Semax is a stabilised fragment of adrenocorticotropic hormone that has had its hormonal activity removed, leaving only the sequence associated with effects on the central nervous system.

What Is Semax?

ACTH is a 39-amino-acid pituitary hormone whose principal role is stimulating adrenal corticosteroid production. That activity resides in the N-terminal region. A separate fragment, ACTH(4-10), was found to act on the central nervous system in animal models without the steroidogenic activity of the full hormone.

Semax is ACTH(4-10) extended with a C-terminal Pro-Gly-Pro tripeptide. As with Selank, that extension markedly increases resistance to enzymatic degradation while preserving activity. The result is a heptapeptide retaining the neuroactive properties of the fragment without the endocrine effects of the parent hormone.

How Researchers Understand Its Mechanism

The most reproduced finding concerns brain-derived neurotrophic factor. Exposure has been associated with increased BDNF expression and increased expression of its receptor TrkB in hippocampal tissue in rodent models. Because BDNF signaling is central to synaptic plasticity, this is the mechanism most often discussed in the Semax literature.

A second strand concerns monoaminergic systems, with reported effects on dopaminergic and serotonergic transmission. A third concerns melanocortin receptors: as an ACTH fragment, Semax retains some structural relationship to melanocortin ligands, and interaction with these receptors in neural tissue has been proposed, though this is less firmly established.

No single receptor has been confirmed as the primary target, which remains an open question.

Areas of Scientific Investigation

Applications include neurotrophic factor expression research, neuronal culture systems, monoamine transmission studies, and comparative work with Selank examining the shared Pro-Gly-Pro stabilisation strategy.

Why Purity and Verification Matter

Reproducibility in peptide research depends on knowing exactly what is in the vial. Sequence-related impurities, truncated fragments and residual synthesis reagents can all influence experimental outcomes, and two preparations nominally of the same compound can behave differently if purity differs. Independent HPLC and mass spectrometry testing establishes both identity and purity, which is why third-party verification is standard practice for research-grade material. All compounds referenced here are supplied as lyophilized powder at 99%+ purity with independent verification.

Summary

Semax is a stabilised ACTH(4-10) analog lacking steroidogenic activity, studied principally for effects on BDNF and TrkB expression and on monoaminergic transmission. Its primary receptor target has not been established. It is intended strictly for laboratory research.

Related Research Peptides

Semax 10mg · Selank 10mg · Pinealon 10mg · VIP 5mg

For laboratory and research use only. Not for human or veterinary use, and not for diagnostic or therapeutic purposes.

Research material: Semax in every vial size (5mg–10mg)