Semax: An ACTH(4–10) Analog — Sequence, Origin and BDNF Studies

Compound Profile · By SCA Team · 3 min read · Last updated October 5, 2026

1. Identity and structure

2. Design rationale

Short ACTH fragments such as ACTH(4–10) attracted interest in the 1970s because they retained some activity of the parent molecule without its adrenal effects, but they are cleaved quickly. Semax keeps the ACTH(4–7) core and adds the proline-rich Pro-Gly-Pro motif at the C-terminus, which slows enzymatic breakdown. The same extension strategy was later used for Selank.

3. Origin

Semax was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences together with Moscow State University. Most of the published molecular work on the compound comes from these groups.

4. BDNF and trkB studies

Dolotov and colleagues (2006) reported that Semax changed the expression of BDNF and of its receptor, the tyrosine kinase trkB, in the rat hippocampus, and described specific binding sites for Semax in the rat basal forebrain. BDNF is a member of the neurotrophin family of growth factors.

5. Analytical characterization

Identity and purity are confirmed analytically for every lot. Reversed-phase HPLC with UV detection quantifies chromatographic purity, and electrospray mass spectrometry (ESI-MS) confirms that the observed molecular mass matches the theoretical value for Semax.

Results are reported on a lot-specific certificate of analysis together with appearance, net content and the lot number, which allows any vial to be traced back to its analytical record.

6. Storage and handling

Material is supplied as a lyophilized solid in a sealed vial. Unopened vials are best kept at −20 °C, protected from light and moisture. Allow a vial to equilibrate to room temperature before opening to limit condensation, and record the lot number so the vial can be matched to its certificate of analysis.