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Molecular Weight
Purity
Storage
Appearance
Solubility
01
Semax is a synthetic seven-residue peptide, Met-Glu-His-Phe-Pro-Gly-Pro. Its first four residues correspond to ACTH(4–7), a fragment of adrenocorticotropic hormone, and the C-terminal Pro-Gly-Pro extension improves stability. Like Selank, it was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences.
The ACTH(4–7) fragment lacks the regions needed for adrenal (cortisol-releasing) activity. Research has focused on Semax’s effects on neurotrophic factor expression, gene expression in brain injury models and related signalling. It is supplied as a lyophilized reference material for in vitro research only.
02
Semax combines an ACTH fragment with a stabilising tail.
ACTH(4–7): Met-Glu-His-Phe
This fragment includes part of the His-Phe-Arg-Trp sequence shared by melanocortin peptides, but not the full motif or the regions needed for adrenal stimulation.
Pro-Gly-Pro extension
The same three-residue tail used in Selank, added to slow enzymatic degradation.
Sensitive residues
Met1 is the main oxidation site (+16 Da). His3 and Phe4 provide some UV absorbance.
Termini
The N-terminus is a free amine and the C-terminus a free acid. N-Acetyl Semax Amidate and Adamax are versions with modified ends.
03
Published research on Semax includes several areas.
Neurotrophic factors
Animal studies have reported increased expression of BDNF and its receptor TrkB in brain regions such as the hippocampus and basal forebrain.
Ischaemia models
Gene expression studies in rodent models of focal brain ischaemia have examined effects on immune, vascular and neurotransmitter-related genes.
Melanocortin context
As an ACTH fragment, its relationship to melanocortin receptors has been examined, although it lacks the full high-affinity binding motif.
These findings are cited as research context only; no effects are claimed for this material.
04
Neurotrophic signalling studies
A reference compound in cell and tissue experiments measuring BDNF/TrkB-related expression.
Analogue comparisons
The parent compound for N-Acetyl Semax Amidate and Adamax, used to study how terminal modifications affect stability.
Oxidation studies
Its single N-terminal methionine makes it a simple model for methionine oxidation.
Analytical reference
A small peptide with one methionine and two aromatic residues, convenient for HPLC and LC-MS method checks.
05
Storage
Store the lyophilized powder at −20 °C, sealed, desiccated and protected from light.
Oxidation
Met1 oxidises in the presence of oxygen, trace metals and light. Use degassed buffers for sensitive work and minimise air exposure.
Reconstitution
Soluble in water and aqueous buffers.
Enzymatic breakdown
Peptidases in biological samples cleave Semax relatively quickly; the Pro-Gly-Pro tail slows this. Use protease inhibitors where intact peptide is needed.
Solutions
Prepare fresh or freeze single-use aliquots, and use low-binding tubes.
06
Semax is straightforward to analyse, with attention to methionine oxidation.
HPLC
Reversed-phase C18 with a TFA water/acetonitrile gradient. The Met-sulfoxide form is more polar and elutes slightly earlier.
Mass spectrometry
Positive-mode ESI shows [M+H]⁺ at m/z 814.4 and [M+2H]²⁺ at m/z 407.7 (monoisotopic). Oxidation appears at +16 Da.
Impurity profile
Typical checks include Met1 oxidation, truncated sequences, deletion sequences and counter-ion content.
07
Its first four residues are ACTH(4–7), Met-Glu-His-Phe, a fragment of adrenocorticotropic hormone. A Pro-Gly-Pro tail was added at the C-terminus to improve stability.
It lacks the regions of ACTH needed for adrenal (cortisol-releasing) activity, which is why it was developed as a separate research peptide.
Oxidation of Met1 to the sulfoxide (+16 Da), promoted by oxygen, trace metals and light.
Both are modified versions of Semax. N-Acetyl Semax Amidate adds an N-terminal acetyl group and a C-terminal amide; Adamax adds an N-terminal acetyl group and a C-terminal adamantane group.
[M+H]⁺ at m/z 814.4 and [M+2H]²⁺ at m/z 407.7 (monoisotopic), with an oxidised form at +16 Da if Met1 has oxidised.
No. It is supplied strictly as a reference compound for laboratory and analytical research and is not for human or animal use.
Semax Research Reference. (2026). Pure Peptides Labs Research Catalogue. Retrieved from https://purepeptideslabs.net/research-catalogue/neurochemical-research-peptides/semax/
Materials listed on this platform are supported by independent testing and published documentation for laboratory research contexts.
