Educational use only — not medical advice. This guide summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.
NA-Semax Amidate at a glance
- What it is
- Semax (Met-Glu-His-Phe-Pro-Gly-Pro, a synthetic ACTH(4-7) analog extended with Pro-Gly-Pro) carrying an acetyl group on the N-terminus and an amide on the C-terminus. The core seven residues are unchanged; only the two ends are capped.
- Researched for
- Cognition, memory, attention and neuroprotection — all of it in the parent Semax literature. A PubMed search for the acetylated/amidated analog returns no studies of its own.
- Commonly reported range
- Roughly 300–900 mcg per day in vendor and community protocols, often split across one to three administrations. Examples of what is reported, not a recommendation, and not derived from a study of this analog.
- Route reported
- Intranasal is the most commonly described route; subcutaneous injection is also reported.
- Reported frequency
- Once to three times daily in reported protocols.
- Reported cycle
- Roughly 30–60 days followed by a washout, as commonly described in community sources.
- Plasma half-life
- Not established for the analog, and poorly established for Semax itself. The one indexed measurement — Semax incubated with rat brain plasma membranes — reports a half-life longer than one hour, which is an in-vitro membrane figure rather than a blood half-life. The "few minutes" and "about 30 minutes" numbers commonly quoted are not traceable to a study.
- Regulatory status
- Not FDA-approved; research use only in the US. Parent Semax is a registered medication in Russia and has no US registry presence — a ClinicalTrials.gov search for Semax returns zero studies.
Reported ranges from research/community — examples, not recommendations.
What it is / mechanism
The useful thing to understand about this compound is what its two modifications are for, and that can be answered precisely rather than with the usual "more stable" phrasing. Semax is Met-Glu-His-Phe-Pro-Gly-Pro, and the published work on how it is broken down identifies the routes specifically. A 2006 study in Amino Acids (PMID 16773243) tracked degradation of uniformly tritium-labelled Semax in the presence of plasma membranes and of glial and neuronal cell cultures from rat basal forebrain, and reported that the splitting away of ME — the N-terminal dipeptide — and of GP — the C-terminal dipeptide — together with formation of pentapeptides, are the predominant processes. An earlier study of Semax at rat forebrain basal-nuclei membranes (PMID 15344653) attributes the breakdown mainly to dipeptidyl aminopeptidases, which cleave Semax successively to the pentapeptide HFPGP and then to the tripeptide PGP. So degradation proceeds by chewing dipeptides off both ends. That is exactly what the two modifications address: acetylating the N-terminus removes the free amino group an aminopeptidase requires, and amidating the C-terminus removes the free carboxyl group a carboxypeptidase requires. The design is coherent and the target of each cap is identifiable in the literature. What follows that, and matters just as much, is that nobody has published a measurement of whether it works. The analog has no indexed studies, so its stability advantage is an inference from Semax's degradation chemistry rather than an observed result — a well-reasoned prediction, not a finding. As for what Semax does once it is present, the parent literature describes blood-brain-barrier penetration and upregulation of BDNF and NGF with associated TrkB signalling, plus modulation of dopaminergic, serotonergic and enkephalin systems. The same 2004 membrane study measured specific, reversible, calcium-dependent binding at rat forebrain basal-nuclei membranes with a dissociation constant of 2.41 ± 1.02 × 10⁻⁹ M and a binding-site density of 33.5 ± 7.9 × 10⁻¹⁵ mol per mg of protein — nanomolar affinity, which is a real and rarely quoted number for this family.
Researched effects
In the parent Semax research and in community reports, the Semax family is associated with improved focus, working memory and mental clarity, a mild alerting effect, and reported neuroprotective and stress-buffering properties; Semax studies describe BDNF elevation and increased TrkB expression, with neurotrophic upregulation building over hours rather than minutes. Two qualifications belong with all of that. The first is that N-Acetyl Semax Amidate has never been the subject of a study, so every effect attributed to it is inherited from a different molecule that happens to share its core sequence. The second is that the bulk of the Semax clinical literature is Russian and was produced in the regulatory environment where Semax is a registered medicine; it is not indexed in the US trial registry, and a search of ClinicalTrials.gov for Semax returns nothing at all. Neither point makes the parent findings wrong. Both mean the evidence is thinner and less independently checked than the confidence of most vendor copy suggests.
