small studies cannot detect rare problems, and the Alzheimer’s Drug Discovery Foundation review noted that a well-conducted phase 1 safety study is still needed.[5] Extracts from animal organs raise added questions about purity and batch-to-batch consistency, since their safety depends heavily on the manufacturing process.[5]
If you are considering any of these products, talk with a doctor first, particularly if you have cancer, an autoimmune condition, or a weakened immune system, or if you are pregnant.
