Description
PrymaLab · Research Use Only
Semax Nasal Spray
Met-Glu-His-Phe-Pro-Gly-Pro · CAS 80714-61-0 · 813.9 Da
Semax nasal spray supplies the heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro, CAS 80714-61-0, molecular weight 813.9, in a metered spray format. The sequence joins the ACTH(4-10) fragment MEHF to a Pro-Gly-Pro extension that slows enzymatic breakdown.
Specification Table
| Property | Value |
|---|---|
| Compound | Semax |
| CAS number | 80714-61-0 |
| Molecular formula | C37H51N9O10S |
| Molecular weight | 813.92 g/mol |
| Residue count | 7 |
| Single-letter sequence | MEHFPGP |
| Three-letter sequence | Met-Glu-His-Phe-Pro-Gly-Pro |
| Parent fragment | ACTH(4-10), residues 4 to 10 of adrenocorticotropic hormone |
| Extension | Pro-Gly-Pro at the carboxy terminus |
| Purpose of the extension | Slows exopeptidase cleavage |
| Melanocortin receptor activity | Reported as negligible. The MEHF fragment lacks the core melanocortin pharmacophore |
| Originating programme | Institute of Molecular Genetics, Russian Academy of Sciences |
| Oxidation-prone residues | Methionine at position 1 |
| Format | Metered nasal spray, solution state |
| Physical state | Aqueous solution, supplied ready to use |
| Appearance | Clear colourless solution |
| Purity | Per lot-specific certificate of analysis |
| Storage | 2-8°C, protected from light. Do not freeze |
| Human clinical data outside Russia | None published |
| Regulatory status | No approved human or veterinary formulation in the United States |
What Semax Nasal Spray Dosage Appears in Published Research?
This is the most searched question about the compound, so it is worth answering with the actual figures rather than avoiding it. Everything below is an amount used in a published study, in the species that study used.
Rodent work from the originating programme and from independent groups has used intranasal amounts in the range of roughly 0.05 to 5 mg/kg, with most behavioural and biochemical studies clustering between 0.1 and 0.6 mg/kg. Ashmarin and colleagues reported effects in this band, and later groups have generally worked inside it.
Russian clinical literature describes intranasal amounts in the low milligram range per exposure. That literature sits largely outside the databases most researchers use and has not been replicated in Western trials, so it should be read as a starting reference rather than as established pharmacology.
Converting a rodent mg/kg figure to any other species is not a matter of multiplying by body weight. Allometric scaling accounts for differences in metabolic rate and surface area, and the FDA body surface area conversion factors are the conventional method. A figure that has not been scaled is not transferable.
The spray format adds a second variable that the vial format does not have. What matters experimentally is the amount deposited on the nasal mucosa, and that depends on metered volume, concentration, spray plume geometry and how much drains to the throat. A metered actuation is not the same as an absorbed amount.
How Does Semax Nasal Spray Compare With Injection?
The route question is the second most searched and it has a real answer rooted in anatomy rather than preference.
Intranasal delivery offers two documented pathways. Most of the applied material is absorbed across the respiratory epithelium into systemic circulation, behaving much as a parenteral exposure would. A smaller fraction reaches the olfactory epithelium at the roof of the nasal cavity, where transport along the olfactory and trigeminal nerve routes can bypass the blood-brain barrier.
That second pathway is why intranasal delivery attracts interest for centrally acting peptides. It is also frequently overstated. The olfactory region occupies a small share of human nasal surface area, considerably less than in rodents, so the fraction of an applied amount reaching it directly is small.
Bioavailability for peptides delivered this way is generally low and variable. Published figures across peptides of this size range from under one percent to the low tens of percent, and the variance between subjects is wide. Injection gives a known quantity into circulation. A spray does not.
For research purposes that variance is the deciding factor. If the question concerns receptor pharmacology or concentration-response, the vial format with a measured injection gives a defensible number. If the question concerns the intranasal route itself, the spray is the object of study.
What Does the Pro-Gly-Pro Extension Do?
Three of the seven residues are the extension, and the reason is enzymatic stability.
The parent fragment, MEHF, corresponds to residues 4 through 7 of adrenocorticotropic hormone. A four-residue peptide is degraded quickly by exopeptidases working inward from both termini, which limits how long it persists in any biological system.
Proline resists that. Its side chain bonds back to the backbone nitrogen and forms a ring, which constrains the local geometry and makes the adjacent peptide bond a poor substrate for enzymes that evolved to process ordinary residues. Placing prolines at positions 5 and 7 shields the carboxy end.
