Semax
Semax (Synthetic ACTH 4-10 Analog)
Also known as: SEMAX, Heptapeptide SEMAX
Prompted by Jack Butcher (Visualize Value) · AI-authored by Claude · Research-sourced
A synthetic ACTH fragment approved in Russia as a nootropic since 1994. Rapidly upregulates BDNF expression in the brain within 30 minutes of intranasal administration.
Quick Facts
Approved in Russia and Ukraine as a prescription nootropic. Not FDA-approved in the United States.
Overview
Semax is a synthetic heptapeptide analog of ACTH (adrenocorticotropic hormone) fragments 4-10, with an added Pro-Gly-Pro sequence at the C-terminus for enhanced stability. Developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in the 1980s, it has been used clinically in Russia since 1994.
Semax is classified as a nootropic and neuroprotective agent. It is prescribed in Russia for cognitive enhancement, stroke recovery, peptic ulcers, optic nerve disease, and as a treatment for attention disorders. It is administered intranasally and has a rapid onset of action.
Unlike many ACTH-derived peptides, Semax does not exhibit hormonal (corticotropic) activity — it does not stimulate the adrenal glands or increase cortisol levels. Its effects are mediated through neurotrophic factor modulation.
Mechanism of Action
Semax acts primarily through upregulation of brain-derived neurotrophic factor (BDNF) and its receptor TrkB. BDNF is critical for neuronal survival, synaptic plasticity, and memory formation. Studies show Semax increases BDNF mRNA expression in the hippocampus and cortex.
It also modulates nerve growth factor (NGF) and neurotrophin-3 (NT-3) expression, supporting broader neurotrophic signaling. This multi-target neurotrophic approach distinguishes Semax from single-pathway nootropics.
Semax influences the serotonergic and dopaminergic systems. It modulates dopamine and serotonin metabolism in brain structures including the striatum and hippocampus, which may underlie its effects on mood, motivation, and attention.
Additionally, Semax has demonstrated anti-inflammatory effects in the CNS by modulating expression of inflammatory cytokines and chemokines. In stroke models, it reduces the inflammatory cascade that causes secondary brain damage after ischemia.
Research Summary
Clinical research on Semax comes predominantly from Russian medical literature. In Russian clinical practice, it has demonstrated efficacy for cognitive enhancement in healthy individuals, with improvements in attention, memory, and mental stamina.
Stroke research is perhaps the most robust area. Clinical studies in ischemic stroke patients show improved neurological outcomes, reduced infarct volume, and accelerated recovery when Semax is administered acutely. A study of 100 stroke patients showed significant improvement in NIHSS scores.
BDNF research demonstrates that a single intranasal dose of Semax significantly increases BDNF mRNA expression within 30 minutes, with peak effects at 3–6 hours and sustained elevation for up to 24 hours.
Animal research shows neuroprotective effects in models of Parkinson's disease, Alzheimer's disease, and traumatic brain injury. Cognitive enhancement studies in rodents demonstrate improved spatial memory, object recognition, and learning speed.
Limitations: Most clinical data comes from Russian studies, many of which are not indexed in Western databases. Large-scale, placebo-controlled trials meeting Western regulatory standards have not been conducted.
Key References
Semax, an ACTH(4-10) analogue with nootropic properties, activates dopaminergic and serotoninergic brain systems
Eremin KO, et al. · Neurochemical Research (2005) · 10.1007/s11064-005-6967-x
Demonstrated that Semax modulates dopamine and serotonin metabolism in the striatum and hippocampus, providing a neurochemical basis for its cognitive effects.
Regulatory peptide semax stimulates the expression of BDNF and its receptors in brain
Dolotov OV, et al. · Doklady Biological Sciences (2006) · 10.1134/S0012496606010145
Showed that a single Semax administration significantly upregulates BDNF and TrkB receptor expression in the hippocampus and basal forebrain within hours.
Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia
Medvedeva EV, et al. · Cellular and Molecular Neurobiology (2017) · 10.1007/s10571-016-0466-0
In a cerebral ischemia model, Semax activated expression of BDNF, NGF, NT-3, and their receptors, demonstrating a multi-target neuroprotective mechanism.
Neuroprotective effect of semax in global cerebral ischemia
Gusev EI, et al. · Neuroscience and Behavioral Physiology (2006) · 10.1007/s11055-006-0076-0
Clinical study showing Semax administration in acute ischemic stroke improved neurological outcomes and reduced neural tissue damage compared to standard treatment alone.
Protocols
Cognitive enhancement
Standard 0.1% solution delivers ~50 mcg per drop. Start with lower doses. Best used in the morning and afternoon — avoid evening dosing due to stimulating effects.
Neuroprotection / stroke recovery (clinical)
Higher-concentration 1% solution used in clinical settings. Administered under medical supervision in Russian clinical protocols.
Side Effects & Safety
| Frequency | Effect |
|---|---|
| common | Nasal irritation Mild burning or tingling upon intranasal administration. Usually transient. |
| uncommon | Headache Occasionally reported, particularly at higher doses. |
| rare | Dizziness |
| uncommon | Insomnia More likely with late-afternoon or evening dosing due to stimulating effects. |
Contraindications
- —Known hypersensitivity to ACTH-related peptides
- —Acute psychosis or severe anxiety disorders (stimulating effects may exacerbate)
- —Pregnancy or breastfeeding (insufficient safety data)
Reconstitution & Storage
Related Peptides
Often used alongside Selank, which provides complementary anxiolytic effects. Semax enhances focus and cognition while Selank reduces anxiety — the combination addresses both cognitive performance and emotional resilience.