Cortagen

Cortagen (Ala-Glu-Asp-Pro) is a synthetic four-amino-acid peptide assembled from the amino acid composition of Cortexin, a natural brain-cortex polypeptide complex ⁵. It belongs to the short-peptide bioregulator family associated with Vladimir Khavinson's research program, along with Epithalon, Livagen, and Vilon ².

The research record concentrates on three themes:

• Peripheral nerve repair: a rat sciatic nerve injury model and open human clinical reports describe improved posttraumatic recovery ¹.
• Brain protection in ischemia and aging: animal studies and Russian-language clinical reviews cover chronic cerebral ischemia and age-related cognitive-neurometabolic decline ¹².
• Age-related chromatin remodeling: in cultured lymphocytes from people aged 75-88, Cortagen unrolled condensed DNA and reactivated silenced ribosomal genes ⁶.

No randomized controlled trial has been published. Human evidence is limited to open clinical reports ⁵ and ex vivo cell studies ⁶, so confidence is moderate where animal findings are strong and lower where human outcome data are missing.

Cortagen's main action is epigenetic rather than receptor-based. Inside a cell, DNA is packed into chromatin; when regions are tightly condensed, called heterochromatin, the genes there are usually switched off. Aging is associated with more of this condensation, and Cortagen appears to reverse part of it ⁶.

In a human ex vivo study, lymphocytes from donors aged 75-88 were treated with Cortagen. The peptide unrolled age-condensed heterochromatin, activated ribosomal genes at nucleolar organizer regions, and released previously silenced genes ⁶. The effect was selective: Cortagen did not decondense the structural pericentromeric heterochromatin seen with Epithalon and Livagen ⁶. In a separate cytogenetic study, sister chromatid exchange increased in telomeric regions while decreasing in medial chromosome-arm regions ¹⁴.

Secondary mechanisms documented in the literature include:

• Antioxidant action: Cortagen lowered lipid-peroxidation products and oxidative protein modification in rat serum and cerebral cortex, although this was paralleled by suppressed endogenous antioxidant activity ⁹. It also prevented excessive lipid-peroxidation activation in a chronic ischemia model ¹².
• Neurotrophic and regenerative activity: the peptide stimulated growth of rat cerebral-cortex explants in culture ². In rats with transected sciatic nerves, 10 mcg/kg daily for 10 days raised regenerating-fiber growth rate by 27% and conduction velocity by 40% ¹.
• Immune gene modulation: Cortagen modulated IL-2 mRNA in mouse splenocytes and rat hypothalamic structures, but it was generally the weakest of the peptides tested ³. It produced no thymocyte proliferation or sphingomyelinase stimulation ⁴, and in birds it did not reverse immune or hemostatic disturbances that Epithalon normalized ¹⁰.
• Broad transcriptome changes: five daily injections in mice altered expression of 110 known cardiac genes ⁵.

Documented effects differ in their strength of evidence. Animal and ex vivo human findings are the strongest current anchors.

Peripheral nerve regeneration (animal, open human reports) In rats with sciatic nerve transection and suture, 10 mcg/kg intramuscularly daily for 10 days increased regenerating-fiber growth rate by 27% and nerve conduction velocity by 40% versus controls ¹. Functional recovery continued and emerged after the injection course had ended, a delayed pattern ¹⁷. The available literature also reports a pronounced therapeutic effect on structural and functional posttraumatic recovery of peripheral nerve tissue in human clinical use ⁵.

Brain ischemia and behavior (animal) In a rat model of chronic cerebral ischemia, Cortagen and Cortexin accelerated behavioral recovery and prevented excessive lipid-peroxidation activation along with loss of brain antioxidant activity ¹². Mouse studies also report modulation of locomotor activity and anxiety-related behavior ¹¹, and a Drosophila model showed therapeutic activity in heat-shock neurodegenerative conditions ¹⁸.

Age-related chromatin remodeling (human ex vivo) In cultured lymphocytes from donors aged 75-88, Cortagen decondensed age-compacted heterochromatin, activated ribosomal genes, and selectively modified sister chromatid exchange ⁶. This is the mechanistic signature, but it remains a surrogate endpoint without clinical outcome trials.

Oxidative stress (animal) Cortagen lowered lipid-peroxidation products and oxidative protein modification in rat serum and cerebral cortex. The same studies noted suppression of endogenous antioxidant activity, so the net long-term meaning is not fully resolved ⁹.

Immune signaling (mixed, generally weak) Cortagen activated IL-2 mRNA in mouse splenocytes without added inducers, but was the least potent of the three peptides tested ³. Macrophage effects were in opposite directions in young versus old mice ⁸. It had no comitogenic thymocyte effect ⁴, and a 40-day avian course did not correct immune, erythrocyte, or hemostatic disturbances ¹⁰.

