Cortagen

Cortagen (Ala-Glu-Asp-Pro, AEDP) is a synthetic tetrapeptide developed by Prof. Vladimir Khavinson and colleagues at the St. Petersburg Institute of Bioregulation and Gerontology, positioned as the cerebral-cortex-focused member of the institute's "cytogen" line of single-sequence synthetic bioregulator peptides. Cortagen is specifically the synthesized single-sequence counterpart of Cortexin, an older natural extract preparation derived from cattle cerebral cortex tissue that Russian clinicians have used since the 1980s — a similar cytomax-to-cytogen relationship documented for other Khavinson compounds in this catalog, such as Vilon's relationship to the natural extract Thymalin.

Chemically, Cortagen has molecular formula C17H26N4O9, molecular weight approximately 430.4 g/mol (independently cross-checked via manual atomic-mass calculation from the formula, which matched), CAS number 335591-03-2 (cross-confirmed via a specialty chemical supplier), PubChem CID 18439621.

At Verified Peptides, we think Cortagen has a genuinely more substantial and varied preclinical research base than several other Khavinson cytogens in this catalog, spanning peripheral nerve regeneration, cerebral ischemia, and systemic gene-expression studies, described in detail below — though, as with every other Khavinson-associated compound in this catalog, this research originates entirely from Russian, Khavinson-affiliated research groups.

Peripheral nerve regeneration, one of Cortagen's more concretely studied applications, is itself a well-established, independently significant area of neuroscience and clinical research: injuries to peripheral nerves (such as the sciatic nerve, the model used in Cortagen's key study) can result in prolonged or incomplete functional recovery even after surgical repair, and this general clinical problem has motivated substantial independent research into biological and pharmacological strategies to accelerate axon regrowth and remyelination — a legitimate scientific backdrop against which Cortagen's specific nerve-regeneration finding should be understood, even though that specific finding itself remains a single-institute result.

At Verified Peptides, we think Cortagen has one of the more methodologically varied preclinical evidence bases among the Khavinson cytogens in this catalog, spanning at least three genuinely distinct experimental models, and we want to describe this honestly alongside its real limitations. Beyond the nerve-regeneration and cerebral-ischemia studies described above, a 2004 study (Anisimov, Khavinson, and Anisimov, Neuro Endocrinol Lett, PMID 15159690) examined Cortagen's effects on gene expression in mouse heart tissue using microarray analysis of approximately 15,000 transcripts, reporting significant expression changes in 234 clones matching 110 known genes across various functional categories, with fold-changes ranging from 5.42-fold upregulation to 2.86-fold downregulation. We think it is worth noting directly that this is a somewhat unusual study for a compound whose primary research framing is cerebral-cortex-specific — testing a "brain cortex peptide" for effects on cardiac gene expression — which the original authors appear to have undertaken specifically to examine whether Cortagen's effects extend, or are limited to, its primary target tissue.

We want to be equally direct about this evidence base's real limitations: every study described above originates from Khavinson-affiliated Russian research groups, and we are not aware of any independent replication by researchers outside this network, nor any registered or published Western randomized controlled human clinical trial. Secondary sources describe reported human clinical use of Cortagen (and its natural-extract predecessor Cortexin) for nerve recovery and cerebrovascular parameters in Russian clinical settings, but we could not independently verify the specifics of these human studies against checkable, indexed primary sources with the same confidence as the animal studies cited above. We think it is worth directly comparing Cortagen's evidence profile to the other Khavinson cytogens built across this catalog: it is more substantively documented than Cardiogen and Crystagen (for which little to no dedicated research was located), roughly comparable in depth to Vilon, Chonluten, and Pinealon (each with a handful of specific, real studies), but still meaningfully behind genuinely independent, multi-group, internationally-published compounds such as Thymulin or Nesiritide. Researchers should calibrate their confidence in any specific Cortagen claim accordingly, weighing the real functional findings described above against the single-network origin of all of them.

No FDA, EMA, or other Western regulatory body has evaluated or approved Cortagen for any indication. At Verified Peptides, we sell research-grade Cortagen exclusively for laboratory research, and we think its combination of a specific, functionally-measured nerve-regeneration finding, a cerebral-ischemia behavioral study, and a genuinely distinct gene-expression investigation gives it a moderately more substantial (though still entirely single-network) evidence base than several other Khavinson cytogens built in this catalog.

Cortagen's relationship to Cortexin — the older natural bovine-brain-extract preparation it was synthesized to replicate in single-sequence form — mirrors a pattern seen elsewhere in this catalog's Khavinson-associated compounds (Vilon from Thymalin, Thymogen also from Thymalin), where a natural tissue extract used in earlier Russian clinical practice was later fractionated to identify and synthesize its proposed active peptide fragment as a standalone compound.

The 2011 chronic cerebral ischemia study's finding that Cortagen's effects were specifically studied across rats with "different resistance to hypoxia" reflects a genuinely more sophisticated experimental design than a simple treated-versus-untreated comparison, since it examined whether Cortagen's effects depended on the animals' baseline physiological resilience to oxygen deprivation — a nuance relevant to researchers interested in whether a compound's neuroprotective effects are uniform across different baseline vulnerability profiles.

The nerve-regeneration study's reported outcome measures — nerve fiber growth rate and conduction velocity — are both standard, independently established electrophysiological and histological measures used broadly in peripheral nerve injury research, not measures unique to Khavinson's research program, lending some methodological credibility to how that specific study's findings were measured even though the study itself was not independently replicated.

Cortagen's inclusion in a mouse cardiac gene-expression study, despite being developed and marketed as a brain-specific compound, illustrates a broader, honest point about tissue-selectivity claims across the Khavinson cytogen catalog: even compounds marketed around a specific target organ may show measurable effects in other tissues when directly tested, which is either evidence against strict tissue-selectivity or evidence of genuinely broader systemic activity, depending on interpretation — a nuance not always reflected in commercial marketing framing built around a single target organ.

At Verified Peptides, we require independent third-party HPLC purity testing and mass spectrometry identity confirmation for every batch of research-grade Cortagen we offer, with a Certificate of Analysis (COA) available for each lot. As a four-residue peptide, Cortagen is straightforward to synthesize to high purity using standard solid-phase peptide synthesis methods.

We source exclusively from manufacturers operating under Good Manufacturing Practice (GMP)-aligned quality systems, and every lot is independently verified rather than accepted solely on a supplier's internal documentation. Researchers should always request and review the specific COA for the lot they receive, confirming purity percentage and molecular identity before use in any experimental protocol.

Lyophilized Cortagen is stable when stored at -20°C, protected from light and moisture, and researchers can generally expect the unreconstituted peptide to maintain integrity over an extended period under these conditions. At Verified Peptides, we ship lyophilized peptide with appropriate cold-chain packaging to preserve stability in transit.

Once reconstituted with bacteriostatic water or another appropriate sterile diluent, Cortagen solution should be stored refrigerated at 2–8°C and used within the timeframe indicated on the product's documentation. As with other short peptides in this catalog, reconstituted solutions are generally less stable than the lyophilized form and more susceptible to degradation and microbial contamination with repeated freeze-thaw cycling.

Researchers should avoid repeated freeze-thaw cycles of reconstituted material and should follow the specific storage guidance provided with each lot's documentation to preserve sample validity for research use.