What Is Semax? A Research Overview

Semax is a synthetic heptapeptide analogue of the adrenocorticotropic hormone fragment ACTH(4–10), studied in preclinical and in-vitro models as a neuropeptide research compound — most notably for its effects on brain-derived neurotrophic factor (BDNF) signaling and neuroprotection. It is supplied strictly for research use only and is not approved for human or veterinary use.

Quick facts

• Class: synthetic ACTH(4–10) analogue / heptapeptide (Met–Glu–His–Phe–Pro–Gly–Pro)
• Research focus: neuropeptide, BDNF/NGF modulation, and cognition-related research in animal and cell models
• Form: lyophilized powder, ≥99% HPLC purity, third-party tested, USA-lyophilized

What is Semax?

Semax is a short synthetic peptide derived from the 4–10 region of adrenocorticotropic hormone (ACTH), with a C-terminal Pro–Gly–Pro tripeptide added to improve stability against enzymatic breakdown. Unlike the parent ACTH fragment, Semax is reported to lack hormonal (corticotropic) activity while retaining neurotropic properties in laboratory models. Researchers categorize it as a regulatory neuropeptide and study it as a tool compound rather than a hormone.

What does the research show?

Published research on Semax is preclinical, conducted in rodents and cultured cells. In one in-vivo study, the heptapeptide was reported to stimulate BDNF expression across several regions of the rat brain (Dolotov et al., 2003). In rat models of cerebral ischemia–reperfusion, genome-wide and proteomic analyses have associated Semax administration with changes in the expression of genes and proteins linked to the immune and vascular systems and to neuronal survival (Medvedeva et al., 2014; Sudarkina et al., 2021). These findings describe responses observed in animals and cell cultures, not outcomes in humans.

Mechanisms studied in the lab

• Neurotrophin modulation: reported upregulation of BDNF and nerve growth factor (NGF) and related receptor signaling in rat brain tissue.
• Neuroprotection in injury models: changes in survival-related gene and protein expression in rodent cerebral ischemia–reperfusion models.
• Vascular and immune signaling: altered expression of genes tied to vascular and immune pathways in focal ischemia models.

Research status and safety

Semax is not approved by the FDA for any human or veterinary use. The evidence base is preclinical, and effects observed in animals or cell cultures do not establish safety or efficacy in people. It is offered solely as a research material for qualified investigators and must not be administered to humans or animals.

Handling

Semax ships as a lyophilized powder and should be stored cold and protected from light and moisture until use. For preparation, see our guide on how to reconstitute a research peptide, and browse related cognitive research peptides. To view specifications and availability, see Semax — ≥99% pure, third-party tested.

FAQ

How does Semax differ from Selank?

Both are short synthetic peptides studied as neuropeptide research compounds, but they have different origins. Semax is an analogue of the ACTH(4–10) fragment and is investigated mainly for neurotrophic and cognition-related endpoints (e.g., BDNF). Selank is a synthetic analogue of the immune peptide tuftsin and is studied more for anxiolytic and immunomodulatory endpoints. Read about Selank.

Is Semax a drug or supplement?

Neither. In the United States it is an unapproved research chemical for laboratory use only — not a dietary supplement and not an FDA-approved medication.

References

1. Dolotov OV, et al. The heptapeptide SEMAX stimulates BDNF expression in different areas of the rat brain in vivo. Dokl Biol Sci. 2003.
2. Medvedeva EV, et al. The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia. BMC Genomics. 2014.
3. Sudarkina OY, et al. Brain Protein Expression Profile Confirms the Protective Effect of the Semax Peptide in Rat Cerebral Ischemia–Reperfusion. Int J Mol Sci. 2021.

For research use only. Not for human or veterinary use. Statements have not been evaluated by the FDA.