Semax

Key facts

01 What Is Semax?

This synthetic heptapeptide was developed in Russia. Its first four residues are a fragment of adrenocorticotropic hormone (ACTH), and its last three are the tripeptide Pro-Gly-Pro. Papers usually describe it as an analogue of ACTH(4-10) ^[1].

FDA's Global Substance Registration System records it as SEMAX, with the synonym "ACTH (4-7), Pro-Gly-Pro-", which states the design in one line. Most of the literature comes from Russian laboratories, and it often appears next to Selank, which was built on the same principle from a different parent peptide.

Vinnix doesn't sell it as a standalone vial. It is one of the two components in the Selank + Semax research blend. This page covers the compound itself.

02 Semax Sequence and ACTH Origin

ACTH is a 39-residue hormone. Counting from its N-terminus, residues 4 to 7 read Met-Glu-His-Phe, and that stretch forms the front half of the molecule. The rest of the native hormone is dropped and replaced with Pro-Gly-Pro.

Ashmarin and colleagues grouped it with other hybrid peptides that pair a regulatory fragment with a glyproline tail ^[2]. Short ACTH fragments are broken down quickly by peptidases, and proline-rich C-terminal extensions are the standard explanation for the longer half-life reported for such hybrids ^[3]. An in vitro study tracked how the peptide itself is degraded by rat brain cell cultures and membranes ^[1].

The sequence has one acidic residue (glutamate), one histidine and no lysine or arginine. That gives the molecule a different charge profile from Selank, and the methionine at position 1 supplies the single sulfur atom in its formula.

03 Molecular and Registry Data

Values below come from PubChem and FDA GSRS and describe the free peptide. Counter-ions in a supplied powder change its bulk weight but not the molecular formula (see what a molecular formula tells you).

04 Published Research

Most of this research is preclinical and was published by a small number of Russian groups. The examples below show the study types you'll meet.

• Degradation. An in vitro study followed how the peptide is broken down by rat basal forebrain cell cultures and plasma membranes ^[1].
• Gene expression. An animal study used genome-wide transcriptional analysis in a rat model of focal brain ischemia ^[4].
• Enzyme studies. An in vitro study compared Semax and Selank against enkephalin-degrading enzymes in human serum ^[5].
• Animal models. A rat study examined both peptides in a 6-OHDA lesion model ^[6].

These findings don't establish safety or any effect in people, and it is not an approved medicine in the United States. Our in vitro vs. in vivo guide explains how to weigh each study type.

05 Laboratory Identification

Mass spectrometry should show a neutral mass of 813.35 Da, seen near m/z 814.36 as the singly protonated ion. One detail is specific to this peptide: methionine oxidizes easily to methionine sulfoxide, which adds 16 Da. A careful report looks for that +16 signal and counts it as an impurity. HPLC purity and the per-component approach for blends are covered in peptide testing and analysis.

06 Vinnix Products That Contain Semax

Vinnix offers this compound only in the Selank + Semax blend (SKU XS20, 20 mg total per vial), with the amount of each peptide given on the batch record. Batch reports go into the COA Library as each batch is released; match the batch number on the vial to its report.

REFScientific references

1. Zolotarev YA, Dolotov OV, Inozemtseva LS, et al. Degradation of the ACTH(4-10) analog Semax in the presence of rat basal forebrain cell cultures and plasma membranes. Amino Acids. 2006;30(4):403-408. PubMed 16773243
   in vitro study
2. Ashmarin IP, Samonina GE, Lyapina LA, Kamenskii AA, et al. Natural and hybrid ("chimeric") stable regulatory glyproline peptides. Pathophysiology. 2005;11(4):179-185. PubMed 15837162
   review
3. Shevchenko KV, Nagaev IY, Andreeva LA, Shevchenko VP, Myasoedov NF. [Stability of proline-containing peptides in biological media]. Biomed Khim. 2019;65(3):180-201. PubMed 31258142
   review
4. Medvedeva EV, Dmitrieva VG, Povarova OV, et al. The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia: genome-wide transcriptional analysis. BMC Genomics. 2014;15:228. PubMed 24661604
   animal study
5. Kost NV, Sokolov OIu, Gabaeva MV, et al. [Semax and selank inhibit the enkephalin-degrading enzymes from human serum]. Bioorg Khim. 2001;27(3):180-183. PubMed 11443939
   in vitro study
6. Slominsky PA, Shadrina MI, Kolomin TA, et al. Peptides semax and selank affect the behavior of rats with 6-OHDA induced PD-like parkinsonism. Dokl Biol Sci. 2017;474(1):106-109. PubMed 28702721
   animal study