Semax Pen
3 mL of the MEHFPGP heptapeptide in bacteriostatic water at 1 mg/mL, 3 mg per pen. Filled from a Semax lot tested in the manufacturer’s own laboratory, with a lot certificate.
| Compound | Semax ACTH(4–7)-Pro-Gly-Pro heptapeptide (MEHFPGP) |
|---|---|
| CAS number | 80714-61-0 |
| Molecular formula | C37H51N9O10S |
| Theoretical mass | 813.9 Da |
| Sequence / structure | H-MEHFPGP-OH (7 residues; free N- and C-termini) |
| Contents | Semax: 3 mg per 3 mL pen (0.1% w/v) |
| Form | Sterile aqueous solution in bacteriostatic water (0.9% benzyl alcohol), supplied in a 3 mL glass cartridge inside a preloaded autoinjector pen fitted with a needle |
| Storage, sealed | Store at 2–8 °C in the original carton, protected from light |
| Format | Solution in a 3 mL pre-filled pen |
Sizes and lots
- 3 mg · 1 pen — $38.99
- 3 mg · Kit of 10 — $346.62
Semax is the heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro, built from residues 4 to 7 of ACTH with a Pro-Gly-Pro tail. Here it comes already dissolved: a preloaded autoinjector pen holding a 3 mL cartridge at 1 mg/mL, 3 mg of peptide in all, with no powder to handle. The Semax literature, nearly all of it from Russian groups, deals with neurotrophin expression in rat cells and brain and with how quickly the peptide is degraded.
What is in the pen
The cartridge holds 3 mL of sterile aqueous solution. Semax is present at 0.1% w/v, which is 1 mg/mL and 3 mg per pen, in bacteriostatic water preserved with 0.9% benzyl alcohol. The safety data sheet does not classify the peptide as hazardous. Benzyl alcohol is classified: harmful if swallowed or inhaled, a serious eye irritant and a possible skin sensitiser.
Keep the pen at 2 to 8 °C in its original carton, away from light, and keep it capped once in use. It must not be frozen; discard a pen whose solution has frozen, discoloured or turned cloudy. The freeze-dried Semax 5 mg vial is the alternative for work that needs the peptide dry and frozen until the day it is dissolved, and the general differences between the formats are set out in peptide pen vs vial.
What the research covers
Semax is an analogue of the ACTH(4-10) fragment that keeps Met-Glu-His-Phe and ends in Pro-Gly-Pro1. Its literature mostly asks whether it alters neurotrophin signalling. In glial cells cultured from the basal forebrain of newborn rats, Semax raised BDNF mRNA eightfold and NGF mRNA fivefold, peaking 30 minutes after it was added2. In the rat hippocampus, one application was followed by up to 1.4-fold more BDNF protein and more phosphorylated trkB, along with more conditioned avoidance reactions in a learning task1.
The pen raises a question those papers do not answer: how Semax behaves as a stored solution. The abstracts deal with tissue and cell culture, not with stability in a cartridge, and none used a preserved solution like this one. Methionine oxidation has been measured in proteins such as G-CSF, where the rate for each methionine shifted with pH and with the movement of the chain around it3, but no comparable measurement for Semax in bacteriostatic water is among the references here. The storage limits on the safety data sheet are the ones to follow.
Frequently asked questions
How does the pen differ from the Semax vials?
The vials hold freeze-dried Semax, stored at −20 °C and kept dry until the laboratory dissolves it. The pen holds 3 mg already in bacteriostatic water at 1 mg/mL and is stored at 2 to 8 °C. It trades the flexibility of dry powder for a fixed, ready concentration.
Why is the pen kept cold but never frozen?
Those are the storage terms on its safety data sheet: 2 to 8 °C, in the carton and away from light. The sheet says to discard a pen whose solution has frozen, discoloured or turned cloudy, which is why the pen and the dry vials follow different storage rules.
References
- 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 Res. 2006;1117(1):54-60. DOI · PubMed
- Shadrina MI, Dolotov OV, Grivennikov IA, et al. Rapid induction of neurotrophin mRNAs in rat glial cell cultures by Semax, an adrenocorticotropic hormone analog. Neurosci Lett. 2001;308(2):115-8. DOI · PubMed
- Chu JW, Yin J, Wang DI, et al. Molecular dynamics simulations and oxidation rates of methionine residues of granulocyte colony-stimulating factor at different pH values. Biochemistry. 2004;43(4):1019-29. DOI · PubMed
For laboratory research use only. Not for human or veterinary consumption. Products have not been evaluated by the U.S. Food and Drug Administration and are not intended to diagnose, treat, cure or prevent any disease.