Semax 5mg

What is Semax ?

Semax is a synthetic heptapeptide analogue of the ACTH(4-10) fragment, studied in rats for its effects on BDNF and other neurotrophins. Nearly all of its literature comes from Russian research groups. We sell Semax in 5mg and 10mg vials of white lyophilised powder.

Semax has the sequence Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP). Its formula is C₃₇H₅₁N₉O₁₀S, its molecular weight 813.9 g/mol and its CAS number 80714-61-0. PubChem lists it as ACTH(4-7)-Pro-Gly-Pro.

The Met-Glu-His-Phe core comes from ACTH(4-10), and the Pro-Gly-Pro tail was added to slow enzymatic breakdown. Semax has none of the hormonal activity of ACTH. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences.

Semax Research Applications

• BDNF and trkB : a single application raised BDNF protein and trkB activation in rat hippocampus (Dolotov et al., Brain Res, 2006).
• Fast, region-specific gene changes : within an hour, BDNF and NGF expression rose in rat hippocampus while NGF fell in frontal cortex (Agapova et al., Neurosci Lett, 2007).
• Ischaemia model : Semax reduced cortical infarct volume after focal photo-induced ischaemia of the prefrontal cortex (Romanova et al., Bull Exp Biol Med, 2006).

Semax research is almost all preclinical and done in rats. Endpoints are neurotrophin gene and protein expression, trkB activation, infarct volume and conditioned avoidance tasks. Independent replication outside Russia is sparse.

Semax vs Adamax and Other ACTH-Derived Analogues

Semax, Adamax and Selank share one design: a short active fragment protected by a C-terminal Pro-Gly-Pro. Semax carries the ACTH-derived Met-Glu-His-Phe core. Adamax comes from the same design line, but has little peer-reviewed characterisation outside the Russian literature, so Semax findings do not transfer to it. Selank puts the same tail on tuftsin, a Thr-Lys-Pro-Arg fragment of immunoglobulin G. Because the tail is shared, Semax and Selank are often studied side by side.

Research Overview

Semax is a synthetic heptapeptide derived from the adrenocorticotropic hormone (ACTH) fragment 4-10, with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Developed by the Institute of Molecular Genetics of the Russian Academy of Sciences, Semax has been approved as a pharmaceutical agent in Russia and Ukraine for neurological applications. Research focuses on its ability to modulate brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) expression, conferring neuroprotective properties particularly relevant to ischaemic brain injury research. Studies have documented its effects on dopaminergic and serotonergic neurotransmitter systems, suggesting broad neuromodulatory activity beyond simple ACTH fragment effects. Semax has been clinically documented in stroke rehabilitation literature, where its neuroprotective and neurorestorative properties have been examined in post-ischaemic recovery models. The peptide crosses the blood-brain barrier efficiently, enabling central nervous system activity following peripheral administration. Researchers in neuroscience and cognitive pharmacology consider Semax a significant tool for studying neuroplasticity, neurotrophic factor regulation, and cognitive enhancement mechanisms in preclinical and clinical contexts.

Structurally Semax is ACTH(4-10) carrying a Pro-Gly-Pro extension at the C-terminus, and that tripeptide tail is the functionally important part of the design rather than an inert addition. PGP resists aminopeptidase cleavage, which is what gives the molecule a usable duration where the bare ACTH fragment has almost none. Critically, Semax retains the neurotropic activity of the parent fragment while being devoid of its corticotropic activity, so it does not drive adrenal steroidogenesis the way ACTH itself does. That separation of activities is the single most important pharmacological fact about the compound.

The neurotrophic mechanism is the most studied. Dolotov and colleagues reported increased BDNF and TrkB expression in rat hippocampus following administration, and the wider literature describes effects on NGF signalling alongside modulation of dopaminergic and serotonergic transmission. Semax is registered as a pharmaceutical in Russia, where it is used in stroke and cognitive indications.

The limitation should be stated rather than glossed over. Almost the entire evidence base is Russian-language and originates from a small number of affiliated institutions, and independent replication in Western laboratories is sparse. Very few placebo-controlled trials are indexed in the major English-language databases. Semax holds no marketing authorisation in the UK, the EU or the US, and is supplied here as a lyophilised research chemical for in-vitro laboratory use only.

Storage and Reconstitution

Store sealed vials at -20°C, away from light and moisture, for up to 24 months. After reconstitution, keep the solution at 2-8°C and use it within 4 weeks. For longer storage, freeze single-use aliquots at -20°C. Repeated freeze-thaw cycles, light and dissolved oxygen all speed methionine oxidation.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

Let the vial reach room temperature and swab both stoppers with alcohol. Add the bacteriostatic water slowly down the inside wall of the vial, away from strong light, and keep the stopper open as briefly as possible. Swirl gently until the powder dissolves, without shaking. The solution should be clear and colourless.

• Avoid repeated freeze-thaw cycles. Prepare single-use aliquots from reconstituted stock for best experimental reproducibility.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Semax, an analog of ACTH(4-10), regulates BDNF and trkB expression in the rat hippocampus (Brain Res, 2006)
• Neuroprotective and antiamnesic effects of Semax in experimental ischaemic infarction (Bull Exp Biol Med, 2007)
• Neurotrophin gene expression in rat brain under the action of Semax (2007)

Published research on Semax is indexed on PubMed. See our full UK buyer's guide for Semax, UK buyer's guide for Semax 5mg and UK buyer's guide for Semax CoA.