Selank uses the identical strategy, appending Pro-Gly-Pro to the tuftsin tetrapeptide. Both compounds came from the same Russian programme, and recognising the shared design tells you where the supporting literature is concentrated.
One consequence is worth noting for anyone reading the melanocortin literature alongside this. Although Semax derives from ACTH, the fragment it uses lacks the His-Phe-Arg-Trp core that melanocortin receptors recognise, and reported receptor activity is negligible. Whatever this peptide does, it does not appear to do it through those receptors.
How Should Semax Nasal Spray Be Stored?
Solution-state storage carries requirements the lyophilized vial does not, and the methionine at position 1 is the specific concern.
Methionine oxidises to the sulfoxide, adding 16 daltons and altering the residue. In dry powder that process is slow. In aqueous solution with dissolved oxygen and an air headspace above it, the rate rises considerably. A spray bottle draws air in with every actuation, which replenishes that headspace.
Keep the bottle refrigerated at 2 to 8 degrees Celsius and return it promptly after use rather than leaving it at room temperature between sessions. Protect it from light. Do not freeze, because the pump mechanism is not built to tolerate the volume change and the seal can fail.
Record the date of first actuation on the bottle itself. For a solution-state product with a pump, elapsed in-use time is the variable that determines how much oxidation has accumulated, and no label carries that information.
Where a measurement depends on knowing concentration accurately, mass spectrometry on a withdrawn sample will show whether a plus-16 satellite has grown relative to the 813.92 principal peak. That check takes minutes and it is the only way to know what a bottle in service still contains.
What Is Actually in a Nasal Spray Besides the Peptide?
A spray is a formulation, not just a compound in water, and the excipients affect both the peptide and the experiment.
Osmolality is the first. Nasal epithelium tolerates a narrow range, and a solution far from isotonic irritates the mucosa and changes clearance rate. Sodium chloride is the usual agent for adjusting it. A formulation that has not been adjusted will behave differently from one that has.
pH matters for two reasons at once. Nasal mucosa sits around pH 5.5 to 6.5, and peptide stability is pH-dependent. Those two constraints do not always point the same way, so the chosen buffer is a compromise, and it should be stated on the certificate rather than left unspecified.
Preservatives appear in most sprays intended for repeated use, because a pump draws air and contaminants back in. Benzalkonium chloride is the common choice and it is not inert: it affects ciliary function and it can interact with peptides. Where a formulation is preservative-free, the container must be designed for it and in-use shelf life shortens.
Viscosity agents such as hydroxypropyl methylcellulose slow drainage down the throat, which raises the fraction staying on the mucosa. They also change plume geometry, so two sprays with identical peptide concentration can deposit different amounts.
For anyone comparing a spray against a vial, these are the variables that make the comparison inexact. The vial contains the peptide. The spray contains the peptide plus a delivery system, and the delivery system is doing part of the work.
What Should a Certificate of Analysis Show?
A seven-residue peptide is straightforward to characterise, so a thin certificate has no excuse behind it.
Mass confirmation against 813.92 by high-resolution mass spectrometry, with the oxidised fraction quantified rather than merely absent from the report.
Purity by reversed-phase chromatography. At seven residues the deletion sequences separate cleanly, so a well-run gradient gives a purity figure that means something.
Concentration in the finished solution, determined analytically rather than calculated from the mass weighed into a batch. For a spray product this is the field most often stated as nominal.
Counterion identity and net peptide content. At 813.92 daltons a trifluoroacetate counterion represents a meaningful share of weighed mass, which shifts the molar figure.
Fill date. Degradation in a solution-state product runs from the moment the solution exists, not from the moment it is delivered.
Published Literature
References verified against the publisher record or a primary index. Much of the Semax literature originates from the Russian programme that developed it and appears in Russian-language journals, which is discussed above.
- Ashmarin IP, Nezavibatko VN, Levitskaya NG, Koshelev VB, Kamensky AA. Neuroscience Research Communications. 1995;16(2):105-112.
- Kaplan AY, Kochetova AG, Nezavibatko VN, Rjasina TV, Ashmarin IP. Neuroscience Research Communications. 1996;19(2):115-123.
- Dolotov OV, Karpenko EA, Inozemtseva LS, Seredenina TS, Levitskaya NG, Rozyczka J, Dubynina EV, Novosadova EV, Andreeva LA, Alfeeva LY, Kamensky AA, Grivennikov IA, Myasoedov NF, Engele J. Brain Research. 2006;1117(1):54-60.
