Cerebrolysin vs Selank.

Cerebrolysin is a peptide preparation produced by the enzymatic breakdown of purified porcine (pig) brain proteins, yielding a mixture of low-molecular-weight peptides and free amino acids. It is manufactured by EVER Neuro Pharma and given by injection or intravenous infusion rather than orally. Marketed as a neurotrophic and neuroprotective agent, it has been studied across acute ischaemic stroke, vascular dementia, Alzheimer's disease and traumatic brain injury. It is one of the most extensively trialed brain-peptide preparations, yet its clinical benefit remains genuinely contested.

Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, with the laboratory designation TP-7. It is a stabilized analog of tuftsin, an endogenous immunomodulatory tetrapeptide (Thr-Lys-Pro-Arg) derived from the Fc region of immunoglobulin G; the added Pro-Gly-Pro tail confers resistance to enzymatic degradation. It is studied primarily as an anxiolytic and nootropic agent and is most associated with Russian neuropharmacology research.

Because Cerebrolysin is a complex biological mixture rather than a single molecule, its mechanism is described as pleiotropic. The peptide fraction is proposed to mimic endogenous neurotrophic factors, supporting neuronal survival, synaptic plasticity and neurogenesis. Preclinical work also suggests reduced excitotoxicity, anti-apoptotic signaling and effects on amyloid processing. The precise active components and their targets in humans are not fully defined.

Selank's parent peptide tuftsin acts on immune cells, and Selank retains immunomodulatory activity while shifting toward neuromodulation. Proposed central mechanisms include modulation of monoamine systems (serotonin, dopamine, noradrenaline) and interaction with the GABAergic and enkephalin/opioid systems; Selank has been reported to inhibit enkephalin-degrading enzymes, prolonging the action of endogenous enkephalins. It has also been reported to influence expression of brain-derived neurotrophic factor (BDNF) and to alter cytokine balance (e.g., IL-6 and interferon-related signaling). These mechanisms are largely characterized in rodent and in vitro models rather than established in humans.

Cerebrolysin has been evaluated in numerous randomized controlled trials, and two Cochrane systematic reviews summarize the best available evidence. The 2023 Cochrane review of acute ischaemic stroke concluded that Cerebrolysin probably has little or no beneficial effect on death or clinical outcome, and it flagged a possible increase in non-fatal serious adverse events, rating certainty of evidence as low to moderate. The 2019 Cochrane review of vascular dementia found possible short-term benefits on cognition and global function but did not recommend routine use, citing small trials, short follow-up and high risk of bias. Several included trials were industry-sponsored, which further tempers confidence. Taken together, the clinical picture is mixed and unsettled rather than clearly positive. The underlying trial set has a distinctive geography: a large share of the randomized evidence originates from centers in Eastern Europe, the CIS, China and parts of Asia, often with the manufacturer as sponsor or provider of study drug, and a substantial portion of the earlier literature was published in languages other than English, which complicates independent appraisal. Trial durations are typically short, on the order of weeks of treatment with follow-up rarely extending to a year, and outcome scales differ between studies, which limits pooling. Later work has continued in narrower settings: a randomized pilot study of speech therapy combined with Cerebrolysin for nonfluent aphasia after acute ischaemic stroke was published in Stroke in 2025, and clinical reviews of neuroprotective and neuroregenerative agents after severe traumatic brain injury continue to describe the evidence as inconclusive. What remains unknown is central rather than peripheral: the active components of the mixture are not identified, so batch-to-batch consistency cannot be verified by potency assay against a defined molecule, and no biomarker predicts response. Even so, Cerebrolysin is the best-studied compound in the animal-tissue peptide category by a wide margin, since preparations such as cortexin, thymalin and vilon have no comparable body of randomized evidence and have never been assessed by Cochrane.

The great majority of Selank evidence is preclinical (rodent and in vitro), covering anxiolytic-like behavior, stress models, immune/cytokine modulation, and tissue effects under chronic stress (e.g., Bull Exp Biol Med studies on rat intestine and liver under restraint/foot-shock stress, and a cytokine study under 'social' stress). Human clinical data are limited and come almost entirely from Russian-language trials and registry approval rather than large, independently replicated, placebo-controlled studies indexed in Western literature; reported uses include generalized anxiety disorder and asthenic/neurasthenic conditions. A frequently cited molecular review (Protein and Peptide Letters, 2018, PMID 30255741) summarizes the proposed biology. Overall, robust, independently replicated human efficacy data are thin, and mechanistic plausibility should not be read as proven clinical benefit.

In trials Cerebrolysin was generally reported as well tolerated, with reactions such as dizziness, headache, agitation, sweating and injection-site effects. Cochrane reviewers noted a possible signal of increased non-fatal serious adverse events in the stroke setting, though this finding was uncertain, and that uncertainty is itself a finding: the trials were not individually powered for safety, adverse-event definitions varied between studies, and reporting completeness differed, so the signal can be neither confirmed nor dismissed from the existing data. As a porcine-derived biological given parenterally, allergic and hypersensitivity reactions are a theoretical concern, and product information in the countries where it is registered describes contraindications including known hypersensitivity, status epilepticus and severe renal impairment. Rapid infusion has been associated with transient reactions such as flushing, dizziness and palpitations. Because the preparation is a complex mixture rather than a single characterized molecule, immunogenicity and lot-to-lot variability are harder to evaluate than for a defined peptide drug. Material obtained outside licensed pharmacy channels adds contamination and counterfeit risk on top of the pharmacological questions, since parenteral products require verified sterility and endotoxin limits. Adequate monitoring in a trial setting includes supervised administration, observation for infusion reactions, renal function assessment, seizure history review and systematic adverse-event capture. It is a clinical product, not a dietary supplement, and any use is a medical decision.

Published reports, mostly from the developing Russian groups, describe Selank as generally well tolerated with a notably low sedation, dependence, and withdrawal profile compared with benzodiazepines, but rigorous long-term and large-sample safety data from independent groups are lacking. Because much of the safety record comes from the originating institutions and small studies, the true adverse-event and long-term safety profile in humans is not well established. As a peptide typically administered intranasally in research, purity, contamination, and product-quality concerns apply to non-pharmaceutical material. It has not undergone the comprehensive safety review required for major regulatory approval outside its country of origin.

Cerebrolysin is not approved by the US FDA and is not marketed in the United States. It is registered and used clinically in a number of countries across Europe, Asia, the CIS and Latin America. This entry is educational only and contains no dosing guidance.

Selank is reported to have been registered/approved in Russia (around 2009) for anxiety and asthenic conditions, marketed as an intranasal preparation. It is not approved by the US FDA and is not an approved drug in the EU; outside Russia it is effectively investigational and is widely sold as a research-use-only / not-for-human-consumption chemical. It is not a controlled substance and is not a standard WADA-prohibited agent, but its unapproved status means quality and legality vary by jurisdiction.