Evidence & regulatory status
- Evidence for the analog itself: none indexed. A PubMed search for N-acetyl semax returns zero records, and searches for the amidated form return nothing describing this compound. Its properties are extrapolated from the parent Semax literature plus the chemistry of terminal capping.
- Evidence for the parent: Semax has a real published record, concentrated in Russian journals and covering cognition, stroke recovery and neuroprotection, plus mechanistic work on receptor binding and degradation that is indexed in PubMed and cited on this page. Note that the field itself studies terminal modification of this peptide — a 2013 paper (PMID 23821053) specifically examined proteolysis of Semax analogues with different N-terminal amino acids by carboxypeptidases — so the modification concept is not a vendor invention, even though this particular modified product is unstudied.
- Registry: zero studies for Semax on ClinicalTrials.gov, and none for the analog. Semax's approval is a Russian national registration, not an FDA one, and the acetylated/amidated form is not separately registered anywhere.
- Regulatory: not FDA-approved and sold in the US for research use only. Not explicitly named on the WADA Prohibited List, though non-approved substances can fall under the catch-all category S0 — athletes should verify current rules directly rather than rely on a guide page.
- Research-use: provided strictly as a research chemical for laboratory and educational purposes. Content here describes what is reported in studies and community discussion and is not a recommendation for human use.
Dosage — reported ranges (overview)
The figures below are examples of what vendor and community protocols report, not a recommendation and not a personal dose. Intranasal use is the most commonly reported route, with daily totals around 300–900 mcg — roughly 600 mcg/day is the most frequently cited midpoint — often split into one to three administrations. Subcutaneous protocols are reported in a similar range, roughly 250–1,000 mcg/day. Reported cycles run about 30–60 days followed by a washout, with lower daily amounts on longer cycles. Some sources suggest using slightly less than a typical Semax protocol on the reasoning that the modified analog resists degradation better. That reasoning is plausible and completely untested: no study has compared the two, so there is no measured potency ratio between Semax and its capped form, and adjusting a number on the strength of an untested inference is worth recognising as a guess rather than a calculation.
A printable protocol sheet with a reconstitution reference and an injection log comes with All-Access Lifetime.
Reconstitution — bac-water math
Reconstitution here is concentration math only — it defines how much peptide sits in each unit of liquid, not a personal dose. NA-Semax Amidate is measured in micrograms, so on a U-100 insulin syringe (100 units = 1 mL) the concentration in mcg/mL is total peptide mcg divided by water volume in mL, and the units to draw for a target amount D in mcg are D ÷ (mcg/mL) × 100. Worked example: a 10 mg vial is 10,000 mcg, so reconstituted with 2 mL of bacteriostatic water it gives 5,000 mcg/mL; a 300 mcg example is 300 ÷ 5,000 × 100 = 6 units, and a 900 mcg example is 18 units. Add water slowly down the vial wall to avoid foaming, and do not shake. Every row below sits between 3 and 27 units, well within the 100-unit capacity of a single U-100 syringe — note how small these draws are, which is why a 30- or 50-unit syringe reads more accurately here than a 100-unit barrel.
| Bac water added | Concentration | 300 mcg (low example) | 900 mcg (high example) |
|---|
| 1 mL | 10,000 mcg/mL (10 mg/mL) | 3 units (0.03 mL) | 9 units (0.09 mL) |
| 2 mL | 5,000 mcg/mL (5 mg/mL) | 6 units (0.06 mL) | 18 units (0.18 mL) |
| 3 mL | 3,333 mcg/mL (~3.33 mg/mL) | 9 units (0.09 mL) | 27 units (0.27 mL) |
This is concentration math, not a dose recommendation.
