Semax Dosage Guide: Reported Ranges, Half-Life & Reconstitution

Semax at a glance

What it is

Semax, the synthetic heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro — an ACTH(4-7) fragment extended with a Pro-Gly-Pro tail that slows enzymatic breakdown. It carries no corticotropic activity.

Researched for

Ischaemic stroke and cognitive/attention research, almost entirely within a Russian research tradition; the English-indexed literature is dominated by rat brain-ischaemia gene-expression work.

Commonly reported range

Community figures cluster around 300-600 mcg per administration; the registered Russian product is a 0.1% or 1% intranasal drop, dosed in drops rather than by weight.

Route reported

The registered product and most published research use the intranasal route. Subcutaneous injection is a community practice with no registered product behind it.

Reported frequency

Community reports describe once or twice daily in short courses; the Russian clinical protocols are also short-course.

Mechanism

An ACTH fragment lacking corticotropic activity; associated in animal work with BDNF/neurotrophin signalling and with broad changes in ischaemia-related gene expression.

Plasma half-life

Minutes. The Pro-Gly-Pro tail slows degradation relative to the bare ACTH fragment but does not make it long-lived.

Regulatory status

Registered as a medicine in Russia; not FDA-approved and not approved anywhere in the EU or US. Research/educational use only.

Reported ranges from research/community — examples, not recommendations.

What it is / mechanism

Semax is a synthetic analogue of the ACTH(4-10) region — specifically the ACTH(4-7) fragment Met-Glu-His-Phe, extended with Pro-Gly-Pro. The tail is the design feature: the bare fragment is degraded almost immediately by plasma and tissue peptidases, and the added tripeptide slows that enough for the molecule to be administered practically. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, and the whole compound is best understood as a stabilised piece of a hormone rather than a novel molecule. The important pharmacological point is what it does not do. ACTH's defining action is stimulating cortisol release from the adrenal cortex, and that activity lives in a different part of the molecule. The 4-7 fragment retains the behavioural and neurotrophic activity historically attributed to ACTH fragments while carrying no corticotropic effect, which is precisely why the fragment was chosen. Semax is not a corticosteroid, does not raise cortisol as its mode of action, and should not be reasoned about as though it were an ACTH substitute. What it does at a molecular level is less cleanly established than the marketing suggests. The most frequently cited association is with brain-derived neurotrophic factor and its receptor TrkB, with animal work reporting increased BDNF expression in relevant brain regions after administration. Beyond that, the strongest and most reproducible body of evidence is transcriptomic rather than receptor-level: in rat models of focal cerebral ischaemia, Semax produces broad, measurable changes in gene expression — Medvedeva et al. (BMC Genomics, 2014; PMID 24661604) reported genome-wide transcriptional changes affecting immune and vascular system genes, and Dergunova et al. (2021; PMID 34097675) reported suppression of transcripts encoding proinflammatory mediators after reversible brain ischaemia. Sudarkina et al. (2021; PMID 34201112) reported a corresponding protein-expression profile. That is a real mechanistic literature, and it is worth reading it for what it is: consistent evidence that the compound changes ischaemia-related gene expression in rat brain. It is not a demonstration of a receptor, and it is not a human efficacy finding. A separate strand of interest concerns copper — Semax has been characterised as a copper-chelating peptide affecting copper-catalysed reactive oxygen species production in amyloid model systems — which is chemistry in artificial membrane models rather than a clinical mechanism.

