Quick answer: Semax is a synthetic seven-amino-acid peptide derived from a short fragment of adrenocorticotropic hormone (ACTH), with a C-terminal Pro-Gly-Pro extension (stabilizing tail) that increases resistance to enzymatic degradation. The published research characterizes it mostly in brain-derived neurotrophic factor (BDNF) signaling and cerebrovascular models, and it is one of the most heavily studied compounds in the Russian neuropeptide literature. It is an approved clinical drug in Russia, but it is not approved anywhere in the West, and Velora supplies it strictly as a research compound.
Research use only: what this article is, and what it isn’t
This article is a research reference for scientists evaluating Semax for in-vitro or preclinical work. It is not medical advice, and it is not a guide to human use.
Semax is not approved by the U.S. Food and Drug Administration, the European Medicines Agency, or any other Western regulator for any therapeutic indication. It is approved as a clinical pharmaceutical in Russia under regional regulators and is marketed there in a 0.1% intranasal formulation, but that regional clinical product is not the same thing as a research-grade peptide. The Semax that Velora Research supplies is a lyophilized research compound sold strictly for laboratory research use, not for human consumption, veterinary use, or any personal, nutritional, or cosmetic application.
Every effect described below comes from published preclinical or clinical literature and is framed as an observation in a research model, not a benefit to a person. Researchers are responsible for compliance with all applicable law, including the Federal Food, Drug, and Cosmetic Act (21 U.S.C. § 331, § 355, § 360bbb-3), and institutional review requirements.
What Semax actually is
The sequence tells the story. Semax is a heptapeptide, derived from the ACTH (4-10) region consisting of the ACTH (4-7) pharmacophore with a C-terminal Pro-Gly-Pro extension, Semax has the sequence Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH fragment, a short piece of adrenocorticotropic hormone that lacks the hormonal activity of the full molecule but retains signaling behavior in the nervous system. The last three residues, Pro-Gly-Pro, are a stabilizing extension that slows enzymatic degradation, the same design choice used in its sister peptide Selank.
Semax was developed in the 1980s at the Institute of Molecular Genetics of the Russian Academy of Sciences. Its molecular weight is approximately 813.93 g/mol, with the molecular formula C37H51N9O10S and CAS number 80714-61-0. In the literature it is sometimes written simply as MEHFPGP, its single-letter sequence.
The important conceptual point is that Semax is a fragment analog: it borrows a piece of a hormone, drops the hormonal function, and keeps a regulatory signaling role that the research has characterized largely in neurotrophic and cerebrovascular models.
What has the research actually shown?
The Semax evidence base most consistently implicates modulation of the BDNF signaling pathway. BDNF is a protein that supports neuron growth, survival, and synaptic plasticity.
BDNF and trkB in the hippocampus. In rats, a single intranasal application of Semax was shown to regulate BDNF and trkB expression in the hippocampus, and the authors connected this to the peptide’s documented effects on learning (Dolotov et al., *Brain Research*, 2006). trkB is the receptor BDNF binds to, so a compound that affects both the ligand and its receptor is doing something coordinated rather than incidental.
BDNF protein in the basal forebrain. A companion study reported that Semax binds specifically in the rat basal forebrain and increases BDNF protein levels there, offering a molecular clue to the neurotrophic activity seen across the behavioral work (Dolotov et al., *Journal of Neurochemistry*, 2006). Taken together, the two 2006 papers give a reasonably specific mechanistic picture: Semax influences the BDNF system at both the protein and expression levels in these rat models.
Neurotrophins after cerebral ischemia. In a rat model of cerebral ischemia, Semax and its C-terminal Pro-Gly-Pro fragment were shown to activate the transcription of neurotrophins and their receptor genes, including BDNF, NGF, and TrkB (Dmitrieva et al., *Cellular and Molecular Neurobiology*, 2010). This cerebrovascular line of research is a large part of why Semax is so heavily represented in the Russian stroke literature.
Human neuroimaging. As with Selank, one of the few published human neuroimaging studies used resting-state functional MRI to examine how Semax affects whole-brain functional connectivity in 52 healthy participants (Panikratova et al., *Doklady Biological Sciences*, 2020). It is a useful anchor precisely because so much of the rest of the Semax evidence base is animal work.
If you are designing a study, the pattern is clear: the most consistently reported mechanistic finding is the BDNF signal and neurotrophic-factor mechanism, the cerebrovascular models are the second major cluster, and the direct human evidence remains limited relative to the volume of preclinical work.
Semax at a glance
| Attribute | Details |
|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP) |
| Class | Synthetic heptapeptide; ACTH (4–7) fragment analog |
| Molecular Weight | Approximately 813.93 g/mol (per Velora product specifications) |
| Molecular Formula | C37H51N9O10S |
| CAS Number | 80714-61-0 |
| Origin | Institute of Molecular Genetics, Russia, 1980s |
| Primary Research Areas | BDNF and neurotrophic research, cerebrovascular models, cognitive models, dopaminergic signaling, and melanocortin signaling |
| Regulatory Status (Russia) | Reported as an approved prescription medication in Russia under the Semax brand (0.1% intranasal formulation); verify current status against official regulatory sources. |
Reconstitution and concentration, in the units that matter
For a 10 mg vial, a common laboratory starting point is 2 mL of bacteriostatic water, giving a 5 mg/mL stock. Using Velora’s product-page molecular weight of 813.93 g/mol, that 5 mg/mL stock corresponds to approximately 6.14 mM. Cell-based assays that need nanomolar-to-micromolar working concentrations will require serial dilution in an assay-appropriate buffer; a 6.14 mM stock diluted 1:1,000 lands at roughly 6.14 µM.