Cardiac transcriptome (animal) A five-day course in mice changed expression of 110 known genes in heart tissue, with maximum changes of +5.42-fold and -2.86-fold ⁵.

Only one quantitatively dosed protocol appears in the published literature: 10 mcg/kg intramuscularly once daily for 10 days after sciatic nerve injury in rats ¹. Other published courses were shorter or longer but often did not report full dose details.

• Rat sciatic nerve model: 10 mcg/kg intramuscularly daily for 10 days produced the 27% growth-rate and 40% conduction-velocity improvements ¹.
• Mouse cardiac transcriptome: once-daily injections for 5 days altered 110 known cardiac genes ⁵.
• Chronic brain ischemia model: a treatment course with Cortagen normalized behavior, lipid peroxidation, and antioxidant status in rats ¹².
• Avian model: a 40-day course did not normalize erythrocyte, immune, or hemostatic parameters ¹⁰.
• Free-radical balance: injected Cortagen reduced lipid-peroxidation products and oxidative protein modification in rat serum and cortex ⁹.

Practitioner and community protocols are typically built around a 10-day course of 5-10 mg daily, given intramuscularly or intranasally, with courses repeated one to three times per year and usually spaced 3-6 months apart. Clinical reviews describe repeated treatment courses in elderly patients, but there is no published human dose-finding or randomized trial to anchor the dose ¹³. Benefits are expected to lag the course, consistent with the delayed nerve-function recovery in animal studies ¹⁷.

Cortagen is supplied as a lyophilized, or freeze-dried, powder for injection. The reconstitution guidance in the available literature uses bacteriostatic water containing 0.9% benzyl alcohol as the diluent. Because the peptide contains two acidic amino acid residues, it dissolves well at neutral pH, and a separate acid pre-dissolution step is not required.

Handling guidance from the available protocol literature:

• Inject the diluent slowly against the vial wall.
• Swirl gently to dissolve; do not shake.
• Unreconstituted powder can be stored at -20 °C for long-term stability, with refrigeration at 2-8 °C acceptable for shorter periods.
• Once reconstituted, refrigerate at 2-8 °C and do not freeze the solution, because repeated freeze-thaw cycles can promote aggregation and loss of activity.
• Use the reconstituted solution within about 30 days, and discard it if it becomes cloudy or precipitates.

No formal stability data for Cortagen appear in the published literature, so these storage windows follow standard practice for small lyophilized peptides. The calculator below converts vial contents and diluent volume into a research dose.

No formal pharmacokinetic or drug-drug interaction studies for Cortagen exist in the indexed literature. What is known comes from mechanistic experiments, so entries below are working hypotheses rather than established contraindications.

Drug classes and mechanistic basis

• Neurotrophic or nootropic agents: Cortexin, Cerebrolysin, citicoline, and Semax overlap with Cortagen's neuroprotective profile. Combined use is documented in Russian clinical literature, and Cortagen plus Cortexin accelerated behavioral recovery in a chronic ischemia model ¹².
• Antioxidants: Cortagen lowers lipid-peroxidation products and oxidative protein modification, but also suppresses endogenous antioxidant activity in animal studies ⁹. High-dose antioxidant co-use could reinforce that suppression, so research practice tends to cycle rather than stack indefinitely.
• Immunosuppressants: Cortagen's effects on IL-2 and macrophage activation are directionally variable across tissues and ages ³. The net immune effect in a treated organism is not predictable.
• Anticoagulants and antiplatelets: research in birds found no hemostatic changes from Cortagen, unlike Epithalon ¹⁰. No coagulation interaction is predicted.
• Epigenetic drugs such as HDAC inhibitors: Cortagen decondenses facultative heterochromatin ⁶, so overlap with other chromatin-remodeling agents is theoretically possible but unstudied.

Peptide combinations

• Cortexin: Cortagen's sequence was derived by amino-acid analysis of Cortexin ⁵, and the two have overlapping neural effects in animal models ¹².
• Epithalon: the two differ by a single terminal amino acid, yet their functional profiles diverge. Epithalon normalized immune and hemostatic parameters in an avian model where Cortagen did not ¹⁰.
• Semax and Pinealon: these are grouped with Cortagen as short-peptide neuroprotectives in reviews of elderly patients ¹³.
• Vilon: a stronger immunomodulator in the same family, sometimes used to cover Cortagen's weaker immune axis ³.
• BPC-157: a common community pairing for peripheral nerve injury, resting on Cortagen's animal nerve-regeneration data ¹.

