Last updated: March 2026
Semax is a synthetic ACTH(4-10) heptapeptide developed at Russia's Institute of Molecular Genetics. It upregulates BDNF, NGF, and TrkB expression — enhancing focus, memory, and verbal fluency — and has been approved in Russia for stroke recovery and cognitive disorders since the 1990s.
Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is a synthetic peptide combining the ACTH(4-7) tetrapeptide — the behaviorally active core of adrenocorticotropic hormone — with a C-terminal Pro-Gly-Pro tripeptide that stabilizes it against enzymatic degradation. Unlike full ACTH, it lacks the adrenal-stimulating domain, so its effects are concentrated on neurotrophin modulation and neuroprotection.
Derived from the behaviorally active fragment of adrenocorticotropic hormone. The Met-Glu-His-Phe core (ACTH 4-7) drives cognitive effects. Pro-Gly-Pro extension prevents rapid degradation by proline endopeptidase — extending duration of action significantly.
A single dose produces 1.4× BDNF protein increase and 1.6× TrkB (BDNF receptor) phosphorylation. At the mRNA level: 3× BDNF and 2× NGF induction in hippocampus. This is the primary mechanism behind its nootropic and neuroprotective effects.
Improves cerebral microcirculation and has antithrombotic properties — documented in Ashmarin et al. (1995). This mechanism underlies its efficacy in acute ischemic stroke, where it is approved and used in Russian hospitals.
Modulates dopaminergic and serotonergic neurotransmission in the prefrontal cortex and limbic system. Enhances motivated attention and working memory without the dependence or withdrawal risk of stimulant medications.
Activates the MAP kinase cascade — documented by Ashmarin et al. (1995) — which drives neuronal growth, differentiation, and plasticity responses. Provides neuroprotection against ischemic damage and excitotoxicity.
The ACTH(4-10) fragment lacks the adrenal-stimulating domain present in full ACTH. At therapeutic doses, Semax does not significantly elevate cortisol, aldosterone, or other adrenal hormones — a major safety advantage.
Context: Semax has 30+ years of clinical use in Russia with a substantial published literature. The BDNF modulation data is well-replicated across multiple independent labs. Most large clinical trials are in Russian-language journals. Western regulatory review has not been pursued.
Semax is administered intranasally as a 0.1% or 1% solution. Intranasal delivery bypasses the blood-brain barrier limitations and provides direct CNS access via the olfactory epithelium — a key reason for the intranasal-only route.
Note: These are the dosing protocols studied in Russian clinical research. Individual response varies. This is not medical advice — consult a qualified physician before use. Semax is not FDA-approved.
| Protocol | Dose | Frequency | Duration | Tier |
|---|---|---|---|---|
| Entry / New User Assess tolerance first |
100–200 mcg | Once daily, morning | 1–2 weeks | Entry |
| Standard Cognitive Protocol Focus, memory, verbal fluency |
200–600 mcg | 1–2× daily (morning/midday) | 14–28 days on, 14 days off | Standard |
| Russian Clinical Protocol Cognitive disorder indication |
200–600 mcg (0.1%) | 2–3× daily | 14-day treatment courses | Clinical |
| Acute Stroke Protocol Hospital setting only |
Up to 3 mg/day | Multiple doses, hospital protocol | Short course, clinical supervision | Medical |
Because Semax and Selank engage overlapping neurotransmitter systems, experienced researchers typically rotate them sequentially rather than using both at once. The standard protocol runs three-week blocks of each compound separated by one-week breaks, creating an 8-week repeatable cycle. For the full table and alternative 2-week rotation schedule, see the Selank research page.
The NA variant — N-Acetyl Semax Amidate — is metabolically stabilized for improved mucosal absorption. Users consistently report it as a "cleaner" cognitive boost compared to standard Semax: the same focus and verbal fluency improvements, but with less of the stimulatory edge that some people find uncomfortable at higher doses. Dose accordingly — start 30–50% lower than your standard Semax dose and titrate up. NA-Semax is more expensive per vial but delivers more per dose.
Overall Assessment: Semax has a favorable safety profile with 30+ years of clinical use in Russia. Serious adverse events are rare. Most effects are mild and transient. The absence of adrenal stimulation at therapeutic doses is a key advantage over full ACTH.
Both are Russian heptapeptides with Pro-Gly-Pro stabilization developed at the same institute — but they operate through different mechanisms and serve complementary roles. They are frequently stacked together.
The combination is popular in Russian peptide circles and among Western biohackers for good reason: Semax provides the cognitive edge (BDNF, focus, memory) while Selank removes the anxiety interference that often accompanies intense cognitive work. Together they produce a "sharp but calm" state — motivated attention without the edge of stimulants. Both use intranasal delivery, can be taken concurrently, and have no known pharmacokinetic interactions. A common stack: Semax in the morning for cognitive drive, Selank as needed for anxiety management or before high-stakes social/work events.
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Semax is NOT FDA approved in the United States. It is approved in Russia and Ukraine for acute ischemic stroke, cognitive impairment, and peptic ulcers. This page is for educational and research purposes only — it is not medical advice, and does not constitute a recommendation to use Semax. Individual results vary. Always consult a qualified healthcare provider before starting any peptide or nootropic protocol. 🇷🇺 Approved Russia/Ukraine Research Compound (US/EU)