Semax the science.

Semax is a synthetic peptide based on the 4–10 fragment of ACTH (adrenocorticotropic hormone), with a Pro-Gly-Pro tail added to slow its breakdown. The parent ACTH fragment was long studied for behavioral and memory-related effects that are separate from ACTH’s hormonal role, and Semax was designed as a more stable research analog of that activity.

It was developed at Russian research institutes and has been studied in both animals and humans there. Semax is not approved by the FDA and is supplied here strictly for research use.

Semax research has examined several connected mechanisms:

• Neurotrophic signaling — effects on brain-derived neurotrophic factor (BDNF) and related neurotrophin pathways in animal models.
• Neuroprotection — responses in models of ischemic and oxidative stress to the brain.
• Neuromodulation — exploratory work on receptor- and gene-expression-level effects, including studies of opioid- and inflammation-related pathways.

Semax has been studied in animal models and some human studies, much of it from Russian research groups:

• Ischemic-stroke research (2018). A clinical study published in a Russian neurology and psychiatry journal examined Semax in patients at different stages of ischemic stroke.
• Anti-inflammatory signaling (2023). A study in F1000Research examined the effect of the ACTH(4-10) Pro-Gly-Pro analog on anti-inflammatory cytokine expression.
• Receptor-level mechanism (2025). Work in the British Journal of Pharmacology reported that the Semax peptide targets the μ-opioid receptor gene Oprm1 in laboratory models.

These are findings in animals plus some human studies; broad human therapeutic use is not established outside its original research context.

The Semax evidence base combines animal models with some human studies, largely from Russian research. It is not FDA-approved, and no approved indication, dosing, or therapeutic claim applies in the United States. Semax is supplied strictly as a research material for laboratory investigation.