Semax
ACTH(4-10) analog · N-acetyl Semax
Heptapeptide ACTH(4-10) analog without corticotropic activity
Overview
Semax is a synthetic heptapeptide based on the 4–10 fragment of adrenocorticotropic hormone (ACTH), modified so that it retains neuromodulatory activity while lacking the hormonal (corticotropic) effects of the parent molecule. It was developed in Russia and is used there for indications spanning stroke recovery, cognitive complaints, and optic-nerve disorders, most commonly as intranasal drops or spray.
Reported effects include enhanced attention, memory, and stress resilience, with neuroprotective and BDNF-modulating actions described in preclinical work. As with Selank, the bulk of the evidence base is Russian-language clinical and laboratory research rather than large Western regulatory trials. The N-acetyl variant is a commonly encountered, reportedly more stable form.
Pharmacokinetic and dose-response data in peer-reviewed Western sources are limited, so the dosing summarized here reflects widely-reported community and clinical practice and should be treated as a research reference rather than a validated protocol.
Key parameters
- Dose range
- 200–600 mcg per dose (community)
- Frequency
- 1–2× daily
- Half-life
- Very short in plasma (minutes); central effects outlast it
- Route
- Intranasal
- Vial sizes
- 5 mg · 10 mg
- Regulatory status
- Used clinically in Russia (registered there for stroke, cognitive, and related indications); not approved by the FDA, EMA, or other Western regulators. Material supplied outside Russia is labeled for laboratory and research use only.
Mechanism of action
BDNF / neurotrophic upregulation
Reported to increase expression of brain-derived neurotrophic factor (BDNF) and related neurotrophins, proposed to underlie its neuroprotective and cognitive effects.
Dopaminergic / monoaminergic modulation
Described to modulate dopaminergic and other monoaminergic systems, consistent with reported effects on attention, motivation, and alertness.
Melanocortin-related signaling (non-hormonal)
Derived from the ACTH(4-10) sequence, Semax engages melanocortin-related neuromodulatory pathways while lacking the steroidogenic activity of intact ACTH.
Dosing protocol & phases
| Phase | Weeks | Dose | Notes |
|---|---|---|---|
| Standard (community) | Ongoing course | 200–600 mcg per dose intranasally, 1–2× daily | Often split between nostrils; community-derived, not a regulatory schedule. Higher concentrations (e.g. 1%) are used in some Russian clinical contexts. |
| Course duration | ~10–14 days (clinical use) | As above, then reassess | Russian clinical protocols are often short and course-based rather than continuous. |
Reconstitution calculator
Pre-filled with Semax's vial sizes. Adjust the water volume and target dose to see the exact draw, with warnings for doses that are hard to measure or won't fit a syringe.
At 2,500 micrograms per millilitre, a 250 microgram dose is 0.1 millilitres, or 10 units on a U-100 syringe, giving 20 doses per vial.
Supplies needed
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Recommended supply
Semax — research vial
From our verified partner Dynotides, with a third-party certificate of analysis per batch.
Injection supplies
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Bacteriostatic water
Diluent for reconstituting lyophilized vials.
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Insulin syringes (U-100)
0.3–0.5 mL, 29–31 G for accurate small draws.
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Alcohol prep pads
Sterile swabs for the vial stopper and site.
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Sharps container
Safe disposal of used needles.
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Storage fridge
Keeps reconstituted vials at 2–8 °C.
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Insulated travel case
Cooled, TSA-friendly case for travel.
Missed-dose guidance
As a short-acting intranasal peptide, a missed dose is generally skipped and the normal schedule resumed at the next administration rather than doubled. No approved-label guidance exists.
Side effects & safety
| Category | Effect | Trial incidence |
|---|---|---|
| General | Generally reported as well toleratedRussian literature reports a favorable tolerability profile; quantified Western incidence data are not available. | — |
| Nasal / local | Nasal irritation or mild congestionAssociated with intranasal administration generally rather than the peptide specifically. | — |
| Neurological | Headache or overstimulation at higher doses | — |
Clinical trials & evidence
Russian ischemic stroke studies
Clinical (Russia)Typically 10–14 days · Adults with acute ischemic stroke
Reported neuroprotective benefit and faster neurological recovery when used adjunctively; results come from Russian-language literature not indexed with ClinicalTrials.gov identifiers.
Trial identifier needs verification
Preclinical neuroprotection studies
Preclinical (animal)Varies · Rodent models
Neuroprotective, nootropic, and BDNF/NGF-upregulating effects described, including in models of cerebral ischemia.
Trial identifier needs verification
Storage & handling
- Lyophilized
- Refrigerate lyophilized powder at 2–8 °C, protected from light; for long-term storage a freezer (around −20 °C) is preferred.
- Reconstituted
- Once dissolved into a nasal solution, refrigerate at 2–8 °C and use within a few weeks; do not freeze.
Comparisons
| Vs. | Target | Half-life | Dosing | Efficacy | Status |
|---|---|---|---|---|---|
| Selank | ACTH(4-10)-related vs tuftsin/enkephalin-related | Short (both) | Intranasal (both) | More stimulating/nootropic-leaning vs more anxiolytic-leaning (reported) | Neither FDA-approved (used in Russia) |
Featured in these stacks
Russian Nootropic (Selank + Semax)
Selank and Semax are short peptides developed in Russia, where they are used clinically as nasal sprays. Selank is derived from tuftsin and associated with anxiolytic effects; Semax is an ACTH(4-10) fragment associated with focus and neuroprotection. Stacking them aims to pair calm (Selank) with drive/focus (Semax).
Sources & references
- [1]Medvedeva EV et al. The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain. Mol Biol 2014 (Semax neuroprotection/BDNF mechanisms). ↗ source
- [2]Gusev EI, Skvortsova VI et al. Semax in the treatment of acute ischemic stroke — Russian clinical literature. ↗ source
Frequently asked questions
Does Semax have hormonal effects like ACTH?
It is derived from the ACTH(4-10) fragment but is modified to retain neuromodulatory activity without the corticotropic (steroid-stimulating) effects of intact ACTH. It is generally used intranasally.
What is N-acetyl Semax?
N-acetyl Semax is an acetylated form of the peptide that is reported to be more stable and longer-acting; it is commonly encountered in community use, sometimes combined with amidated variants. Head-to-head pharmacokinetic comparisons in peer-reviewed Western sources are limited.
Related protocols
Selank
TP-7
Heptapeptide anxiolytic developed from the immunopeptide tuftsin
Pinealon
EDR peptide
Tripeptide (Glu-Asp-Arg) studied for neuronal oxidative-stress protection (preclinical/Russian clinical)
Looking to match this protocol to a verified research vial? Our partner supplier publishes a certificate of analysis per batch.
For educational and research reference only. Not intended for human consumption, not medical advice. Compounds discussed are sold and used for laboratory research purposes only.