Cortagen Research

Cortagen is a synthetic tetrapeptide whose sequence is alanine, glutamic acid, aspartic acid, proline, written Ala-Glu-Asp-Pro or AEDP ^[1]. It belongs to a group of short peptides developed in Russia and marketed as peptide bioregulators. This page summarizes what has actually been published about Cortagen, and what has not.

Identity and naming

Despite the name, cortagen is not a brain cortex extract, but a single defined molecule made by chemical synthesis ^[1]. The US National Library of Medicine indexes it under the entry terms Ala-Glu-Asp-Pro and cortagen, and PubChem holds it as CID 18439621, molecular formula C17H26N4O9, CAS 335591-03-2 ^[15].

Cortexin is a different substance, the natural brain cortex peptide preparation from which cortagen was derived by directed synthesis after amino acid analysis ^[5]. Under its own name Cortexin carries a much larger literature, 217 indexed records against cortagen's 15 ^[12], and results published for one do not transfer to the other.

One further naming point matters for anyone checking sources: the originating group's own review spells the compound Korthagen, which is not usable as a literature search term ^[2].

One research group produced almost all of this literature

This is the single most important thing to understand about cortagen. Vladimir Khavinson and the St Petersburg Institute of Bioregulation and Gerontology discovered these peptides, hold patents covering them, and sell them commercially. The same people also produced nearly all of the published research.

The numbers are stark: a plain PubMed search for cortagen returned 15 records in August 2026 ^[12]. In an authorship analysis of the indexed cortagen literature, 11 of 13 records carried Khavinson or a long-term collaborator ^[12]. Much of it is Russian-language with English abstracts only, in journals with limited international readership. This is not an independent evidence base, and it should not be described as one.

Papers from the group also declare no conflict of interest, including one of the studies cited here, which states that "The authors declare no conflict of interest" ^[9]. Khavinson is meanwhile one of four named inventors on a granted US patent covering a sibling tetrapeptide, assigned to a company named for his own institute's clinic ^[16].

The clearest compound-specific animal result is a null

The cleanest experiment that isolates cortagen from its siblings reported that cortagen did nothing. In neonatally hypophysectomized chickens and in old birds, epitalon (Ala-Glu-Asp-Gly) given for 40 days eliminated the induced changes in erythrocytes, immunity and hemostasis. Cortagen (Ala-Glu-Asp-Pro), which differs only in the final residue, did not affect the parameters studied ^[3]. This is an animal study, published in Russian, by the group that develops these compounds.

A negative finding published by a party with a commercial interest is harder to dismiss than a positive one. It also rebuts the assumption that these peptides all behave alike, since a one-residue change abolished activity entirely in this model.

The rest of the animal and cell work

Two Russian researchers with no Khavinson co-authorship reported that cortexin and cortagen accelerated recovery of disturbed behavior in rats with chronic brain ischemia, and limited excessive lipid peroxidation ^[4]. That is the strongest cortagen work published outside the developing group, which is a statement about how little exists rather than about how good it is. It is an animal study, published in Russian, and the abstract reports no sample size and no statistics. Cortagen was also tested alongside cortexin rather than alone, so the design does not separate the two.

A microarray study profiled gene expression in mouse heart after cortagen, using a 15,247-transcript platform ^[5]. That is an animal profiling experiment: it shows the compound is biologically detectable, not that it produces a health outcome.

Two studies applied cortagen to lymphocytes and leukocytes taken from human donors aged 75 to 88, alongside other peptides in the family ^[6][7]. The reported effects on chromatin were selective, with each peptide acting on different chromosome regions, and pericentromeric structural heterochromatin was not decondensed ^[6]. The two papers disagree on that point, because in the earlier one three other peptides in the family did decondense pericentromeric chromatin, though cortagen was not among them ^[7]. These are cells in a dish, and treating them is not the same as treating a person, which is the most common misreading of this literature. The cytogenetic endpoints used in both papers have no established clinical meaning. A separate in vitro study compared three peptides for their effect on interleukin-2 messenger RNA, and cortagen was the weakest of the three ^[8].

