Cerluten

A peptide complex extracted from calf cerebral cortex and sold as oral capsules in the Khavinson bioregulator line, distinct from the defined synthetic bioregulator peptides and without any published study naming the product itself.

Also referenced as: Cerluten A-5, Cytomax Cerluten, Cytomax A-5, A-5 peptide bioregulator

Also appears in: Cognitive

What is Cerluten?

Cerluten is a low-molecular-weight peptide fraction extracted from the cerebral cortex of young calves, sold as oral capsules under the product code A-5 in the natural-extract branch of Vladimir Khavinson’s bioregulator line. It is peptide material, but it is not a peptide in the sense the rest of this catalog uses the word: it is an undefined mixture of short peptides and free amino acids, with no sequence, no molecular formula, and no single active constituent.

That distinction matters for how the compound is read. Khavinson’s program has two chemically separate branches — natural tissue extracts (historically called cytomedins, and cytamines in their oral form) and defined synthetic peptides (cytogens) built from the amino acid analysis of those extracts. PeptideBenchmark carries both, and the branch a product belongs to determines what can be verified about it. The synthetic entries — Pinealon (Glu-Asp-Arg), Vesugen (Lys-Glu-Asp), Vilon (Lys-Glu), Livagen (Lys-Glu-Asp-Ala), Cardiogen (Ala-Glu-Asp-Arg), Epitalon (Ala-Glu-Asp-Gly) and their relatives — are single molecules that can be synthesized to a specification and assayed against it. Cerluten sits on the extract side, alongside Endoluten (A-8, bovine pineal) and Vladonix (A-6, calf thymus), and it reaches the research-compound market largely because vendors shelve both branches together under one “bioregulator” heading.

How it works

No published mechanistic study has tested Cerluten as a product. The mechanism attributed to it is the general Khavinson bioregulation model, developed on other tissue complexes and on the synthetic peptides derived from them:

• Tissue-specific action, demonstrated with the synthetic peptides — the synthetic cytogens Cortagen, Epithalon, Livagen, and Vilon stimulated the growth of explants from rat brain cortex, subcortical structures, liver, and thymus respectively, in organotypic culture; each stimulated the tissue whose natural peptide complex had supplied the amino acid analysis for its synthesis, which is the group’s central argument that these preparations act on their source tissue rather than systemically (Khavinson, Bulletin of Experimental Biology and Medicine, 2001, 132(2):807–808)
• Extract-to-single-peptide bridge, established in the pineal gland — mass spectrometry and HPLC of the pineal polypeptide complex resolved it into free amino acids (3.26%), di- (23.19%), tri- (50.72%), tetra- (22.10%), and pentapeptides (0.72%), with AEDG detected among the tetrapeptides; the authors concluded the complex’s effects are determined by that component (Khavinson et al., Bulletin of Experimental Biology and Medicine, 2017, 164(1):41–43). No equivalent compositional analysis of the cortical complex has been published, so the analogous claim for Cerluten is an extrapolation from a different organ
• The cortical synthetic counterpart — Cortagen (Ala-Glu-Asp-Pro) was obtained by directed synthesis from the amino acid analysis of Cortexin, the natural brain cortex preparation; microarray of 15,247 transcripts in the hearts of female CBA mice after five consecutive days of Cortagen found 234 clones with significant expression changes, mapping to 110 known genes (Anisimov et al., Neuro Endocrinol Lett, 2004, 25(1-2):87–93). Note the readout tissue was heart, not brain
• Neuroprotection data sits with the synthetic peptides, not the extracts — in primary mouse hippocampal neurons under amyloid synaptotoxicity, the tripeptide EDR (200 ng/mL) — sold as Pinealon — increased mushroom spine counts by 71% and returned them to normal, while KED — sold as Vesugen — produced a smaller 20% effect (Kraskovskaya et al., Bulletin of Experimental Biology and Medicine, 2017, 163(4):550–553)

Each of these results belongs to a defined synthetic peptide or to a different organ’s extract. None of them establishes what an oral calf cortex extract does. All four are also authored by Khavinson or his immediate collaborators, so they describe the program’s own model rather than an outside test of it.

Research status

Nothing is indexed under the product name. A PubMed search for “Cerluten” returns zero records, and ClinicalTrials.gov holds no registration for Cerluten, for Cortexin, or for “peptide bioregulator” as of August 2026. There are no published pharmacokinetic data, no bioavailability data for the oral route, and no controlled human trial of this product.

The nearest evidence belongs to Cortexin, a cattle cerebral cortex polypeptide complex registered as a drug in Russia and administered by injection. It is the same chemical class as Cerluten — an undefined cattle-brain peptide mixture — and it is the only member of that class with controlled trial data.