The technique is the same as for any lyophilized peptide: add diluent slowly against the inner glass wall, swirl gently, and label the vial with the date and the final concentration in both mg/mL and mM. Confirm the molecular weight on your specific batch Certificate of Analysis before finalizing the molar math, because that number drives every downstream dilution.
For storage, follow standard peptide-chemistry practice: keep the lyophilized vial sealed at -20°C, protected from light, and refrigerate any reconstituted stock at 2 to 8°C. Velora has not published a specific reconstituted stability window for this product, so treat the usable timeframe as something to establish from your own protocol and the batch COA rather than a fixed shelf life.
Routes used in published research
Two administration routes dominate the published Semax research in animal models: intranasal and subcutaneous. The intranasal route is the one used throughout much of the Russian literature, which is also why “semax nasal spray” is such a common search term. For research purposes, the route in any protocol is a study-design decision to be selected and validated against the peer-reviewed literature and institutional approvals. None of these routes is a translation to human or veterinary use, and the Velora product is not sold for any such purpose.
Semax and Selank: the sister-peptide question
Semax and Selank get studied side by side so often that it is worth stating the difference plainly. Both are seven-amino-acid regulatory peptides from the same Russian institute, both carry the C-terminal Pro-Gly-Pro stabilization, and both are approved clinical drugs in Russia while remaining research-only in the West. The difference is origin and research focus. Semax descends from an ACTH (4-7) fragment and is most studied in BDNF, neurotrophic-factor, and cerebrovascular research. Selank descends from tuftsin and is most studied in anxiolytic and GABA-system research. For the full treatment of the other peptide, see our Selank research reference.
“The thing I find genuinely interesting about Semax from a chemistry standpoint is how tidy the mechanism story is. Two independent 2006 papers put the BDNF signal at both the protein and the expression level in the same animal models. That kind of convergence is rare, and it is exactly the sort of claim I want verified against the primary source rather than repeated secondhand. The COA on the vial is the other half of that discipline.”
Clark Jones, PhD, Velora Research
Working with verified material
Velora Research supplies Semax peptide as a 10 mg lyophilized research compound with a batch-specific third-party Certificate of Analysis. Each COA confirms identity by mass spectrometry and purity by HPLC at ≥99%, tied to the lot number on the vial. The same release protocol applies across the research peptide catalog, and the quality and testing process is documented end to end. For a compound whose research value rests on a specific sequence and a specific mechanism, confirming identity and purity before the peptide enters a study is not optional.
Frequently asked questions
What is Semax used for in research?
Published preclinical and clinical literature has characterized Semax across several research areas: BDNF and neurotrophic-factor expression, cerebrovascular and ischemia models, cognitive-behavior assays, and dopaminergic and melanocortin-receptor signaling. These are areas of published research interest observed in experimental systems. They are not therapeutic claims and do not describe outcomes in people.
Is Semax FDA-approved?
No. Semax is not approved by the FDA or the EMA for any indication. It is approved as a prescription medication in Russia, but that regional product is distinct from a research-grade peptide, and Velora’s Semax is supplied strictly for laboratory research.
What is Semax’s molecular weight?
Approximately 813.93 g/mol, with the formula C37H51N9O10S, per Velora’s product specifications. Confirm the value on your batch COA before calculating molar concentrations.
How does Semax differ from Selank?
Both are seven-amino-acid Russian-developed regulatory peptides sharing the Pro-Gly-Pro stabilization. Semax comes from an ACTH(4-7) fragment and is most studied in BDNF and cerebrovascular research; Selank comes from tuftsin and is most studied in anxiolytic and GABA-system research.
What is the sequence of Semax?
Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP). The first four residues are the ACTH (4-7) fragment; the last three are a stabilizing extension.
Sources and further reading
- Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH (4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Research. 2006;1117(1):54-60. PubMed
- Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain. Journal of Neurochemistry. 2006;97 Suppl 1:82-86. PubMed
- Dmitrieva VG, Povarova OV, Skvortsova VI, et al. Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia. Cellular and Molecular Neurobiology. 2010;30(1):71-79. PubMed
- Panikratova YR, Lebedeva IS, Sokolov OY, et al. Functional Connectomic Approach to Studying Selank and Semax Effects. Doklady Biological Sciences. 2020;490(1):9-11. PubMed
About the author
Clark Jones, PhD is a pharmaceutical scientist and medical writer with expertise in molecular biology, oncology, and chemistry. He has worked in the fields of oncology research, regenerative medicine, and pharmaceutical quality control. He has extensive experience with peptide formulations and development in research. In his work, he translates complex scientific literature into evidence-based content while maintaining regulatory and scientific integrity.
ORCID 0009-0005-9356-0297 · LinkedIn · More articles by Clark Jones
This article is provided for laboratory and scientific reference. Semax is a research compound, not an approved drug in the United States or European Union. The research-grade material Velora Research supplies is distinct from the Semax-brand pharmaceutical approved by regulators in Russia. Products sold by Velora Research are for in-vitro research use only and are not intended for human or veterinary use. Researchers are responsible for compliance with applicable laws and institutional protocols.
