CognitiveNA-Semax-AmidateSemax N-Acetyl Amidate

N-Acetyl Semax Amidate

Longer-acting Semax variant · evidence borrowed from plain Semax · intranasal

N-Acetyl Semax Amidate is a chemically tweaked, longer-acting version of Semax — a Russian heptapeptide derived from a fragment of the stress hormone ACTH and used there as a prescription nootropic and stroke drug. Two small chemical caps (an acetyl group on one end, an amide on the other) are added to slow the enzymes that normally chew the peptide up, which is the basis for the claim that it lasts longer and can be dosed less often. The honest core of this page is that the variant has almost no research of its own: there are no dedicated human trials and no controlled preclinical studies on the acetyl-amidate specifically. Everything you read about its benefits is borrowed from plain Semax, whose own human evidence is a small set of mostly Russian-language, Russian-conducted trials that have rarely been replicated in the West (the main stroke trial had just 30 treated patients). The 'more stable' claim is chemically reasonable, but the specific numbers (such as a 30–40 minute half-life) and the 'more potent' claim are vendor extrapolation, not measured facts. Plain Semax is approved only in Russia (never by the FDA or EMA), and this variant is a research chemical approved nowhere.

The short version

Semax is a short synthetic peptide built from a fragment of ACTH (adrenocorticotropic hormone), engineered so that it keeps the brain-supporting effects of that fragment without triggering the stress/cortisol response. In Russia it is an approved prescription drug — on the country's list of essential medicines — used as a nootropic and in stroke recovery, given as nose drops or spray. It is not approved by the US FDA or the European EMA.

N-Acetyl Semax Amidate is a modified version of that same peptide. Chemists added two small protective caps — an acetyl group at one end and an amide at the other — specifically to block the enzymes that quickly break Semax down. The intent is a molecule that survives longer in the body and can therefore be taken less frequently. That chemical logic is sound; the enzymes it blocks really are the ones that destroy Semax fastest.

Here is the crucial caveat. This acetyl-amidate variant has essentially no studies of its own — no dedicated human trials, no controlled animal studies on this exact molecule. Every benefit attributed to it is actually borrowed from plain Semax. And plain Semax's own evidence is thinner than the marketing implies: it rests on a small number of mostly Russian-language trials that Western researchers have rarely repeated. The headline stroke study, for example, treated only 30 patients.

So the honest way to read this compound: a chemically reasonable 'longer-lasting Semax' whose specific claims — a 30-to-40-minute half-life, being 'more potent' — are vendor extrapolations rather than measured results, sitting on top of a parent drug that is approved only in Russia and whose evidence base has a real Western-replication gap.

Molecular identity

Specs

Molecular weight: 855.0 g/mol
Molecular formula: C₃₉H₅₄N₁₀O₁₀S
Monoisotopic mass: 854.37451 Da

Sequence: Ac-Met-Glu-His-Phe-Pro-Gly-Pro-NH₂ (acetyl + amide caps on Semax MEHFPGP) — 7 AAPubChem CID 172638603 / concordant registries
Structure / class: N-acetylated, C-amidated analog of Semax (ACTH(4-10)-derived heptapeptide); end-capped for enzymatic stabilityPubChem CID 172638603
Base peptide: Semax (Met-Glu-His-Phe-Pro-Gly-Pro), a synthetic ACTH(4-10) analogSemax literature (PubMed, concordant)
CAS / UNII: 2920938-90-3 · no UNII assigned (alternate CAS 1265823-54-2 is single-vendor, unconfirmed)Concordant chemical registries (MedChemExpress/ChemScene)
PubChem CID: 172638603PubChem (name + formula match)
Water solubility: Water-soluble; hydrophilic (parent Semax computed XLogP −2.8)PubChem CID 9811102 (parent, computed)
Molecular target: Assumed identical to Semax — BDNF/TrkB neurotrophic axis (rodent); no amidate-specific target study existsPMID 16996037 (plain Semax, rodent); borrowed, not amidate-verified
Half-life: Not measured for the amidate; N-acetylation blocks the dominant aminopeptidase cleavage (chemically plausible longer action), but the circulated '30–40 min' figure is vendor extrapolation, not trial-provenPMID 8392718 (Semax aminopeptidase degradation); Not establishedHalf-life curve →
Regulatory status: Research chemical, approved nowhere as a distinct drug (plain Semax: Russia-only)Regulatory absence (no FDA/EMA approval)

Plain English

Mechanism

All of the mechanism described here comes from plain Semax; the amidate is assumed to share it because it shares the same peptide backbone — assumed, not separately demonstrated. Semax was designed as an analog of ACTH(4-10) that keeps the neurotropic (brain-supporting) effects of that hormone fragment while dropping its corticotropic activity, meaning it is not expected to stimulate cortisol or the adrenal stress axis.