• Aliferova et al. (2014) ran a multicenter, prospective, double-blind, placebo-controlled trial of low-dose Cortexin (10 mg intramuscularly three times daily) in 272 patients with acute ischemic stroke across three arms — two courses, one course followed by placebo, or two courses of placebo — over 70 days, and reported efficacy and safety favoring the two-course group, supported by a pharmacoeconomic analysis (Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 114(4):41–46)
• The Cochrane review of the class incorporated that trial and reached a negative conclusion. Ziganshina et al. (2023) pooled seven randomized trials totaling 1,773 participants; this update added the 272-participant Cortexin trial above to what had previously been a Cerebrolysin-only evidence base. Cerebrolysin or Cortexin probably result in little to no difference in all-cause death (RR 0.96, 95% CI 0.65–1.41; six trials, 1,689 participants; moderate-certainty evidence) — the one pooled estimate that explicitly includes Cortexin. No included study reported poor functional outcome, early death, quality of life, or time to restoration of capacity for work at all. Cochrane judged the Cortexin trial at low risk of bias for incomplete outcome data and unclear risk for every other domain (Cochrane Database of Systematic Reviews, 10:CD007026)
• The review’s harm signal belongs to Cerebrolysin specifically, not to the cattle-derived member. It found a probable increase in non-fatal serious adverse events (RR 2.39, 95% CI 1.10–5.23; three trials, 1,335 participants; moderate-certainty evidence), more pronounced in the subgroup dosed 30 mL for 10 days (RR 2.87; two trials, 1,189 participants). Those analyses and that millilitre-based dosing subgroup cover Cerebrolysin. One wording caution: the review’s concluding sentence describes the pooled agents as “derived from cattle brain,” while its own background section defines Cerebrolysin as porcine-derived — Cortexin is the cattle-derived member of the pool
• The animal comparison did not reproduce a Cortexin effect. Zhang, Chopp et al. (2019) at Henry Ford Hospital ran a prospective, randomized, blinded, placebo-controlled comparison of four brain peptide preparations in a rat embolic middle cerebral artery occlusion model. Cortexin produced functional outcomes indistinguishable from saline, and no preparation — including Cerebrolysin — reduced lesion volume; only Cerebrolysin separated from saline on neurological outcome (Journal of the Neurological Sciences, 398:22–26). This is a rodent study with different endpoints, so it does not directly refute the human trial, and it was funded by EVER Pharma, which manufactures Cerebrolysin — the reference comparator and the only agent that came out ahead. The sponsorship gives no incentive to understate a competitor’s null result, but the Cerebrolysin-favourable half of the finding should be read with it in view

The replication problem is structural. The clinical case for the bioregulator family is summarized by its own developers — Khavinson, Kuznik, and Ryzhak (2013) reviewed their own long-term studies of Thymalin, Thymogen, Vilon, Epithalamin, Prostatilen, Cortexin, and Retinalamin (Advances in Gerontology, 26(1):20–37) — and is published predominantly in Russian-language journals by the institute that developed and commercialized the preparations. Sponsor involvement runs through the wider class as well: Cochrane recorded that the manufacturer of Cerebrolysin supported three of the multicentre studies it reviewed, wholly or by supplying drug, placebo, randomisation codes, grants, or statisticians. Where an outside group has tested a member of this class under blinding, the effect has not reproduced.

Common dosage forms

• Oral capsules — the standard and essentially only retail format for the natural-extract line, containing a low-milligram quantity of total peptide complex per capsule. Oral delivery is unusual in the research-peptide market, where most compounds are lyophilized powders for reconstitution
• Labeled milligrams describe total extract, not an active — because the material has no defined constituent, a stated milligram figure refers to the mass of the fraction. There is no United States Pharmacopeia monograph, reference standard, or assay against which a lot can be verified
• Not the same as the injectable preparation — Cortexin, the pharmaceutical cattle-cortex complex used in the trials above, is a lyophilized powder for intramuscular injection registered in Russia. It is not an FDA-approved drug and is not the product sold as Cerluten
• The synthetic counterparts ship differently — Pinealon, Vesugen, and Cardiogen are sold as lyophilized powder in vials and as capsules, and unlike an extract they can be assayed for identity and purity against a stated sequence

Key considerations

• It is not a defined molecule, and that limits verification. A certificate of analysis for a synthetic peptide establishes identity, sequence, and purity against a specification. For a tissue extract there is no specification to test against, so a COA can characterize a lot but cannot establish that two lots are the same substance. Purity percentages quoted for extract products do not carry the meaning they carry for a synthetic peptide
• Do not import the synthetic data onto the extract. Cerluten is chemically distinct from Cortagen, Pinealon, and Epitalon. The organotypic culture, gene-expression, and neuronal-spine results that anchor discussion of this family were generated with defined synthetic peptides; treating them as evidence for a calf cortex extract conflates two branches of the program that Khavinson’s own work treats as separate
• The independent record for the class is negative. Cochrane found probably no mortality benefit for Cerebrolysin or Cortexin in acute ischemic stroke, and none of the pooled trials reported functional outcome, quality of life, or return to work at all. The review’s non-fatal serious adverse event signal attaches to Cerebrolysin rather than to the cattle-derived preparation, so it should not be quoted as a harm finding for Cortexin or for Cerluten. What the class does have is an absence of demonstrated benefit under independent scrutiny, from injectable pharmaceutical dosing that in any case does not transfer directly to oral capsules
• Bovine tissue sourcing carries a regulatory dimension. FDA rules bar human food from being manufactured from, processed with, or otherwise containing “prohibited cattle materials,” a category whose main component is specified risk material — defined to include the brain of cattle 30 months of age and older — and importers of record must affirm compliance at entry and produce supporting records on request (21 CFR 189.5). Calf-sourced material falls below that age threshold, so compliance turns on documented animal age and provenance rather than on tissue type alone, and the rule reaches products only insofar as they are marketed as human food. The prion and infectious-agent screening claims for these preparations trace to the developers themselves (Ryzhak et al., Bulletin of Experimental Biology and Medicine, 2003, 135(1):52–54) rather than to an independent assessment
• The naming is easy to get wrong. Cerluten (calf cortex extract, oral capsules), Cortexin (cattle cortex extract, injectable, Russian drug registration), Cerebrolysin (porcine brain extract, injectable), and Cortagen (Ala-Glu-Asp-Pro, defined synthetic tetrapeptide) are four different products routinely discussed as one. The “A-5” designation is a vendor product code within the extract line — the same scheme that numbers Vladonix A-6 and Endoluten A-8 — not a chemical identifier, and it does not appear anywhere in the scientific literature