Researched effects

The reported effects and the indexed evidence for them are two different things, and separating them is the most useful thing this section can do. What is reported: in Russian clinical and preclinical research Semax has been associated with improvements in attention, memory consolidation and mental fatigue, and it is registered in Russia for use in ischaemic stroke and transient ischaemic attack, as well as in ophthalmological indications involving the optic nerve. Those registrations are genuine — a national regulator did approve the product — and they rest on clinical work conducted largely in Russian-language journals over several decades. What is indexed in English: overwhelmingly animal work. A PubMed search for Semax returns rat brain-ischaemia transcriptomics, Alzheimer's-model animal studies, artificial-membrane copper chemistry, and a 2025 mouse spinal-cord-injury study reporting an effect on the mu opioid receptor gene Oprm1. Human work is sparse; Panikratova et al. (Doklady Biological Sciences, 2020; PMID 32342318) applied a functional connectomic approach to Selank and Semax effects, which is a human neuroimaging study but not an efficacy trial. The gap between those two paragraphs is the honest summary of Semax's evidence base. It is not that the clinical research does not exist; it is that most of it is not accessible to, or indexed by, the databases an English-speaking reader can check, and that the portion which is indexed is preclinical. A reader outside Russia is largely being asked to take the clinical case on trust. That is a materially different position from a compound whose trials can be looked up, and it is a reasonable thing to weigh — in either direction — rather than something to be quietly omitted. One further asymmetry is worth naming. The nootropic and mental-fatigue claims that dominate discussion of Semax outside Russia are not what the registered product is registered for. The registrations concern stroke and optic-nerve indications. Attention and cognition in healthy people is the use most people are actually interested in, and it is the use with the least behind it.

Dosage — reported ranges (overview)

The figures below are examples of what has been reported, not a recommendation, and the two sources of figures are not directly comparable. The registered Russian pharmaceutical product is an intranasal solution supplied at 0.1% or 1% concentration and dosed in drops per nostril rather than by microgram weight, in short courses. Converting a drop count into a microgram figure requires knowing the drop volume, and the resulting number is an estimate rather than a labelled dose — a 0.1% solution is 1 mg/mL, so a drop of roughly 0.05 mL carries about 50 mcg, but drop size varies with the dropper. Community sources discussing reconstituted research material describe amounts clustering around 300-600 mcg per administration, once or twice daily, usually in courses of one to several weeks rather than continuously. These figures are anecdotal. They are also frequently quoted without specifying route, which matters a great deal here, since intranasal and subcutaneous administration of the same microgram amount are not equivalent. The reconstitution table below uses 300 mcg and 600 mcg as arithmetic reference points within that community range, for the purpose of making the concentration math legible. No dose, route or frequency is recommended.

A printable protocol sheet with a reconstitution reference and an injection log comes with All-Access Lifetime.

Reconstitution — bac-water math

Semax is dosed in micrograms, so reconstitution is a concentration calculation where small errors matter. Add bacteriostatic water slowly down the vial wall and swirl rather than shake. Concentration in mcg/mL = total micrograms in the vial / mL of water, and one unit on a U-100 insulin syringe is always 0.01 mL. Worked example for a 10 mg (10,000 mcg) vial:

This is concentration math, not a dose recommendation.

Injection / administration basics

The registered product and most published research use the intranasal route, delivered as drops or a metered spray. That is not an incidental detail: the compound was developed and tested as an intranasal preparation, and the published pharmacology describes that route. Subcutaneous injection of reconstituted research powder is a community practice with no registered product behind it and little published characterisation. One practical consequence is that the same reconstituted solution can be used either way. A vial reconstituted with bacteriostatic water can be loaded into a metered nasal applicator, in which case the concentration determines the micrograms delivered per actuation rather than per syringe unit — the arithmetic is the same calculation with a different final step. The calculator on this page and the concentration table below cover the concentration part regardless of which route the reader is reasoning about. General handling concepts — sterile technique, recomputing concentration whenever the vial size changes, and working from your own label — are covered here as general information. The detailed workflow comes with All-Access Lifetime, which includes the printable protocol sheet and injection log for every compound. This is general educational information, not a personal administration protocol; a qualified professional should guide any actual use.

Half-life & frequency rationale

Semax is cleared from plasma very rapidly, on the order of minutes, despite the Pro-Gly-Pro stabilisation that protects it relative to the unmodified ACTH(4-7) fragment. The stabilising tail buys enough time for the molecule to be administered practically; it does not produce a long-lived compound, and no reading of the pharmacokinetics supports the idea of a sustained blood level between administrations. That creates the same interpretive problem as several short-lived peptides: the reported effects, whatever their size, are described as outlasting the compound's presence in circulation by a wide margin. The usual explanation offered is that the effect is downstream — a change in gene expression or neurotrophin signalling initiated during a brief exposure and persisting afterwards — and in Semax's case that explanation has more support than most, since the strongest preclinical evidence is precisely transcriptomic. A measurable change in gene expression in rat brain after ischaemia is exactly the kind of finding that could outlast a peptide cleared in minutes. It is still an inference rather than a demonstrated human mechanism, and it is worth holding at that level of confidence. The short half-life is also part of why the intranasal route matters in the original research: direct nose-to-brain delivery is a recurring rationale in this literature, whether or not it is fully established.

