Compound monograph

Semax

Semax is a synthetic heptapeptide corresponding to residues 4 to 7 of adrenocorticotropic hormone extended at the C-terminus with the tripeptide Pro-Gly-Pro.

Published: 2026-09-04Last updated: 2026-10-16Literature/identifier verification: 2026-10-16

Also known asACTH(4-7)-Pro-Gly-Pro

Regulatory peptide fragment analogs

Identity & nomenclature

Semax is a synthetic heptapeptide corresponding to residues 4 to 7 of adrenocorticotropic hormone extended at the C-terminus with the tripeptide Pro-Gly-Pro.

The PubChem record describes Semax as ACTH(4-7) extended with Pro-Gly-Pro. The catalog separately lists N-acetyl semax amidate, which carries an N-terminal acetyl group and a C-terminal amide; that is a distinct molecule with a different formula, mass, and registry number, and it is not covered by this record. Much of the published literature instead describes Semax as an ACTH(4-10) analogue. Both descriptions refer to the same molecule: Semax retains ACTH residues 4 to 7 (Met-Glu-His-Phe) and substitutes Pro-Gly-Pro for residues 8 to 10 (Arg-Trp-Gly). This record uses the ACTH(4-7)-plus-Pro-Gly-Pro form because it states the composition of the molecule rather than the fragment it was designed from.

Declared aliases and development codes: ACTH(4-7)-Pro-Gly-Pro.

Molecular properties

Molecular formula	C37H51N9O10S
Molecular mass	813.9 Da
CAS Registry Number	80714-61-0
PubChem CID	9811102
UNII	I5FAL2585H
One-letter sequence	MEHFPGP
Three-letter sequence	Met–Glu–His–Phe–Pro–Gly–Pro
Terminal groups	Free N-terminus; Free C-terminal carboxyl

Sequence Met-Glu-His-Phe-Pro-Gly-Pro. Met-Glu-His-Phe is residues 4 to 7 of human ACTH(1-39) (SYSMEHFRWGKPVGKKRRPVKVYPNGAEDESAEAFPLEF); Pro-Gly-Pro is the synthetic C-terminal extension, not an ACTH sequence. The molecular formula and average mass recorded below are the values derived from this sequence.

Structural characteristics

The design follows a fragment-plus-extension pattern: a short sequence taken from a larger endogenous regulatory peptide, extended with a C-terminal Pro-Gly-Pro tripeptide. Selank, also in this library, was constructed on the same pattern from a different parent fragment.

Terminal features: Free N-terminus, Free C-terminal carboxyl.

Molecular targets & mechanisms

Analytical considerations

The single sulfur atom corresponds to the N-terminal methionine. Vanhee et al. (PMID 31667971) is cited here for formula and mass corroboration only, not as the original source of the Semax name-to-sequence mapping. Table 1 lists the reference standard purchased from Sigma Aldrich, lot 035M4701V, rather than a composition assigned to the seized material. Its C37H51N9O10S formula matches this record. The table reports 813.3480 Da monoisotopic mass; this library retains 813.9 Da average mass. These conventions describe the same composition. The N-acetylated, C-terminally amidated variant has a different composition and must be distinguished in identity analysis.

Disagreements and mix-ups

Points where sources disagree about this compound's identity, or where a name or form is easily confused with another, as noted in this record. The discrepancy register quotes the passage for each one.

Sources disagree · this Library follows one source · Description
Semax described as ACTH(4-7)-Pro-Gly-Pro or as an ACTH(4-10) analogue
Often mixed up · Name or substance
Semax vs N-acetyl Semax amidate

What the studies reported

Each finding describes one cited study in its stated model. These observations are specific to that study and do not establish effects in other settings.

Animal studies

Rat hippocampus
Dolotov et al. reported a maximal 1.4-fold increase in BDNF protein levels with Semax in the rat hippocampus.
Reference [2]
Rat hippocampus
Dolotov et al. reported a 1.6-fold increase in TrkB tyrosine phosphorylation levels with Semax in the rat hippocampus.
Reference [2]
Rat hippocampus
Dolotov et al. reported 3-fold and 2-fold increases in exon III BDNF and trkB mRNA levels, respectively, with Semax in the rat hippocampus.
Reference [2]

Verified bibliography

Cited studies by type

The 2 papers this record cites, counted by the kind of work each reports. A count is the size of this record's selection, not of the research that exists, and says nothing about results, safety, effectiveness or approval.

A paper can report more than one kind of work. Each count opens those papers in the bibliography. Compare every record on the Evidence Map.

Reference 1
The occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations: An incentive for controlling agencies to prepare for future encounters of the kind.
Vanhee C, Francotte A, Janvier S, Deconinck E
Drug testing and analysis · 2020-01-29 · Journal Article
current
PMID 31667971 DOI 10.1002/dta.2717 Selank Semax N-Acetyl Selank Amidate N-Acetyl Semax Amidate
Reference 2
Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus.
Dolotov OV, Karpenko EA, Inozemtseva LS, Seredenina TS, Levitskaya NG, Rozyczka J, Dubynina EV, Novosadova EV, Andreeva LA, Alfeeva LY, Kamensky AA, Grivennikov IA, Myasoedov NF, Engele J
Brain research · 2006-09-22 · Journal Article
current
PMID 16996037 DOI 10.1016/j.brainres.2006.07.108 Semax

Study models of these references

What kind of experiment each cited paper reports, taken from its abstract unless marked. Not a summary of results.

Reference	Study models
Vanhee C et al. 2020	Chemical, structural or analytical study; no biological model reported
Dolotov OV et al. 2006	Study models reported: animal (rat) · from the abstract

Compare

Semax vs N-Acetyl Semax Amidate: Sequence and Identity

Catalog listing

Record history

Published 2026-09-04.

2026-10-16: References
2026-10-14: Sequence and structure
2026-09-28: Analytical notes, References
2026-09-17: Identity and nomenclature, Sequence and structure

Each entry names the parts of this record that changed on that date. Changes to links between records and to catalogue links are not listed. This history covers the tracked record fields; study findings are not listed here.

Cite this record: Purely Peptides Research Library. Semax. Published 2026-09-04; updated 2026-10-16. https://purelypeptides.org/research/compounds/semax/

Methodology & citation verification

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