Injection / administration basics
For subcutaneous research handling, reported practice uses a small insulin syringe — 30- or 50-unit — for accuracy at these low microgram volumes, drawing into subcutaneous tissue of the abdomen, thigh or upper arm at roughly a 45-degree angle, rotating sites. For the intranasal route, formulations are dispensed as a metered spray, commonly 0.1% or 0.3%, delivering about 300 mcg per pump, with a pause of about a minute between applications to each nostril. All of this describes reported handling, not medical instruction. One practical note that follows from the concentration table: at 10,000 mcg/mL a 300 mcg amount is three units, and three units is close to the resolution limit of a 100-unit syringe — using more water to make a weaker solution buys measurement accuracy, which is the opposite of the instinct to keep injection volume small.
Half-life & frequency rationale
No half-life has been published for N-Acetyl Semax Amidate, and the figures commonly quoted for it and for its parent do not hold up well when traced. An earlier version of this page said standard Semax clears within minutes and that the acetyl/amide modification extends that to roughly 30 minutes. Neither number could be traced to a study, and the one indexed measurement points the other way: the 2004 study of Semax at rat forebrain basal-nuclei plasma membranes (PMID 15344653) reports the peptide's half-life in the presence of those membranes as longer than one hour. That figure needs its context stated rather than swapped in as a replacement — it is an in-vitro measurement against a membrane preparation, not a plasma half-life in a living animal, and the two are not interchangeable. The honest summary is that Semax's in vivo circulating half-life is not something the indexed literature settles, and for the capped analog there is no measurement at all. What can be said with confidence is directional: capping both termini blocks the specific exopeptidase cleavages that the degradation studies identify as dominant, so a longer functional life than Semax is the reasonable expectation. Expectation is the correct word. Separately, and independent of clearance, the downstream neurotrophic changes reported in Semax studies build over hours and outlast the peptide's presence, so circulating half-life is not a good proxy for duration of effect in this family.
Side effects, safety & contraindications
Human safety data for NA-Semax Amidate specifically does not exist, and most of what is said about its tolerability is inherited from the parent Semax. Reported and anticipated effects include overstimulation or anxiety at higher amounts, irritability or disrupted sleep, and — with intranasal use — nasal or throat irritation. Subcutaneous use may produce local injection-site reactions such as redness, swelling or discomfort. Some sources caution against combining it with other nootropics given how thin the safety data is. It is worth adding one point that the stability rationale implies: if the modifications do what they are designed to do, the analog persists longer than Semax, which means any effect — wanted or unwanted — plausibly persists longer too. That cuts both ways and is not accounted for in protocols copied across from Semax. None of this substitutes for professional medical evaluation.
Stacking — overview
The most established pairing in community and vendor discussion is Semax with Selank, or their modified analogs together: Semax is described as providing dopaminergic and BDNF-mediated cognitive stimulation while Selank contributes anxiolytic, GABAergic stabilisation, the idea being that Selank smooths the stimulating edge. These are examples of how the combination is described, not recommendations, and no controlled study of the pairing exists in either the parent or the modified forms. From this library, the peptides most often mentioned alongside NA-Semax Amidate are listed below.
Semax + Selank ("nootropic pair")
NA-Semax Amidate for focus and BDNF with Selank or NA-Selank Amidate for anxiolytic balance — the most commonly discussed combination, and one with no controlled study behind it in any form.
Cognition + neuroprotection
NA-Semax Amidate with Epithalon, reported in longevity- and neuroprotection-oriented discussion.
Recovery-oriented pairing
NA-Semax Amidate alongside BPC-157, reported by users pursuing general recovery and neurological support.
Sleep counterbalance
NA-Semax Amidate in the daytime with DSIP, reported as a way to offset stimulant-like effects that can disrupt sleep.