Stacking — overview

Semax is most commonly discussed alongside Selank, the two being the best-known peptides from the same Russian research tradition and frequently presented as a complementary pair — Semax for attention and alertness, Selank for anxiety. Panikratova et al. studied both in the same neuroimaging work, but no clinical trial has evaluated them administered together. Each combination is covered in depth — the mechanism-level rationale, what is reported in practice, and combination-specific cautions — in the paid Semax Stacking Module included with this guide.

For how combinations are grouped by research context, the named blends, and why a pre-mixed blend vial cannot be calculated from its total milligrams, see the peptide stacks guide.

Storage & handling

• Lyophilized (unreconstituted) vials are typically stored refrigerated and protected from light; the sealed powder is generally described as stable for extended periods, and long-term storage is usually at -20 C.
• Reconstituted solution: refrigerate at ~2-8 C, protect from light, and do not freeze once mixed; commonly reported usable window is ~2-4 weeks.
• If the solution is being used intranasally rather than by syringe, the same storage constraints apply to the applicator — a nasal dropper left at room temperature is the same solution in a warmer place.

Evidence File

The Semax Evidence File: The Registry Blank, the Dev-Name Trial, and the Dose Nobody Studied

The free guide says the clinical work behind Semax is not indexed in English. That is half the story, and the smaller half. This file separates two very different absences, recovers a randomised human trial that no search for the word Semax will ever return, finds the single registry record that the same naming trick hides, reads each of the four indexed Russian trials for what it actually reports rather than what it is cited for, and traces the circulating dose, half-life and neurotrophin figures back to the papers that generated them. It closes by naming, search string by search string, what the literature does and does not contain.

• 1 registry record worldwide, under its development name only, and it enrolled rats
• 40 patients in the only randomised human trial, which a Semax search never returns
• 10x to 60x: how far every human trial dose sits above the circulating community figure
• 89.5% vs 30.8%: the only clean responder effect size anywhere in the human record

Sourcing File

Sourcing Semax: What the Sequence MEHFPGP Decides About Every Certificate

Seven residues, and four of them settle questions a generic certificate-reading guide cannot reach. This file works the Semax numbers rather than describing them: the verified identity record and the one field vendors reuse as a regulatory claim, a computed mass table covering every plausible substitute and degradation product, the arithmetic trap that lets three different correct numbers all look like the molecular weight, and salt-form maths carried all the way through to the microgram figure on a syringe. It closes with a line-by-line read of a certificate and the two questions any Semax document has to answer.

• 813.348 neutral, 813.9 average, 814.355 protonated: three correct molecular weights
• +15.995 Da, the one-methionine oxidation peak a purity percentage hides
• 300 vs 263 vs 234 mcg from the same syringe reading, on label ambiguity alone
• 0 usable absorbance at 280 nm: the sequence has no tryptophan and no tyrosine

Benefit & Outcome Review

Benefit and Outcome Review: Semax

Fourteen claims circulate for this compound across research summaries and community protocols, and they were not selected by the strength of the evidence behind them. Each is graded here on the same four questions: what was measured, in what species and system, against what comparator, and whether any human function improved rather than merely a number changing. Responder splits and time courses are given where they were published and named as missing where they were not. The verdict vocabulary is defined first, so a reader can disagree with a grade rather than with a summary of it.

• 14 circulating claims graded on the same four questions
• 2 placebo-controlled human studies exist, both imaging, neither testing performance
• 0 retrievable human reports contain a cognitive test result
• Post-course durability has never been measured for the peptide on its own

Guide FAQ

Quick answers about guide scope, access, and educational use context.