Cortagen

What it is

Cortagen is used by researchers and clinicians primarily in Russia to support nerve repair, brain recovery after restricted blood flow, and age-related cellular renewal. It works by helping brain and nerve cells reactivate genes that shut down with age or injury. No Western regulatory body has approved it as a drug, and human safety data remain limited.

The scientific side

Cortagen is described as a synthetic tetrapeptide (Ala-Glu-Asp-Pro) developed through directed synthesis from the amino acid sequence of Cortexin, a natural polypeptide complex extracted from bovine brain cortex. Its primary proposed mechanism is tissue-specific bioregulation: in organotypic culture experiments, Cortagen selectively stimulated proliferation of brain cortex explants but not explants from other tissues, demonstrating organ-targeted activity consistent with the cytogen hypothesis advanced by Khavinson and colleagues. At the molecular level, Cortagen modulates gene expression broadly. A cDNA microarray study in mouse heart identified 234 clones (1.53% of 15,247 transcripts) with significant expression changes after a 5-day injection course, with maximum upregulation of +5.42-fold and downregulation of -2.86-fold, revealing both shared and Cortagen-specific transcriptomic effects relative to Epithalon, Vilon, and melatonin. Cortagen also activates interleukin-2 mRNA synthesis in splenocytes in vitro in a concentration- and time-dependent manner, and modulates IL-2 gene expression in hypothalamic cells in vivo via both intramuscular and inhalation routes. Epigenetic effects have been documented in lymphocytes from individuals aged 75–88: Cortagen induces deheterochromatinization (decondensation) of facultative heterochromatin and activates ribosomal genes on acrocentric chromosome satellite stalks, reversing age-associated chromatin condensation without affecting pericentromeric structural heterochromatin. In antioxidant studies, injections reduced lipid peroxidation products and oxidative protein modification in rat serum and cerebral cortex. In ischemia models, Cortagen prevented excessive lipid peroxidation and preserved antioxidant defenses in brain tissue while accelerating behavioral recovery in rats with chronic cerebral ischemia. Peripheral nerve regeneration studies showed intramuscular Cortagen at 10 µg/kg for 10 days increased sciatic nerve fiber growth rate and conduction velocity by 27% and 40% respectively in transected rats.

Class: Synthetic tetrapeptide peptide bioregulator (Khavinson peptide; cytogen class)

