Semax

What Is Semax?

Semax is a synthetic peptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, built from a small fragment of adrenocorticotropic hormone (ACTH), the hormone that normally triggers the adrenal glands to release cortisol during stress. Semax uses only the portion of ACTH tied to nervous system effects, with a modification that removes the cortisol-triggering activity entirely.

That distinction matters: Semax was specifically engineered to retain ACTH's effects on the brain while eliminating its hormonal action on the adrenal glands. It's been used clinically in Russia since the 1990s, primarily for ischemic stroke recovery and other neurological conditions, based on decades of Russian clinical research.

What Semax Is Being Researched For

• Stroke Recovery

  The most established area of Semax research addresses acute ischemic stroke. An early clinical and electrophysiological study found that adding Semax to standard stroke treatment influenced the rate of neurological recovery compared to conventional therapy alone.^[1]

• Neurotrophic Factor Production

  A separate line of research examined how Semax affects brain-derived neurotrophic factor (BDNF), a protein involved in neuron survival and plasticity, finding that Semax specifically binds and increases BDNF levels in animal models.^[2]

• Longer-Term Stroke Rehabilitation

  Building on the earlier acute-stroke research, a more recent open clinical study examined Semax across both acute and recovery phases of ischemic stroke, tracking motor function, daily living measures, and plasma BDNF over several months.^[3]

How Semax Works

• Increasing BDNF Without Triggering Cortisol

  Research points to Semax binding specifically to sites associated with brain-derived neurotrophic factor and increasing its levels in relevant brain regions, while lacking the hormonal activity that would normally cause the adrenal glands to release cortisol.^[2]

• Supporting Neurological Recovery After Stroke

  Research points to Semax's addition to standard stroke care being associated with improved recovery of neurological function, tracked using clinical rating scales alongside EEG and evoked-potential recordings in early studies.^[1][3]

• A Modified Fragment, Not the Full Hormone

  Research points to Semax's structure retaining just the neurologically active portion of ACTH, with an added stabilizing sequence that resists rapid breakdown, allowing sustained activity without the broader hormonal effects of the intact molecule.

Reconstitution and Handling

Semax is typically supplied as a lyophilized powder in a sealed vial and reconstituted with bacteriostatic water before use in a research setting. Water should be added slowly rather than injected directly into the powder, and the vial should be swirled, not shaken.

Since the amount of water used affects the concentration of the final solution, researchers often use a dosage calculator to work this out before mixing. Once reconstituted, the solution is kept refrigerated to help preserve its stability.

Key Takeaways

Semax stands out for its decades-long clinical use in Russia, where it's an approved medication for stroke recovery backed by real human trial data, even though it hasn't been evaluated or approved in the US. Its mechanism centers on increasing BDNF specifically without the broader hormonal effects of full ACTH, a distinction that's core to why it was developed the way it was. As with Selank, the evidence base is substantial but concentrated in Russian-language literature, worth factoring in alongside the clinical history.

Frequently Asked Questions

Sources and Research

1. Gusev EI, Skvortsova VI, Miasoedov NF, et al. Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study). Zh Nevrol Psikhiatr Im S S Korsakova. 1997;97(6):26-34.
2. Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of adrenocorticotropin(4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain. J Neurochem. 2006;97(Suppl 1):82-86.
3. Gusev EI, Martynov MY, Kostenko EV, et al. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(4):61-68.