Semax: A Plain-English Research Guide
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What is Semax?
Semax is a synthetic seven-amino-acid peptide (Met-Glu-His-Phe-Pro-Gly-Pro) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, the same institute behind Selank. It is built from a short fragment of ACTH (ACTH 4-7) with a stabilizing Pro-Gly-Pro tail added.1
ACTH is best known as the hormone that tells the adrenal glands to make cortisol. Short fragments of ACTH, however, were found to affect attention and learning in animals without that hormonal effect. Semax was designed to keep those brain effects while lasting longer than the natural fragment.1
Semax is a seven-amino-acid peptide built from a fragment of ACTH, studied in laboratory research on cognition, BDNF and brain protection in ischemia (stroke) models. Full Scale Peptides supplies it as a freeze-dried powder with a published COA, for research use only.
Semax at a glance
Amino acids
ACTH(4-7) plus a stabilizing Pro-Gly-Pro tail.
Parent hormone
Built from a short fragment studied for brain effects without adrenal stimulation.
Developed
Designed at the Institute of Molecular Genetics, Russian Academy of Sciences.
Our current lot
HPLC purity for lot FSP-SEM-072126-01, with identity confirmed by LC-MS.
How researchers think Semax works
1. BDNF and TrkB
BDNF (brain-derived neurotrophic factor) and its receptor TrkB support nerve-cell survival, growth and learning. A rat study found that Semax increased BDNF and TrkB levels in the hippocampus, a brain region central to memory.2 This is the most-cited mechanism behind its cognitive research profile.
2. Gene expression after ischemia
In rat models of stroke (focal brain ischemia), Semax changed the activity of many genes, especially those involved in the immune response and blood vessels.3 More recent work reported that ACTH-like peptides, including Semax, partly reversed the gene-expression disruption caused by an experimental stroke.4
3. Resistance to low oxygen
Early studies reported that Semax increased resistance to hypoxia (low oxygen), which ties into its stroke-model research.5
This page summarizes published laboratory and animal research. It does not describe any use of Semax in people or animals. Semax from Full Scale Peptides is sold strictly for laboratory research.
What scientists study Semax for
- Cognition. Attention, learning and memory in animal models.12
- Neuroplasticity. BDNF and TrkB signaling in the hippocampus.2
- Stroke models. Brain gene expression and protection after focal ischemia.34
- Hypoxia. Resistance to low-oxygen conditions.5
- Comparisons with Selank. The two sister peptides are often studied side by side.
Most Semax research comes from Russian research groups, and much of it appears in Russian-language journals with limited independent replication elsewhere. Semax is registered as a medicine in Russia but not in the U.S. or Europe. Treat the findings as leads for further study.
Semax 10mg, research grade
Freeze-dried powder with a third-party COA published before you buy, and tracked U.S. shipping. For laboratory research use only.
Purity and testing: why the COA matters
Semax contains methionine, an amino acid that oxidizes easily, so confirming the intact sequence matters. Every Semax lot from Full Scale Peptides is tested by an independent lab, Freedom Diagnostics, before it is sold. HPLC measures purity, LC-MS confirms the sequence, and the full report is published before you buy.
- Lot
- FSP-SEM-072126-01
- Tested
- Jul 28, 2026
- Lab
- Freedom Diagnostics
- Measured content
- 12.42 mg (10 mg labeled)
- Accession #
- 2607240452
- Report
- View full COA
New to reading lab reports? See how to read and verify a Certificate of Analysis and why 99%+ purity matters in research.
How Semax is handled in the lab
Semax ships as a lyophilized (freeze-dried) powder, meaning the water has been removed to keep the peptide stable. Store sealed vials at −20 °C, protected from light. Before use in research it is reconstituted, or dissolved back into a liquid, usually with bacteriostatic water. Handling it the same careful way every time keeps results consistent:
- Let the sealed vial come to room temperature before opening it, to limit condensation.
- Add the water slowly down the inside wall of the vial, not directly onto the powder.
- Swirl gently until the powder is fully dissolved. Don’t shake it.
- Label the vial with the date, keep it refrigerated at 2–8 °C away from light, and avoid repeated freeze–thaw cycles.
For more detail, see our reconstitution guide and storage and handling best practices.
Key takeaways
- Semax is a seven-amino-acid peptide built from a fragment of ACTH, developed in Russia.
- It is designed for brain effects without adrenal (cortisol) stimulation.
- It increased BDNF and TrkB in the rat hippocampus, its most-cited mechanism.
- It is studied in stroke and hypoxia models, mostly by Russian research groups.
- Our current lot tests at 99.27% purity, with identity confirmed by LC-MS and the full COA published. For laboratory research use only.
Frequently asked questions
What is Semax made from?
It is based on ACTH(4-7), a short fragment of the hormone ACTH, with a Pro-Gly-Pro tail added for stability, for seven amino acids in total.
Does Semax act like ACTH?
No. It was designed to keep the brain effects of ACTH fragments without stimulating the adrenal glands to make cortisol.
What is the difference between Semax and Selank?
Both come from the same Russian institute. Semax is based on an ACTH fragment and is studied mainly for cognition and brain protection, while Selank is based on tuftsin and is studied mainly for anxiety-related effects. See our Selank guide.
What purity is Full Scale Peptides' Semax?
The current lot (FSP-SEM-072126-01) measured 99.27% purity by HPLC, with identity confirmed by LC-MS at Freedom Diagnostics. The full Certificate of Analysis is published in our COA library.
How is Semax supplied and stored?
It ships as a 10 mg lyophilized powder in a sealed glass vial. Store unopened vials at −20 °C away from light. Once reconstituted, keep the vial refrigerated at 2–8 °C.
Is Semax for human or veterinary use?
No. The Semax we supply is sold strictly for laboratory research. It is not for human or veterinary use and must not be administered to people or animals.
Scientific references
The findings summarized on this page come from published scientific literature, available on PubMed. Full Scale Peptides did not conduct, fund or sponsor this research, and nothing here implies endorsement by the authors or their institutions. The studies describe research on Semax itself, not the product we supply.
- Asmarin IP, Nezavibat'ko VN, Miasoedov NF, et al. A nootropic adrenocorticotropin analog 4-10-Semax (15 years experience in its design and study) [in Russian]. Zh Vyssh Nerv Deiat Im I P Pavlova. 1997;47(2):420–430. PMID: 9173745
- 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. PMID: 16996037
- Medvedeva EV, Dmitrieva VG, Limborska SA, et al. Semax, an analog of ACTH(4-7), regulates expression of immune response genes during ischemic brain injury in rats. Mol Genet Genomics. 2017;292(3):635–653. PMID: 28255762
- Filippenkov IB, Shpetko YY, Stavchansky VV, et al. ACTH-like peptides compensate rat brain gene expression profile disrupted by ischemia a day after experimental stroke. Biomedicines. 2024;12(12). PMID: 39767736
- Kaplan AIa, Koshelev VB, Nezavibat'ko VN, et al. Increased resistance to hypoxia effected by the neuropeptide preparation Semax [in Russian]. Fiziol Cheloveka. 1992;18(5):104–107. PMID: 1335426
Continue your research
For laboratory research use only. Not for human or veterinary use. The information on this page is provided for educational purposes and describes published research; it is not medical advice, and no statement here has been evaluated by the FDA.