Continuous administration is not the pattern in the available literature. Published courses lasted 5 days ⁵, 10 days ¹, or 40 days ¹⁰, while practitioner and community protocols use finite 10-day courses with months between them.

The cycling rationale follows from the mechanism. Cortagen decondenses age-condensed heterochromatin, a structural change proposed to persist after the peptide has cleared ⁶. Nerve-function recovery in the rat model continued and emerged after the injection course ended ¹⁷, so benefits do not require constant exposure. A five-day mouse course was enough to shift heart transcript expression ⁵. Longer off-periods may also allow endogenous antioxidant systems to re-equilibrate, because Cortagen treatment lowered oxidative damage while suppressing endogenous antioxidant activity in rats ⁹.

No tolerance, receptor desensitization, withdrawal, or rebound phenomenon is documented in the available evidence. Breaks are therefore based on mechanism and course-design convention, not on a demonstrated tolerance signal. Community and practitioner reports describe courses repeated one to three times per year, with non-response after a full course considered a reason to reassess rather than extend dosing.

Cortagen is most often discussed in combination protocols rather than as an isolated treatment in clinical reviews ¹³.

• With Cortexin: Cortagen's sequence was derived from Cortexin ⁵, and the two peptides restored behavior and antioxidant status in a chronic cerebral ischemia model ¹². This is the most closely related neuroprotective combination.
• With Epithalon: the single amino acid difference produces divergent activity. Epithalon normalized immune and hemostatic parameters in birds where Cortagen did not ¹⁰, while both show antioxidant activity ⁹. Research protocols pair them to cover different aging axes.
• With Semax or Pinealon: these are the same short-peptide neuroprotective class and are reviewed together for elderly patients ¹³.
• With Vilon: Vilon is a stronger IL-2 inducer ³, so it is the more common immune-axis companion while Cortagen addresses neural tissue.
• With BPC-157: the strongest rationale is peripheral nerve repair, since Cortagen's rat sciatic-nerve data show 27% faster growth and 40% faster conduction ¹. This pairing is a community protocol rather than a published combination study.
• With melatonin: mouse cardiac microarray work found both shared and Cortagen-specific gene targets versus melatonin ⁵, but no controlled combination data exist.

Cortagen has no FDA approval for any indication and is not scheduled under the DEA Controlled Substances Act. It is not found in EMA, MHRA, or TGA marketing registries. The main documented human-use setting is Russian-language clinical and research literature, including use in elderly and old-age patients for neuroprotection ¹³ and an open report of posttraumatic peripheral nerve recovery ⁵.

In the United States, Cortagen is unapproved and cannot lawfully be compounded for human use through 503A or 503B pharmacies because it is not on the 503A bulks list. Commercial sale with therapeutic claims would raise unapproved-new-drug concerns.

Cortagen is not named on the WADA Prohibited List, and no published WADA determination exists for the compound. Because there is no published determination, it cannot be stated that it falls under the S0 non-approved-substances category or is prohibited at all times. No athlete sanction specifically citing Cortagen is documented in the available literature.

No controlled human tolerability trial exists for Cortagen. In the published human data, which come from lymphocyte studies in people aged 75-88 ⁶ and clinical-use reviews in elderly patients ¹³, no adverse events are documented, but safety was not a formal outcome in those reports.

Reported reactions in community use The common reporting is local and transient: injection-site pain, redness, or bruising with intramuscular use, and occasional mild fatigue on injection days.

Documented effects with safety relevance

• Oxidative profile: Cortagen reduced oxidative damage markers in rat serum and cortex ⁹ and prevented excessive lipid-peroxidation activation in ischemia ¹². It also suppressed endogenous antioxidant activity, a bidirectional effect of unclear long-term significance ⁹.
• Immune signaling: IL-2 and macrophage effects are variable and weak ³. Directional shifts are possible, but clinically manifest immune changes are not documented in humans.
• Chromosomal markers: Cortagen increased sister chromatid exchange in telomeric heterochromatin ¹⁴. The investigators interpret this as a marker of decondensation and gene release, but sister chromatid exchange is also used as a genotoxicity signal in some assays; the distinction is unresolved.
• Cardiac transcriptome: a five-day mouse course altered expression of 110 cardiac genes ⁵. Arrhythmic or blood-pressure effects in humans are unstudied.
• Tissue growth: Cortagen stimulated cerebral-cortex explant growth in culture ². This is a theoretical caution only around active or occult central nervous system malignancy.

Practitioner-derived relative cautions include active malignancy, autoimmune disease, chromosome-fragility syndromes, pregnancy, and lactation. No overdose threshold, drug-interaction study, or long-term cumulative-safety data are available.