Its best-characterized mechanism is upregulation of BDNF (brain-derived neurotrophic factor) and its receptor TrkB. In rats, intranasal Semax raised hippocampal BDNF protein and increased TrkB activity, alongside improved learning — this is the main mechanistic basis for the 'nootropic' reputation, and it is animal data. Semax has also been reported to raise NGF (nerve growth factor) in animal models, and to modulate the brain's dopamine and serotonin systems (for example increasing a serotonin metabolite and amplifying amphetamine-evoked dopamine release in rodents).

An honest note on certainty: even for plain Semax, the full mechanism is not completely established — possible interactions with the melanocortin system or with enkephalin-degrading enzymes are proposed but unsettled. So the mechanistic story here is 'well-studied in rodents for plain Semax, assumed for the amidate,' not a confirmed human mechanism for this specific molecule.

Sources:PMID 16996037 PMID 16362768 PMID 11517472

Why people reach for it

Potential benefits

N-Acetyl Semax Amidate is the longer-acting take on Semax — the focus-and-drive end of the Russian nootropic tradition. Here's what draws people to it (all borrowed from plain Semax).

Sharper focus and mental drive — Its headline appeal, inherited from Semax: described as activating, raising the brain's dopamine and noradrenaline tone — the concentration and drive people pursue for demanding cognitive work.
A brain-growth (BDNF) signal — In rodent brain Semax raises BDNF and NGF and activates the TrkB receptor — the neurotrophic pairing this variant is assumed to share; that mechanism is animal data, and the amidate has none of its own.
Fewer doses for the same window — Its defining selling point: two chemical caps slow the enzymes that break Semax down, so the chemically-plausible claim is a longer-acting molecule that covers the day with fewer administrations — though the specific numbers are vendor extrapolation, not measured.
Activation without the classic stress response — Like Semax, it carries ACTH's neurotrophic signaling but is described as not driving the cortisol/stress-axis effects of the full hormone — drive without the hormonal stress load.
Pairs cleanly with a calm peptide — Because it works on drive rather than calm, it slots alongside NA-Selank-Amidate or Selank — the Russian focus-plus-calm combination in its longer-acting form.

Sources:PMID 16996037 PMID 16362768 PMID 11517472 PMID 8392718

What people reach for N-Acetyl Semax Amidate for — borrowed almost entirely from plain Semax (mechanism from animals, clinical use predominantly Russian), framed by how it's used, not proven outcomes or medical claims.

Implied timing

Best time to dose

Implied best time

Morning

Most people take N-Acetyl Semax Amidate in the morning — a more potent, longer-acting Semax, timed early to avoid late-day overstimulation.

Like Semax, it is described as activating — raising BDNF/dopamine tone — so the cognitive effect is wanted at the start of the day, when you actually want to be alert and focused.
The whole point of the amidate is a longer duration of action: an end-capped, slower-clearing molecule means a single morning dose is expected to carry further into the day, so dosing late risks overstimulation bleeding into sleep.
For the higher split (e.g. 300 mcg AM + 300 mcg early afternoon), both doses still stay in the first half of the day; evening doses are specifically avoided because the BDNF/dopamine activation can interfere with sleep onset.
No pharmacokinetic half-life has been measured for the amidate — the 'longer-acting' rationale is chemical, not a measured value — so morning timing is reasoned from the activating mechanism and how it's used, not from a published duration.

No study establishes an ideal time of day for N-Acetyl Semax Amidate — this is reasoned from its activating (Semax-borrowed) mechanism and the longer-acting chemistry, plus how it's used. As a rule of thumb most peptide dosing lands in the midday-to-evening window; for this one the lean is the early edge of that — morning.

Sources:PMID 16996037 PMID 8392718

How to run it

Dosing & protocol

N-Acetyl Semax Amidate is intranasal-primary — nasal drops or spray is the route used in Russian clinical practice and the research-chemical community. Subcutaneous injection is also used and the on-page calculator is built for it. Every dose here is borrowed from plain-Semax practice; there are no dedicated amidate trials. Read this as a map of how the compound is actually run — not a validated prescription.

