Semax Peptide Pen (ACTH(4–10) Analogue) | 20mg

Semax is a synthetic heptapeptide developed at the Institute of Molecular Genetics in Moscow, supplied here pre-mixed at 20 mg in a 3 ml stabilised cartridge at a stated 6.67 mg/ml. No lyophilised powder, no reconstitution step, no separate diluent to source.

What Semax is

The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, and it reads in two parts. The first four residues, Met-Glu-His-Phe, are ACTH(4–7) — a fragment of adrenocorticotropic hormone. The final three, Pro-Gly-Pro, are a stabilising extension added to slow enzymatic degradation of that fragment, which is otherwise cleared within minutes.

The design point is that the fragment is short enough to have lost the parent hormone's endocrine function. ACTH acts at melanocortin receptors to drive corticosteroid release; ACTH(4–10) and its analogues do not, which is why Semax is studied as a neuropeptide rather than as a hormone analogue. It is the same construction method used for Selank, where the PGP tail is appended to tuftsin instead.

At 813.9 g/mol it is a small, highly soluble peptide. It carries a single methionine, which is the residue most prone to oxidation in the molecule and the reason light and air exposure matter more here than the size of the peptide would suggest.

Semax pen: the same thing under a shorter name

Most people searching for this product type “semax pen” rather than the full compound name, and the two mean the same thing. A semax pen is a pre-filled Semax cartridge in a dial-dosing pen, as opposed to lyophilised powder in a vial.

This pen holds 20 mg in a sealed 3 ml cartridge, at 6.67 mg/ml. The dial is graduated at 5 clicks = 300  mcg. Those are device figures — what the mechanism displaces, not what should be dispensed.

Applications in research

• Neurotrophin gene expression. The best-documented laboratory work measures BDNF and NGF transcript levels in rat brain tissue following Semax administration, with the temporal dynamics of expression as the endpoint.
• Vascular and hypoxia-response genes. Studies of Vegfa expression, including comparisons between Semax and its C-terminal PGP fragment alone, which separates the contribution of the extension from that of the ACTH fragment.
• Protein expression profiling. Proteomic characterisation in ischaemia models, where the peptide is applied as a defined stimulus and the readout is the expressed protein complement.
• Nitric oxide and oxidative stress. Work measuring nitric-oxide generation in brain tissue under stress conditions, with Semax and glycine as separate comparators.

Much of the Semax literature is Russian-language and comes from a small number of centres. It is genuine published work and it is narrow; that is an accurate description of the evidence base, and it concerns the molecule rather than this material.

A note on intranasal preparations

Semax is most often described in the literature in an intranasal form, and searches for it frequently return nasal-spray products. This is not a nasal spray. It is a pre-mixed solution in a dial-dosing cartridge supplied for laboratory research use, and no delivery route is specified or intended for it.

Is Semax legal in the UK?

Semax is not a licensed medicine in the United Kingdom and holds no MHRA marketing authorisation. It is registered as a medicine in Russia; that registration carries no weight here.

It is not a controlled drug under the Misuse of Drugs Act 1971, so buying and possessing it in the UK for laboratory research is lawful. Supplying it for human or veterinary consumption is not, and would engage the Human Medicines Regulations 2012. Every cartridge is labelled and supplied strictly for in-vitro research use.

What you are actually comparing between listings

• Total mass. This cartridge holds 20 mg. The standard UK presentation is a 5 mg vial, so one unit here carries roughly four times the peptide of a typical listing.
• Format. Pre-mixed solution at a stated 6.67 mg/ml against lyophilised powder requiring bacteriostatic water, a concentration calculation and whatever variance that step adds between preparations.
• Cost per milligram. At £110 for 20 mg this works out at £5.50 per mg, which is the figure that compares across listings.

Handling and storage

Store at 2–8 °C and protect from light. Keep the cartridge sealed until use, then upright, and observe aseptic technique. Do not freeze. The N-terminal methionine makes this peptide more susceptible to oxidation than its size implies, so minimise exposure to light, air and warmth. Orders placed before 2pm are dispatched the same working day, cold-packed, in plain outer packaging.

References

Literature on the molecule. These describe Semax as a compound and none is a claim about this product.

1. Agapova TY, Agniullin YV, Shadrina MI, et al. Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH(4–10). Neurosci Lett. 2007;417(2):201–5. PMID 17353092.
2. Glazova NY, Sebentsova EA, Manchenko DM, et al. Semax, synthetic ACTH(4–10) analogue, attenuates behavioural and neurochemical alterations following early-life fluvoxamine exposure in white rats. Neuropeptides. 2021;86:102114. PMID 33418449.
3. Bashkatova VG, Koshelev VB, Fadyukova OE, et al. Novel synthetic analogue of ACTH 4–10 (Semax) but not glycine prevents the enhanced nitric oxide generation in cerebral cortex of rats with incomplete global ischemia. Brain Res. 2001;894(1):145–9. PMID 11245825.

Research use only

This material is supplied strictly for in-vitro research and analytical purposes. It is not for human or veterinary administration and not for any diagnostic or therapeutic application. It holds no MHRA marketing authorisation. Confirm the current regulatory position before drafting institutional documentation, and clear the material through your own ethics, COSHH and biosafety processes before ordering.