Semax: A Laboratory Research Reference

Semax is a synthetic heptapeptide modelled on a fragment of adrenocorticotropic hormone (ACTH). It is studied in laboratory research for its neuroprotective and cognition-related effects in experimental models.

This page is a non-promotional scientific reference for researchers. It summarises the chemical identity, molecular characteristics, mechanism as described in the literature, research areas, and analytical testing of semax. It does not provide dosing, therapeutic, or human-use guidance of any kind. Semax supplied by Bulk Aussie Peptides is for laboratory research purposes only.

What Is Semax?

Semax is a synthetic heptapeptide derived from the ACTH(4–7) region of adrenocorticotropic hormone, a fragment that retains no corticotropic activity of its own. A defining feature of the design is the addition of a Pro-Gly-Pro sequence to the carboxy terminus, a modification intended to protect the peptide from rapid enzymatic degradation. Semax is conventionally written Met-Glu-His-Phe-Pro-Gly-Pro.

For background on how synthetic research peptides are produced and verified, see the synthetic peptides research guide.

Molecular Characteristics

Several molecular properties are used to identify semax in analytical documentation:

• Classification: a synthetic ACTH-fragment-derived heptapeptide, classed among nootropic research peptides.
• Sequence: Met-Glu-His-Phe-Pro-Gly-Pro, incorporating a carboxy-terminal Pro-Gly-Pro motif.
• Molecular weight: reported in Daltons (Da) on product documentation; the measured value on a Certificate of Analysis should be compared against the theoretical mass derived from the sequence.
• Physical form: supplied as a lyophilised (freeze-dried) powder, the standard presentation for research peptides.

How Semax Works

Semax is studied for effects described as neuroprotective. Research reports that semax is associated with upregulation of the neurotrophins brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), and it has been investigated in models of cerebral ischaemia. Its relationship to ACTH fragments distinguishes it from peptides of unrelated parent structure.

These observations are preclinical and describe peptide activity in model systems; they do not constitute a therapeutic use.

Areas of Scientific Research

The research literature describes several lines of investigation involving semax:

• Neuroprotection: studies in ischaemia and neural-stress models.
• Neurotrophin signalling: investigation of BDNF and NGF upregulation.
• Functional imaging: work examining resting-state connectivity changes associated with the peptide.

These investigations are conducted in vitro or in approved animal research models under institutional oversight. They do not translate to approved human use.

Analytical Testing

As with other research peptides, semax is characterised using:

• HPLC for purity assessment, reported as a percentage of total peak area.
• Mass spectrometry for identity confirmation, by comparing measured molecular mass to the theoretical value.

Guidance on interpreting the resulting documents is available in the article on how to read a peptide Certificate of Analysis.

Storage and Handling

In a laboratory context, lyophilised semax is typically stored in a freezer, protected from light and moisture, and handled according to the product-specific documentation. Once reconstituted, the resulting solution is refrigerated and used within the timeframe stated in the documentation. General guidance is covered in the peptide storage and stability reference.

Frequently Asked Questions

• What is semax? Semax is a synthetic heptapeptide derived from an ACTH fragment.
• What is the semax sequence? It is conventionally written Met-Glu-His-Phe-Pro-Gly-Pro.
• What is semax studied for? It is investigated in laboratory models for neuroprotection and neurotrophin signalling.
• Is semax the same as selank? No — both are ACTH-related heptapeptides with the Pro-Gly-Pro extension, but they are distinct sequences with different parents (ACTH versus tuftsin).
• How is semax purity tested? Purity is commonly estimated by HPLC, while identity is confirmed by mass spectrometry.

References

• Ashmarin, I. P., Nezavibatko, V. N., Myasoedov, N. F., et al. (1997). A nootropic adrenocorticotropin analog 4-10 fragment with enhanced stability. Neuroscience and Behavioral Physiology.
• Medvedeva, E. V., Dmitrieva, V. G., Limborska, S. A., et al. (2020). Functional connectomic approach to studying selank and semax effects. PubMed 32342318 — a resting-state functional-imaging comparison of the two peptides.

Related Research Resources

• Selank: A Laboratory Research Reference — a related ACTH-fragment-derived heptapeptide.
• Synthetic Peptides: Research Guide — how research peptides are produced and verified.
• DSIP: A Laboratory Research Reference — a peptide studied in sleep-related research.