What has not been studied

No lifespan or longevity study of cortagen exists in the indexed literature, and systematic searches by compound name and by the sequence term AEDP returned no survival curve ^[12].

No human clinical study of cortagen is retrievable in the indexed literature, and no clinical trial of it is registered on ClinicalTrials.gov ^[13]. The single registry hit is a nutrition study of an unrelated enteral product, which matches on keywords only ^[13]. One developer-authored paper states, in its introduction and without citing a study, that cortagen produced a pronounced therapeutic effect on posttraumatic recovery of peripheral nerve tissue in humans ^[5]. Nothing retrievable stands behind that sentence, which is why it cannot be counted as human evidence.

No pharmacokinetic data for cortagen has been published in the indexed literature, in humans or in animals ^[10]. Nothing is known about how much reaches the bloodstream, how long it persists, or where it goes.

Cortagen is a tetrapeptide, and the intestinal transporter that carries small peptides intact across the gut wall, PepT1, handles di- and tripeptides ^[11][14]. No carrier-mediated intestinal route is known for a tetrapeptide of this kind. That is a mechanistic constraint rather than an experiment, and other routes have not been ruled out. The only published argument to the contrary is a modeling paper from the developing group ^[9]. It docked 26 short peptides including AEDP against the transporters LAT1, LAT2 and PEPT1, and concluded that their binding sites were large enough to carry tetrapeptides. No transport assay was run, in that paper or in any other. Docking scores are modeled rather than measured, and they are not evidence of transport, binding affinity or effect.

How cortagen relates to its siblings

These compounds are nested sub-sequences of one another: cartalax (AED) is cortagen's N-terminal tripeptide, and crystagen (EDP) is cortagen without its leading alanine ^[2]. Epitalon (AEDG) shares the same AED core and differs only in the final residue ^[2][3].

No published basis exists on which to tell a reader what functionally distinguishes cortagen from a sibling differing by one residue, and the literature is silent on that question. The one experiment that compared cortagen directly against a sibling found epitalon active and cortagen inactive ^[3].

Longevity figures that circulate for "Khavinson peptides" generally belong to other substances, including crude bovine extracts, and none of that data is cortagen data.

Conclusion

What can be said about cortagen with confidence is narrow. It is a defined synthetic tetrapeptide with authoritative structure records, and it has been detected as biologically active in animal and cell experiments. The one clean comparison against a sibling found it inactive ^[3]. Everything else rests on a single commercially interested group, and there is no human trial, no pharmacokinetic data and no independent replication of a specific result.

Frequently Asked Questions

Has cortagen been tested in humans? No human clinical study of cortagen is retrievable in the indexed literature, and no clinical trial of it is registered on ClinicalTrials.gov ^[13]. One developer-authored paper asserts a human effect on nerve recovery, but it cites no study and nothing retrievable stands behind the claim ^[5]. Two studies applied cortagen to lymphocytes and leukocytes taken from elderly human donors ^[6][7], and those are cells in a dish, which is not the same as treating a person.

Is cortagen the same thing as Cortexin? No. Cortagen is a defined synthetic tetrapeptide, Ala-Glu-Asp-Pro ^[1], while Cortexin is the natural brain cortex preparation from which it was derived by directed synthesis ^[5]. Cortexin also carries a much larger literature under its own name, and evidence for one does not carry over to the other ^[12].

Has any independent group replicated the findings? Very little independent work exists: eleven of 13 indexed cortagen records carry Khavinson or a long-term collaborator, and the group that produced them also patents and sells these compounds ^[12]. The one clear exception is a rat brain-ischemia study by two researchers with no Khavinson co-authorship, and it is not a replication of anything ^[4].

What does the clearest cortagen-specific animal experiment show? It shows a null result: in hypophysectomized and old birds, epitalon eliminated the induced changes in erythrocytes, immunity and hemostasis, while cortagen did not affect the parameters studied ^[3]. That is an animal finding, and it was published by the developing group.