- Shevchenko KV, Nagaev IY, Andreeva LA, Shevchenko VP, Myasoedov NF. Russian Journal of Bioorganic Chemistry. 2006;32(1):55-62.
- Illum L. Journal of Pharmacy and Pharmacology. 2004;56(1):3-17.
- Lochhead JJ, Thorne RG. Advanced Drug Delivery Reviews. 2012;64(7):614-628.
Frequently Asked Questions
What is Semax nasal spray?
A metered spray supplying the heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro, CAS 80714-61-0, molecular weight 813.92, in solution. The sequence joins the ACTH(4-10) fragment to a Pro-Gly-Pro extension. Laboratory research use only, with no approved formulation in the United States.
What Semax nasal spray dosage appears in the literature?
Rodent studies have used intranasal amounts of roughly 0.05 to 5 mg/kg, with most clustering between 0.1 and 0.6. Russian clinical literature describes low milligram amounts per exposure. These are figures from published studies in the species those studies used, not recommendations.
Can a rodent figure be converted to another species?
Not by body weight alone. Allometric scaling accounts for differences in metabolic rate and body surface area, and the FDA body surface area conversion factors are the conventional method. An unscaled figure does not transfer between species.
Why is a metered actuation not the same as an absorbed amount?
Because deposition depends on metered volume, solution concentration, spray plume geometry and how much drains to the throat rather than staying on the mucosa. The amount that reaches the epithelium is smaller than the amount the pump releases, and the gap varies.
How does the nasal route compare with injection?
Injection delivers a known quantity into circulation. Intranasal delivery gives low and variable bioavailability, with published figures for peptides of this size ranging from under one percent to the low tens of percent, and wide variance between subjects.
Does intranasal delivery bypass the blood-brain barrier?
Partly, and less than commonly claimed. A fraction reaching the olfactory epithelium can travel along olfactory and trigeminal nerve routes. That region is a small share of human nasal surface area, considerably smaller proportionally than in rodents, so the directly transported fraction is small.
What does the Pro-Gly-Pro extension accomplish?
It slows exopeptidase degradation. Proline constrains backbone geometry because its side chain bonds back to the nitrogen, which makes the adjacent bond a poor substrate for enzymes that process ordinary residues. Selank uses the same strategy on a different core.
Does Semax act on melanocortin receptors?
Reported activity is negligible. Although the sequence derives from ACTH, the MEHF fragment lacks the His-Phe-Arg-Trp core that melanocortin receptors recognise, so whatever this peptide does it does not appear to work through them.
How should the spray be stored?
Refrigerated at 2 to 8 degrees Celsius, protected from light, never frozen. The pump mechanism is not built for the volume change that freezing produces, and the seal can fail. Return the bottle to cold storage promptly rather than leaving it out between sessions.
Why does the methionine matter for a spray?
It oxidises to the sulfoxide, adding 16 daltons. That happens slowly in dry powder and considerably faster in aqueous solution with an air headspace, and a spray bottle draws fresh air in with every actuation, which keeps replenishing that headspace.
How can oxidation be checked?
Mass spectrometry on a withdrawn sample will show whether a satellite peak 16 daltons above the 813.92 principal has grown. It takes minutes and it is the only way to know what a bottle already in service still contains.
What should the certificate state?
Mass against 813.92 with the oxidised fraction quantified, purity by reversed-phase chromatography, analytically determined solution concentration rather than nominal, counterion identity with net peptide content, and the fill date. Degradation runs from when the solution was made.
Compliance Statement
Semax nasal spray is sold exclusively for laboratory research use. It is not a drug, food, or cosmetic product, and it is not a dietary product of any kind. It is not approved by the FDA or any comparable authority for human or veterinary use, no approved human or veterinary formulation exists in the United States, and amounts cited on this page are figures from published studies in the species those studies used. This product is not intended to diagnose, treat, cure, or prevent any disease. It must not be given to humans or animals. Purchase is restricted to qualified researchers and institutions operating within applicable laws. All handling is the responsibility of the purchasing laboratory.
Other formats of Semax
Semax is also stocked as Semax 1mg/ml preloaded 3ml pen, Semax 5mg and Semax 11mg. Each listing states its own quantity and concentration, and the pen and vial comparison explains what changes between formats.
19 reviews for Semax 10mg Nasal Spray