Semax vs Cerebrolysin: How They Differ
Semax is a single, defined seven-amino-acid peptide built from a fragment of ACTH, while Cerebrolysin is a mixture of small peptides prepared from pig brain. Both are studied in stroke and brain recovery, and both point to neurotrophic factors such as BDNF, but one is a known sequence you can write out and the other is a complex preparation defined by how it is made. Here is how they compare, what the human studies found, and what each suits as a research tool.
Findings
- Semax is a heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro, an analogue of the ACTH(4-10) fragment. In rats, a single intranasal application raised hippocampal BDNF protein 1.4-fold and BDNF messenger RNA 3-fold (2006).
- In 110 patients recovering from ischemic stroke, Semax raised plasma BDNF, which stayed high for the whole study, and sped recovery on the Barthel index (2018).
- Cerebrolysin is a porcine brain-derived peptide preparation with properties similar to the body’s own neurotrophic factors. In the 208-patient CARS trial, it produced a large improvement in arm function at day 90 against placebo (2016).
- A pooled analysis of six randomised trials in mild-to-moderate Alzheimer’s disease found Cerebrolysin better than placebo on global clinical change at 4 weeks and 6 months (2015).
What is Semax?
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its first four residues match positions 4 to 7 of adrenocorticotropic hormone (ACTH), followed by a Pro-Gly-Pro tail, and it is studied mainly by intranasal application, largely by Russian research groups. In rats, one intranasal application produced a maximal 1.4-fold rise in hippocampal BDNF protein, a 1.6-fold rise in phosphorylation of its receptor, trkB, and a 3-fold rise in BDNF exon III messenger RNA, and treated animals learned an avoidance task faster (Dolotov et al., Brain Res, 2006). A separate study found that intranasal Semax raised both BDNF and NGF gene expression in the rat hippocampus within an hour (Agapova et al., Neurosci Lett, 2007). The broader literature is covered in Semax peptide: what the research covers.
The ischemia research
In a rat model of stroke followed by restored blood flow, RNA sequencing found 394 genes expressed differently in Semax-treated brains than in saline-treated brains 24 hours later. Semax suppressed genes tied to inflammation and activated genes tied to neurotransmission, the reverse of the pattern ischemia produced on its own (Filippenkov et al., Genes, 2020).
The human work comes from one Moscow group. In 1997, 30 patients in the acute period of hemispheric ischemic stroke received Semax alongside standard care and were compared with 80 patients of similar severity on standard care alone; the Semax group showed faster recovery of general and focal deficits, especially motor ones, with EEG and evoked-potential monitoring (Gusev et al., Zh Nevrol Psikhiatr Im S S Korsakova, 1997). In 2018 the same group followed 110 patients through early or late rehabilitation after ischemic stroke. Semax raised plasma BDNF regardless of when rehabilitation began, the level stayed high throughout, and Semax with high BDNF sped and improved final recovery on the Barthel index of daily function (Gusev et al., Zh Nevrol Psikhiatr Im S S Korsakova, 2018). Both were comparisons against standard care rather than placebo-controlled trials. More detail is in Semax and stroke recovery: the BDNF research.
What is Cerebrolysin?
Cerebrolysin is a peptide preparation derived from porcine brain, given parenterally (by intravenous infusion in the stroke trials), with pharmacodynamic properties similar to those of the body’s own neurotrophic factors (Plosker and Gauthier, Drugs Aging, 2009). It is not one molecule. It is a mixture of peptides, and a 2024 analysis found that several preparations sold as similar to it had a significantly different peptide composition and lacked its neurotrophic activity in the laboratory (Seidl and Aigner, J Med Life, 2024). That is why its research record is tied to one manufactured product rather than to a sequence.
The stroke trials
The Cerebrolysin and Recovery After Stroke (CARS) trial randomised 208 patients, double-blind, to Cerebrolysin or saline once daily for 21 days, starting 24 to 72 hours after stroke, with all patients in a standardised rehabilitation programme. On the Action Research Arm Test at day 90, Cerebrolysin showed a large superiority over placebo (Mann-Whitney estimator 0.71), with a small-to-medium advantage across 12 global outcome scales and a dropout rate of 3.8% (Muresanu et al., Stroke, 2016). Pooling CARS-1 and CARS-2 (442 patients) confirmed the arm-function advantage at day 90 (Guekht et al., Neurol Sci, 2017).
The larger CASTA trial randomised 1,070 patients in Asia within 12 hours of stroke. Its primary combined endpoint was neutral, but among patients with severe strokes (NIHSS above 12), 90-day mortality was 10.5% with Cerebrolysin against 20.2% with placebo in a post hoc analysis (Heiss et al., Stroke, 2012). A 2023 Cochrane review of seven trials (1,773 participants) found little or no difference in all-cause death and more non-fatal serious adverse events (Ziganshina et al., Cochrane Database Syst Rev, 2023). The trials are summarised in Cerebrolysin: stroke and brain-injury research.
The dementia research
A meta-analysis of six randomised placebo-controlled trials in mild-to-moderate Alzheimer’s disease found Cerebrolysin significantly better than placebo on cognitive function at 4 weeks and on global clinical change at both 4 weeks and 6 months (Gauthier et al., Dement Geriatr Cogn Disord, 2015). An earlier review recorded dizziness or vertigo as the most frequently reported adverse event in the dementia trials (Plosker and Gauthier, Drugs Aging, 2009).