What it's studied for

• Peripheral nerve regeneration and repair Animal studies only
  • Intramuscular Cortagen 10 µg/kg for 10 days after sciatic nerve transection and suturing in Wistar rats increased regenerating nerve fiber growth rate by 27% and conduction velocity by 40% compared to controls. PMID 11276314 Turchaninova LN et al. Bull Exp Biol Med. 2000 Dec;130(12):1172-4.
  • Demonstrated a delayed effect of Cortagen on functional restoration of injured peripheral nerve in rats, consistent with the nerve-regeneration properties reported in PMID 11276314. PMID 12134478 Kolosova LI et al. Dokl Biol Sci. 2002 May-Jun;384:183-4.
• Neuroprotection and recovery in chronic cerebral ischemia Animal studies only
  • Cortagen accelerated recovery of individual behavior in ischemic rats with both high and low hypoxia resistance, prevented excessive lipid peroxidation activation, and preserved antioxidant activity in brain tissue. Results suggested utility as a neuroprotective adjunct in chronic brain ischemia. PMID 21476278 Zarubina IV, Shabanov PD. Eksp Klin Farmakol. 2011;74(2):8-15.
• Age-related chromatin remodeling and epigenetic rejuvenation Human observational
  • In leukocytes from subjects aged 75–88 years, Cortagen along with other short peptides induced activation of ribosome genes, decondensation of condensed chromatin fibrils, and deheterochromatinization of age-condensed euchromatin regions. Effect on pericentromeric structural heterochromatin of chromosomes 1, 9, and 16 PMID 15085253 Khavinson VKh et al. Bull Exp Biol Med. 2004 Jan;137(1):78-81.
  • In lymphocytes from individuals aged 75–88, Cortagen (Ala-Glu-Asp-Pro) induced selective deheterochromatinization of facultative heterochromatin and activated ribosomal gene synthesis on acrocentric chromosome satellite stalks, while not deheterochromatinizing pericentromeric structural heterochromatin — a selective ep PMID 37042594 Lezhava T et al. Georgian Med News. 2023 Feb;(335):79-83.
• Antioxidant and free-radical modulation in brain tissue Animal studies only
  • Injections of Cortagen to Wistar rats decreased LPO (lipid peroxidation) product content and reduced oxidative modification of proteins in rat serum and cerebral cortex, alongside suppression of antioxidant enzyme activity. PMID 18239817 Kozina LS. Bull Exp Biol Med. 2007 Jun;143(6):744-6.
• Immunomodulation and cytokine gene expression Mechanistic only
  • Cortagen (Ala-Glu-Asp-Pro) activated IL-2 mRNA synthesis in mouse CBA splenocytes in vitro in the absence of specific inductors; effect was concentration- and duration-dependent and less pronounced than that of Vilon or Epithalon. PMID 12447482 Kazakova TB et al. Bull Exp Biol Med. 2002 Jun;133(6):614-6.
  • In situ hybridization in rat brain paraffin sections showed Cortagen modulated IL-2 gene expression in hypothalamic cells in vivo, with effects varying by administration route (intramuscular vs. inhalation) and time point. PMID 16224591 Kazakova TB et al. Bull Exp Biol Med. 2005 Jun;139(6):718-20.
  • Cortagen modulated lymphocyte-activating factor production by peritoneal macrophages; showed opposing effects in young vs. old mice and in resident vs. LPS-stimulated macrophages, suggesting age-dependent immunoregulatory effects. PMID 17426849 Gumen AV et al. Bull Exp Biol Med. 2006 Sep;142(3):360-2.
• Tissue-specific proliferation support (brain cortex explants) Mechanistic only
  • Cortagen selectively stimulated growth of rat brain cortex explants in organotypic culture without stimulating liver, thymus, or subcortical structure explants, confirming tissue-specific cytogen activity. PMID 11713572 Khavinson VK. Bull Exp Biol Med. 2001 Aug;132(2):807-8.
  • Tissue-specific effects of Cortagen confirmed in organ culture of rat tissues of various ages; effect dependent on applied peptide concentration. PMID 12096446 Khavinson VKh et al. Adv Gerontol. 2002;9:95-100.
• Cardiovascular gene expression modulation Mechanistic only
  • cDNA microarray analysis of 15,247 transcripts in CBA mouse heart after 5-day Cortagen injection course identified 234 clones (1.53%) with significant expression changes; maximum up-regulation +5.42-fold, down-regulation -2.86-fold. Cortagen effects showed both overlap with and divergence from Vilon, Epitalon, and mela PMID 15159690 Anisimov SV et al. Neuro Endocrinol Lett. 2004 Feb-Apr;25(1-2):87-93.
• Thymocyte signaling and immune activation Mechanistic only
  • Cortagen did not produce comitogenic effects on thymocyte proliferation or modulate IL-1b comitogenic activity, and produced a less pronounced stimulatory effect on sphingomyelinase activity in thymocyte membranes than Vilon or Epithalon, suggesting a weaker role in T-cell sphingomyelin signaling. PMID 12420072 Khavinson VKh et al. Bull Exp Biol Med. 2002 May;133(5):497-9.

Safety signals

• Suppression of serum and cerebral cortex antioxidant enzyme activity (glutathione peroxidase, superoxide dismutase) observed alongside reduction of LPO products and oxidative protein modification in rats. Net immunological and redox implications in humans are not established. PMID 18239817
• No human safety or adverse event data identified in the 13 indexed abstracts. All controlled dose-response studies were conducted in rodents. Human reports of therapeutic use (peripheral nerve, cerebrovascular) lack quantified safety data in the reviewed abstracts. PMID 15159690

Contraindications

• No contraindications explicitly stated in any reviewed abstract. The absence of human safety data means standard peptide injection precautions apply (allergy to components, active infection at injection site, pregnancy/lactation — none formally studied). PMID 15159690

Community-reported dosing

All studies (13)

• PMID 15085253 Human observational
  Age-related chromatin remodeling and epigenetic rejuvenation
• PMID 37042594 Human observational
  Age-related chromatin remodeling and epigenetic rejuvenation
• PMID 11276314 Animal studies only
  Peripheral nerve regeneration and repair
• PMID 11713572 Mechanistic only
  Tissue-specific proliferation support (brain cortex explants)
• PMID 12096446 Mechanistic only
  Tissue-specific proliferation support (brain cortex explants)
• PMID 12134478 Animal studies only
  Peripheral nerve regeneration and repair
• PMID 12420072 Mechanistic only
  Thymocyte signaling and immune activation
• PMID 12447482 Mechanistic only
  Immunomodulation and cytokine gene expression
• PMID 15159690 Mechanistic only
  Cardiovascular gene expression modulation
• PMID 16224591 Mechanistic only
  Immunomodulation and cytokine gene expression
• PMID 17426849 Mechanistic only
  Immunomodulation and cytokine gene expression
• PMID 18239817 Animal studies only
  Antioxidant and free-radical modulation in brain tissue
• PMID 21476278 Animal studies only
  Neuroprotection and recovery in chronic cerebral ischemia