Stacking across compounds
The overview above covers NA-Semax Amidate. The cross-compound material — which pairings are redundant rather than additive, where interaction risk is documented versus merely unstudied, and the blend arithmetic worked end to end — lives in the Peptide Stacking Guide, which is free to read in outline and $39 in full (included with All-Access Lifetime).
Included with this guide
The NA-Semax Amidate Stacking Module
The overview above is the free summary. The NA-Semax Amidate Stacking Module goes through each combination in depth — the mechanism-level reason it is proposed, what is actually reported in practice, and the cautions specific to that pairing — plus what to avoid and why. Included with NA-Semax Amidate Standard Access.
- How to think about stacking NA-Semax Amidate — 4 principles
- 3 combinations covered in detail
- What to avoid, and why — 4 items
- Combination-specific cautions
Combinations covered: Calm-focus pairing, Cognition + neuroprotection, Sleep counterbalance.
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 (freeze-dried) powder is reported to be stable refrigerated at 2–8 °C and can be kept frozen for longer-term storage; keep it away from light and moisture until reconstituted.
- Once reconstituted with bacteriostatic water, refrigerate at 2–8 °C and use within a few weeks; avoid freezing the reconstituted solution and do not shake. Bacteriostatic water's benzyl alcohol preservative is what allows repeated withdrawals from one vial — sterile water has no preservative and is intended for single use.
References
Primary sources for this guide: PMID 16773243 (Amino Acids, 2006) for the degradation pathway showing N-terminal ME and C-terminal GP removal as the predominant processes; PMID 15344653 (Bioorganicheskaia Khimiia, 2004) for Semax receptor binding at rat forebrain basal-nuclei membranes (Kd 2.41 ± 1.02 × 10⁻⁹ M, Bmax 33.5 ± 7.9 × 10⁻¹⁵ mol/mg protein), the dipeptidyl-aminopeptidase degradation route to HFPGP and PGP, and the greater-than-one-hour membrane half-life; PMID 23821053 (Doklady Biological Sciences, 2013) for proteolysis of Semax analogues with modified N-termini by carboxypeptidases; and PMID 16637290 (2006) for the tritium-labelling method used across this degradation work. Registry status checked against ClinicalTrials.gov. Where an earlier version of this page carried half-life figures of a few minutes for Semax and about 30 minutes for the analog, those have been withdrawn rather than corrected silently, because neither could be traced to a source.
Related peptide guides
Continue exploring related educational guide topics in the Medibact library.
Guide FAQ
Quick answers about guide scope, access, and educational use context.
How is N-Acetyl Semax Amidate different from regular Semax?
It is the same seven-residue Semax sequence with both ends capped — an acetyl group on the N-terminus and an amide on the C-terminus. The core peptide is unchanged. The purpose of the caps is to block enzymatic breakdown, and the published degradation work makes it possible to say exactly which breakdown: studies of Semax report that the predominant routes are removal of the N-terminal ME dipeptide and the C-terminal GP dipeptide by exopeptidases, and each cap removes the free terminus one of those enzyme classes needs. The design is sound in principle. Whether it delivers has not been measured, because the modified analog has no published studies of its own.
Which enzymes and which bonds do the modifications actually block?
Exopeptidases that work inward from the ends. A 2006 study in Amino Acids (PMID 16773243) tracking labelled Semax in the presence of brain plasma membranes and glial and neuronal cultures found that splitting off ME from the N-terminus and GP from the C-terminus were the predominant degradation processes. A 2004 study (PMID 15344653) attributes the breakdown mainly to dipeptidyl aminopeptidases, cleaving Semax to the pentapeptide HFPGP and then to the tripeptide PGP. N-terminal acetylation eliminates the free amino group an aminopeptidase binds; C-terminal amidation eliminates the free carboxyl group a carboxypeptidase binds. That the field studies this deliberately is confirmed by a 2013 paper on the proteolysis of Semax analogues with different N-terminal residues by carboxypeptidases (PMID 23821053).
