Semax

What it is

Semax is a seven-amino-acid peptide developed in Russia in the 1980s. It combines a fragment of adrenocorticotropic hormone (ACTH 4-7) with a Pro-Gly-Pro tail that slows its breakdown. It has no hormonal effect on the adrenal glands.

How it works

Animal studies show it raises brain-derived neurotrophic factor (BDNF) and its receptor, and influences dopamine and serotonin systems. It is usually given as a nasal spray in the countries where it is registered.

What the research shows

• Russian clinical studies report use after ischemic stroke and for cognitive impairment, though most trials are small and not widely replicated in Western literature.
• Rodent studies show improved learning and neuroprotection after injury.

Regulatory status

Registered as a medicine in Russia and some neighboring countries. Not FDA-approved. In July 2026 the FDA's Pharmacy Compounding Advisory Committee voted to recommend Semax for the compounding bulks list. On October 28, 2026, the Department of Health and Human Services announced an interim enforcement discretion policy covering Semax and five other peptides: it does not intend to take action against state-licensed pharmacies, federal facilities or licensed physicians that compound them under section 503A, as long as strict conditions are met. These include bulk material from an FDA-registered manufacturer with a certificate of analysis, a single active ingredient, only the routes of administration the policy lists, specific labeling and reporting of serious adverse events to the FDA. The policy does not add Semax to the 503A bulks list or approve any product, it does not cover 503B outsourcing facilities, and HHS says it may revisit the policy if safety or quality problems arise. Research-grade material is not a compounded drug product.

Storage and handling

Lyophilized (freeze-dried) powder is most stable sealed, dry and protected from light. Laboratory practice is to keep unopened vials frozen at about -20 °C for long-term storage, or refrigerated at 2 to 8 °C for shorter periods. After reconstitution, keep the solution refrigerated at 2 to 8 °C, avoid repeated freeze-thaw cycles and use aseptic technique for every draw. Formal stability data in solution has not been published for most research peptides, so follow the supplier's label and certificate of analysis.

Reconstitution math

To work out concentration, volume and U-100 syringe units for any vial size, use the reconstitution calculator with Semax selected. Always confirm the vial content against the label and the batch's certificate of analysis.

Key references

• Dolotov OV et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res. 2006.
• Search PubMed for Semax studies

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