How do Semax and Cerebrolysin compare side by side?
| Question | Semax | Cerebrolysin |
|---|---|---|
| What is it? | Synthetic ACTH(4-10) analogue | Porcine brain-derived peptide preparation |
| Size | 7 amino acids, one defined sequence | Mixture of small peptides, no single sequence |
| Main research area | Stroke recovery, cognition, BDNF | Stroke recovery, dementia, brain injury |
| Mechanism focus | BDNF and trkB expression, gene regulation after ischemia | Neurotrophic-factor-like activity of the mixture |
| Human evidence | Russian stroke studies against standard care (1997, 2018) | Randomised placebo-controlled stroke and dementia trials |
| Usual research route | Intranasal | Intravenous infusion |
| Forms we supply | 10 mg vial, nasal spray | 60 mg vial |
Which one fits which research question?
- A single, known variable: Semax. Its sequence is fixed, so a result can be attributed to one molecule, and its BDNF and gene-expression work gives clear measurement targets.
- Intranasal delivery designs: Semax, whose animal and human studies are built around that route.
- Replicating the published clinical record in stroke and dementia: Cerebrolysin, which has the larger randomised placebo-controlled trials.
- Neurotrophic activity as a whole: Cerebrolysin, where the question is what the mixture does rather than what any one peptide in it does.
Can Semax and Cerebrolysin be studied together?
They can be, and the Russian stroke literature is full of multi-agent regimens, but no published trial compares the two head to head or tests them as a pair. Because both are linked to BDNF and recovery after ischemia, a design using both would need separate arms to tell their contributions apart. Semax is also often compared with its sister peptide in Semax vs Selank.
How are Semax and Cerebrolysin supplied?
Semax comes as a 10 mg lyophilised vial, a ready-mixed Semax Nasal Spray (0.175 mL per press), and the combined Selank + Semax Nasal Spray. Cerebrolysin comes as a 60 mg vial. Vials are reconstituted with bacteriostatic water (see the Semax reconstitution guide and how long Semax lasts). Certificates of analysis are on the lab reports page, and every order ships from within Canada by Canada Post Xpresspost. Buying guides: Semax and Cerebrolysin.
Semax and Cerebrolysin are supplied for laboratory research use only. The studies above were clinical research using pharmaceutical preparations.
Frequently asked questions
What is the difference between Semax and Cerebrolysin?
Semax is a single synthetic seven-amino-acid peptide derived from ACTH(4-10). Cerebrolysin is a mixture of small peptides prepared from pig brain. Both are studied in stroke recovery and linked to neurotrophic factors such as BDNF.
Is Semax stronger than Cerebrolysin?
No study has compared them directly, so there is no basis for ranking them. They are different kinds of material: Semax is one defined molecule studied mostly by the intranasal route, while Cerebrolysin is a mixture studied by infusion in larger randomised trials.
Is Cerebrolysin a peptide?
It is a peptide preparation rather than a single peptide: a porcine brain-derived peptide mixture with neurotrophic-factor-like properties.
Can Semax and Cerebrolysin be studied together?
They can, but no published trial has tested them as a pair. Because both are linked to BDNF and recovery after ischemia, a combined design needs separate arms to tell their contributions apart.
Where can I buy Semax and Cerebrolysin in Canada?
Vistara Labs supplies Semax as a 10 mg vial and ready-mixed nasal sprays, and Cerebrolysin as a 60 mg vial, shipped from within Canada by Canada Post Xpresspost with certificates of analysis on the lab reports page.
Product details from vistaralabs.ca, October 2026. Sources: Dolotov OV et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res. 2006. PMID 16996037. Agapova TY et al. Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH 4-10. Neurosci Lett. 2007. PMID 17353092. Filippenkov IB et al. Novel insights into the protective properties of ACTH(4-7)PGP (Semax) peptide at the transcriptome level following cerebral ischaemia-reperfusion in rats. Genes (Basel). 2020. PMID 32580520. Gusev EI et al. Effectiveness of semax in acute period of hemispheric ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 1997. PMID 11517472. Gusev EI et al. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018. PMID 29798983. Plosker GL, Gauthier S. Cerebrolysin: a review of its use in dementia. Drugs Aging. 2009. PMID 19848437. Seidl LF, Aigner L. Comparing the biological activity and composition of Cerebrolysin with other peptide preparations. J Med Life. 2024. PMID 38737662. Muresanu DF et al. Cerebrolysin and Recovery After Stroke (CARS): a randomized, placebo-controlled, double-blind, multicenter trial. Stroke. 2016. PMID 26564102. Guekht A et al. Safety and efficacy of Cerebrolysin in motor function recovery after stroke: a meta-analysis of the CARS trials. Neurol Sci. 2017. PMID 28707130. Heiss WD et al. Cerebrolysin in patients with acute ischemic stroke in Asia: results of a double-blind, placebo-controlled randomized trial. Stroke. 2012. PMID 22282884. Ziganshina LE et al. Cerebrolysin for acute ischaemic stroke. Cochrane Database Syst Rev. 2023. PMID 37818733. Gauthier S et al. Cerebrolysin in mild-to-moderate Alzheimer’s disease: a meta-analysis of randomized controlled clinical trials. Dement Geriatr Cogn Disord. 2015. PMID 25832905.
More on this: Peptides for Focus and Anxiety: What the Research Shows.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