What is the half-life of N-Acetyl Semax Amidate?
It has not been measured. Neither, in a form worth quoting, has the parent's. The one indexed figure is from Semax incubated with rat forebrain plasma membranes, where the half-life was reported as longer than one hour — an in-vitro membrane measurement, not a blood half-life, and not transferable to either. The commonly circulated "a few minutes for Semax, about 30 minutes for the amidate" pairing appeared on an earlier version of this page and has been withdrawn because neither number traces to a study. Note also that in this family the neurotrophic effects reported downstream build over hours and outlast the peptide itself, so half-life would be a poor guide to duration of effect even if it were known.
Has N-Acetyl Semax Amidate been studied in humans?
No, and not in animals either — it has no indexed studies at all. Everything attributed to it comes from the parent Semax. Semax itself has a genuine published record, largely Russian, where it is a registered medication; it is not in the US trial registry, and a ClinicalTrials.gov search for Semax returns zero studies. So the evidence chain runs: a real but geographically concentrated literature on one molecule, plus a chemically reasonable prediction about a modified version of it that nobody has tested.
What is the molecular weight of N-Acetyl Semax Amidate, and why does it differ from Semax?
The two caps change the mass in a defined way. Acetylation of the N-terminus adds an acetyl group in place of a hydrogen, a net addition of about 42 daltons. C-terminal amidation replaces the terminal hydroxyl with an amide, a net change of about −1 dalton. So the capped analog runs roughly 41 daltons heavier than the parent heptapeptide. This is worth knowing when reading a certificate of analysis: a mass-spectrometry result should match the capped mass, not Semax's, and a report showing the parent's mass on a product sold as the amidate is a discrepancy rather than a rounding difference.
Is it taken as a nasal spray or an injection?
Both routes are reported, and intranasal is the more commonly described one — metered sprays around 0.1% or 0.3% delivering roughly 300 mcg per pump. Subcutaneous injection is also used. This guide describes reported practice; it is not a recommendation to use it by either route.
How do I reconstitute it, and what does a 300 mcg draw look like?
Concentration is total micrograms divided by millilitres of bacteriostatic water. A 10 mg vial is 10,000 mcg; with 2 mL of water that gives 5,000 mcg/mL, so a 300 mcg example is 0.06 mL, or 6 units on a U-100 insulin syringe, and a 900 mcg example is 18 units. Using more water gives a weaker solution and a larger, easier-to-read draw — at these microgram amounts, measurement accuracy is the constraint, and a 30- or 50-unit syringe reads a small volume better than a 100-unit barrel. This is arithmetic, not a dose.
What dose is commonly reported?
Reported protocols cluster around 300–900 mcg per day, often cited near 600 mcg/day, split into one to three administrations, on cycles of roughly 30–60 days with a washout. Those are examples of what is reported, not a personal dose. They also carry over from Semax protocols, and because no study has compared the capped analog to the parent, there is no measured basis for adjusting between them.
Is N-Acetyl Semax Amidate legal or approved?
It is not FDA-approved and is sold in the US for research use only. The parent Semax is a registered medication in Russia, but the acetylated and amidated analog is not separately registered there or anywhere else. It is not explicitly named on the WADA Prohibited List, though non-approved substances can fall under category S0 — athletes should check current rules directly rather than rely on this page.
Is there a certificate of analysis worth checking for this compound?
Yes, and the mass is the field to read first. Because the identity of this product is defined entirely by its two terminal caps, a mass-spectrometry result is what distinguishes it from plain Semax — the capped form should run roughly 41 daltons heavier. Purity by HPLC tells you how much of the sample is the main peak; it does not tell you that the main peak is the capped molecule rather than the uncapped one. Our explainer on reading a peptide certificate of analysis covers which fields on a report are checkable and which are not.
Compliance and trust notes
- Educational content only; no personalized health or outcome claims.
- No personalized use recommendation outputs.
- Use this material for general learning and research-context literacy.
