Educational reference only. Informational material drawn from peer-reviewed literature. Not medical advice and not a recommendation to use, dose, or modify any therapy. Decisions about hormone therapy should be made with a qualified healthcare provider.
Overview
Overview
Semax is a synthetic heptapeptide (7 amino acids) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, the same institute that produced Selank. Where Selank was derived from tuftsin and acts on anxiety pathways, Semax is a synthetic analog of ACTH(4-10) (the 4-10 region of adrenocorticotropic hormone), modified with a Pro-Gly-Pro C-terminal extension (the same stability-enhancing motif used in Selank's design). This shared design pattern reflects the Russian neuropeptide development tradition, but the two compounds target entirely different neurological systems.
The crucial design feature: while Semax retains the CNS effects of ACTH(4-10) (neurotrophic effects, cognitive enhancement, neuroprotection), the hormonal activity has been specifically engineered out. Semax does NOT stimulate the adrenal cortex, does NOT raise cortisol, and does NOT activate the HPA stress axis. This is a fundamentally different compound from full-length ACTH despite the structural relationship.
Semax has been approved in Russia since 1996 and in Ukraine for clinical use as a nootropic and neuroprotective agent. It is registered for ischemic stroke (acute and recovery phases), cognitive impairment (various etiologies), optic nerve atrophy, and other neurological indications. The standard formulation is an intranasal nasal spray (matching the Selank pattern). Direct nose-to-brain delivery makes Semax practical and effective despite being a peptide.
FDA 503A review status: The FDA is currently reviewing Semax for inclusion on the 503A Bulks List (compounding pharmacy supply) with a decision scheduled for July 2026. The indications under FDA evaluation are cerebral ischemia, migraine, and trigeminal neuralgia. This represents the first serious US regulatory engagement with Semax in its 30+ year history.
Forms
Available forms & half-lives
| Form | Approximate half-life |
|---|---|
| Intranasal Semax (Russian-approved nasal spray) | Rapid plasma clearance; sustained CNS effects via tissue retention or downstream neurotrophic cascades |
| Subcutaneous Semax (research use) | Similar rapid clearance |
What it does
Main effects
- Acute ischemic stroke recovery: Russian-approved indication; multi-pathway neuroprotection of penumbra, anti-inflammatory effects, VEGF-mediated angiogenesis support; reduced mortality and improved functional outcomes in some Russian clinical studies
- Cognitive impairment of various etiologies (post-stroke, vascular, age-related): Russian-approved; BDNF/TrkB-mediated cognitive enhancement
- Optic nerve atrophy: Russian-approved indication; improvements in visual function documented
- BDNF/TrkB neurotrophic system upregulation: 1.4-fold BDNF protein increase, 1.6-fold TrkB phosphorylation, 3-fold exon III BDNF mRNA, 2-fold TrkB mRNA in rat hippocampus with single dose (Dolotov et al. 2006)
- NGF upregulation: supports cholinergic neurons relevant to cognitive function
- No hormonal activity. Despite ACTH origin, does NOT stimulate adrenal cortex, raise cortisol, or activate HPA stress axis; this was a deliberate design achievement
- Multi-target mechanism: neurotrophic, dopaminergic, serotonergic, cholinergic enhancement, neuroinflammation suppression, VEGF modulation, residual melanocortin receptor effects
- Intranasal direct nose-to-brain delivery: bypasses BBB limitations via olfactory and trigeminal pathways
- Cognitive enhancement (off-label): focus, memory, productivity reports; nootropic use
- Migraine and trigeminal neuralgia: under active FDA 503A review
What to watch for
Common side effects
- Generally clean safety profile based on ~30 years of Russian clinical use (since 1996)
- Notably ABSENT: no sedation, no cognitive impairment, no dependence, no withdrawal, no abuse potential, no HPA axis effects, no cortisol elevation, no adrenal stimulation (engineered out)
- Nasal irritation from intranasal administration: mild
- Mild headache: occasional
- Mild dizziness: rare
- Sleep disturbance: Semax is generally activating, so exposure close to bedtime can disturb sleep
- Mild GI symptoms: rare
- Anxiety/restlessness: rare, usually with high doses
- Mild stimulating effects: improved focus, energy, mood lift (generally desired)
- Rare allergic reactions: possible with any peptide
- Pregnancy and lactation safety unestablished: conservative approach to avoid use
- Few drug interactions: no CYP-mediated metabolism; possible synergy with cholinesterase inhibitors; potentially additive with stimulants
- Russian/Ukrainian approval doesn't translate automatically to Western pharmaceutical standards
- FDA 503A review pending (July 2026 decision): outcome will affect US legal access
- Not currently WADA-prohibited (verify before use in tested sport)
Key facts
Key facts worth knowing
- Semax is a synthetic heptapeptide with sequence Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP). The first four amino acids (Met-Glu-His-Phe) correspond to ACTH(4-7), the biologically active core of the ACTH(4-10) fragment. The added Pro-Gly-Pro C-terminal tail provides metabolic stability and resistance to aminopeptidases.
- Approved in Russia since 1996. One of the longest-standing peptide approvals from the Russian neuropeptide tradition. Also approved in Ukraine and some CIS countries. ~30 years of clinical use.
- No hormonal activity. Despite the ACTH origin, Semax does not stimulate adrenal cortex, does not raise cortisol, and has no HPA axis activity. The cognitive/neuroprotective effects of ACTH(4-10) were preserved while the hormonal effects were engineered out by replacing the C-terminal Arg-Trp-Gly with Pro-Gly-Pro. This is a meaningful pharmaceutical design achievement.
- Primary mechanism is BDNF/TrkB upregulation. Dolotov et al. 2006 demonstrated 1.4-fold BDNF protein increase, 1.6-fold TrkB phosphorylation, 3-fold exon III BDNF mRNA, 2-fold TrkB mRNA in rat hippocampus with single Semax dose. Also affects NGF, dopaminergic, serotonergic, cholinergic, VEGF, and neuroinflammatory systems. Dolotov OV et al., Brain Research 2006
- Substantial Russian clinical evidence base for stroke applications and cognitive function. Standard intranasal administration provides direct nose-to-brain delivery via olfactory and trigeminal pathways (more efficient than systemic administration for CNS effects).
- Same Institute of Molecular Genetics origin as Selank. Companion compounds in the Russian neuropeptide tradition, frequently discussed and used together. Both use the Pro-Gly-Pro stability extension and intranasal administration but target different neurological systems (Semax for stroke/cognitive, Selank for anxiety).
- FDA 503A review pending with decision scheduled for July 2026. Indications under evaluation: cerebral ischemia, migraine, and trigeminal neuralgia. This represents the first serious US regulatory engagement with Semax in its 30+ year history. If approved for 503A inclusion, US compounding pharmacies would be able to legally compound Semax for these indications.
- Generally clean safety profile. Limited adverse effects in clinical use over ~30 years. WADA status: Not currently on the WADA Prohibited List (verify current status before use in tested sport).
Legal status
Legal status
Approved in Russia (since 1996) and Ukraine for stroke, cognitive impairment, and optic nerve indications. Under FDA 503A review with decision scheduled for July 2026 for cerebral ischemia, migraine, and trigeminal neuralgia. Not currently FDA-approved. Available through unregulated sources and limited compounding (with evolving regulatory status). Not a controlled substance. Not currently WADA-prohibited.