Semax: ACTH(4-10) Analogue Research Guide (2026)
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Introduction (research-only scope)
Semax is a synthetic heptapeptide developed at the Institute of Molecular Genetics in Moscow as an analogue of the ACTH(4-10) fragment of adrenocorticotropic hormone, stabilised with a Pro-Gly-Pro tail. Critically for research design, it lacks the hormonal activity of full-length ACTH. This guide covers what it is, what the literature reports and how to verify research-grade material.
Research use only. The material described here is a laboratory reagent for in-vitro research by qualified professionals. It is not a medicine, supplement, cosmetic ingredient or veterinary product, is not for human or animal use, and nothing on this page is medical advice or a claim of effect in any person.
What is Semax?
Semax (molecular mass 813.92, CAS 80714-61-0) pairs the ACTH(4-10) sequence with the same stabilising tail used in Selank, which is why the two peptides are routinely compared; see Selank vs Semax. Peptra Labs supplies it as a lyophilised research reagent, 10 mg per vial.
How the reported mechanism works
Neurotrophin expression
The mechanism most consistently reported is an effect on neurotrophin biology: a 2007 study in Neuroscience Letters described changes in BDNF and NGF gene expression in rat brain after Semax administration. Downstream work has examined ischaemia and cognitive-load models on that basis.
Why the missing hormonal activity matters
Because the fragment does not carry the steroidogenic activity of full ACTH, researchers can probe the behavioural and neurotrophic arms of that peptide family without the confounding endocrine response, which is the main reason Semax became a tool compound.
What the published evidence covers
Semax is a registered medicine in Russia with an associated Russian-language clinical literature, and a smaller international preclinical record. A 2024 paper in the European Journal of Pharmacology tested Semax alongside melanotan II in a rat chronic unpredictable stress model, one of the few recent studies to place it beside another melanocortin-family analogue. The recurring caution applies: independent replication outside the originating circle remains limited, and no EU or US clinical programme exists.
How to verify a Semax research peptide is real and pure
Two tests answer two different questions: mass spectrometry confirms identity (expected molecular mass 813.92), HPLC quantifies purity. Our specification is at least 98%. Check the batch number printed on your vial against the lab reports archive: where a batch has been tested, its report is published there and links to the testing laboratory’s own verification page. If your batch is not listed yet, ask us for its documentation before use; a “typical” certificate is not evidence for a specific vial. See how to read a certificate of analysis.
Storage and reconstitution
Store the lyophilised material sealed, dry and protected from light at 2 to 8 °C for routine laboratory use, colder for long-term archiving. After reconstitution with bacteriostatic water, keep refrigerated and use within the window your protocol defines; repeated freeze-thaw cycles degrade peptides. General handling for all our reagents is in the peptide storage protocol.
Regulatory status
Semax is a registered medicine in Russia, typically as a nasal formulation, and has no marketing authorisation in the European Union, the United Kingdom or the United States; research material is not that medicinal product. It is not named individually on the WADA Prohibited List, but section S0 covers substances without approval for human therapeutic use. Research-grade material supplied here is not a medicine and is for in-vitro laboratory use only. The wider framework, including anti-doping status, is described in the peptide risk profile.
Why labs choose our Semax
Batch-numbered vials, published reports where a batch has been tested, shipping from an EU warehouse with tracking (no customs inside the EU) and prices shown with VAT included. Product page: Semax 10 mg. Country-by-country sourcing questions are covered in the buyer guide Buy Semax in Europe.
References
- Dolotov OV et al. Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH 4-10. Neurosci Lett. 2007. PubMed 17353092
- Antidepressant-like and antistress effects of the ACTH(4-10) synthetic analogs Semax and Melanotan II on male rats in a model of chronic unpredictable stress. Eur J Pharmacol. 2024. PubMed 39442746