References

1. 1

   Khavinson VKh, et al. Bulletin of Experimental Biology and Medicine. 2002. PMID 12420072. (Synthetic peptides Vilon, Epithalon and Cortagen in mouse thymocytes; gives Cortagen = Ala-Glu-Asp-Pro, a synthetic peptide rather than an extract.)
2. 2

   Khavinson V, et al. International Journal of Molecular Sciences. 2022. PMID 35887081. (Family sequence table; spells the compound Korthagen; nested AED- and ED- series.)
3. 3

   Kuznik BI, et al. Advances in Gerontology (Uspekhi Gerontologii). 2008;21(3):372-381. PMID 19432169. (Russian. Epitalon active, cortagen null, in hypophysectomized chickens and old birds.)
4. 4

   Zarubina IV, Shabanov PD. Eksperimental'naia i Klinicheskaia Farmakologiia. 2011;74(2):8-15. PMID 21476278. (Russian. Cortexin and cortagen in rats with chronic brain ischemia; abstract reports no sample size and no statistics.)
5. 5

   Anisimov SV, Khavinson VKh, Anisimov VN. Neuro Endocrinology Letters. 2004;25(1-2):87-93. PMID 15159690. (Cortagen and gene expression in mouse heart, 15,247-transcript microarray. The introduction records that Cortagen was obtained by directed synthesis from amino acid analysis of the cortex preparation Cortexin, and asserts a human nerve-recovery effect without citing a study.)
6. 6

   Lezhava T, et al. Georgian Medical News. 2023;(335):79-83. PMID 37042594. (Epitalon, livagen, cortagen and vilon on lymphocyte cultures from donors aged 75 to 88; pericentromeric structural heterochromatin not decondensed.)
7. 7

   Khavinson VKh, Lezhava TA, Malinin VV. Bulletin of Experimental Biology and Medicine. 2004;137(1):78-81. PMID 15085253. (Short peptides including cortagen applied to leukocytes of subjects aged 75 to 88; epithalon, livagen and prostamax, but not cortagen, decondensed chromosome 1 pericentromeric chromatin.)
8. 8

   Kazakova TB, et al. Bulletin of Experimental Biology and Medicine. 2002. PMID 12447482. (In vitro comparison of vilon, epitalon and cortagen on interleukin-2 messenger RNA; cortagen the least pronounced of the three.)
9. 9

   Khavinson VK, et al. Biomolecules. 2023. PMID 36979488. (In silico molecular modeling and computer-assisted docking of 26 ultrashort peptides, AEDP among them, against the LAT1, LAT2 and PEPT1 transporters, benchmarked against all 8,400 possible di- and tripeptides. No transport assay. Carries the statement "The authors declare no conflict of interest".)
10. 10

    PubMed E-utilities pharmacokinetic absence searches, run 27 August 2026. (No pharmacokinetic study located for cortagen in humans or animals.)
11. 11

    Spanier B, Rohm F. Comprehensive Physiology. 2018;8:843-869. PMID 29687907. (PepT1/SLC15A1 substrate specificity.)
12. 12

    PubMed E-utilities record counts and authorship analysis, run 27 August 2026. (Cortagen bare-term count 15; Cortexin bare-term count 217; 11 of 13 analysed cortagen records in-network; no lifespan or longevity record for cortagen or AEDP.)
13. 13

    ClinicalTrials.gov API v2 registry query, run 27 August 2026. (No registered trial; the sole cortagen keyword hit is NCT06852014, an unrelated enteral nutrition study.)
14. 14

    Terada T. Current Topics in Membranes. 2012. DOI: 10.1016/B978-0-12-394316-3.00008-9. PMID 23177989. (Peptide transporter substrate specificity.)
15. 15

    NLM MeSH supplementary concept record C431545 and PubChem CID 18439621, both resolved 27 August 2026. (MeSH heading alanyl-glutamyl-aspartylprolyine, entry terms Ala-Glu-Asp-Pro and cortagen. PubChem name lookup on "cortagen" returns CID 18439621, C17H26N4O9, molecular weight 430.4, with 335591-03-2 among its synonyms.)
16. 16

    United States patent US6727227B1, granted 27 April 2004. (Tetrapeptide Ala-Glu-Asp-Gly, that is epitalon, not cortagen. Four named inventors including VKh Khavinson. Assignee is the Clinic of the Institute of Bioregulation and Gerontology LLC.)