Community convention borrowed from plain Semax — no dedicated amidate human trial exists, and the 'longer-acting' rationale is chemically plausible but not pharmacokinetically measured. Plain Semax is Russia-approved only; this variant is a research chemical approved nowhere. Every number here is a usage pattern, not evidence.

Tiered dose ranges

Two tiers cover the range from acute clinical reference to research-chemical nootropic use.

Low / orientation:: 100–150 mcg once daily intranasally — first-use tier; let the CNS response establish before increasing.
Standard nootropic:: 300–600 mcg/day intranasally, split into 1–2 doses; this is the community convention window most used for focus, neuroprotection, and BDNF-upregulation goals. 300 mcg once daily is the typical entry point; 600 mcg/day (split) is the higher end.
Clinical reference (plain Semax):: 12 mg/day (moderate stroke) and 18 mg/day (severe stroke) intranasally over 5–10 days — genuine Russian trial doses for plain Semax, shown for context only; they are not a research-chemical protocol and are far above the nootropic tier.
Subcutaneous tier:: 100–300 mcg subcutaneously once daily — used by those who prefer injection; the assumed longer half-life of the amidate means once-daily injection covers the window that plain Semax requires multiple doses to hold. Borrowed from Semax injection convention, not independently studied.

Administration — intranasal + subcutaneous

Intranasal is primary for this peptide: nose-to-brain delivery bypasses digestion and allows direct CNS uptake along the olfactory route.

Intranasal — delivery:: Tilt the head back slightly, deliver drops or one spray per nostril, then tilt forward so the solution contacts the upper nasal mucosa. Sniff gently — do not forcefully inhale or the solution passes into the throat and is wasted. Alternating nostrils reduces mucosal irritation over a course.
Intranasal — timing & dose split:: Morning is the standard time for once-daily dosing — see Best time to dose above; a split (e.g. 300 mcg AM + 300 mcg early afternoon) is used at the 600 mcg/day tier, both halves kept to the first half of the day. Avoid evening doses — the BDNF/dopamine activation can interfere with sleep onset.
Subcutaneous — site & rotation:: Abdomen (2+ cm from navel), outer thigh, or love-handle area. Rotate sites between doses to prevent local irritation. Drawn on a U-100 insulin syringe from the reconstituted vial — see the reconstitution card below for units.
Subcutaneous — measuring the dose:: At the standard mix (10 mg vial + 2 mL bacteriostatic water = 5,000 mcg/mL): 100 mcg = 2 IU · 150 mcg = 3 IU · 300 mcg = 6 IU. The calculator adjusts for any vial size.
Food window:: Both routes are independent of meals. Intranasal drops work best on an un-congested nasal passage; if congested, a decongestant 10–15 minutes before helps contact with the mucosa.

Cycle & washout

Semax-class peptides are used in short courses rather than continuously — this is how plain Semax was run in every Russian clinical protocol.

Standard cycle:: 10–14 days on, then a break. Research-chemical community often runs 2–4 weeks on for nootropic goals, though the original clinical pattern is the shorter 10-day block.
Washout:: Equal time off — 10–14 days rest after a 10–14 day course, or 2–4 weeks rest after a longer run. The assumed longer half-life of the amidate is not a license to skip the break; continuous receptor stimulation is not how this class was designed to be used.
On-demand option:: Some users run a single 5-day course during a high-cognitive-demand period (exam week, deadline sprint) rather than a fixed cycle. This pattern is community convention, not studied.

Reconstitution at a glance

Mixing math only — the calculator handles live unit conversion for any vial size.

Mixing:: 10 mg vial + 2 mL bacteriostatic water = 5,000 mcg per mL. On a 100-unit (1 mL) insulin syringe: 100 mcg = 2 IU · 150 mcg = 3 IU · 300 mcg = 6 IU · 500 mcg = 10 IU · 600 mcg = 12 IU.
Why 2 mL:: Matches the calculator default for this compound and keeps volumes small enough for nasal delivery (10–30 µL per drop) — standard for Semax-type heptapeptides.

Sources:PMID 11517472 PMID 16996037 PMID 8392718

Substrate the signal needs

Nutritional cofactor precision

The cofactor logic here is explicitly borrowed from plain Semax — this variant has no independent cofactor data of its own. The mechanism it shares is BDNF/NGF upregulation + dopaminergic modulation, so the three questions (supply the substrate · amplify the signal · mitigate the cost) are answered for that biology and labeled as carried over from base Semax.

Mechanistic reasoning from plain Semax's BDNF/dopamine biology — not an N-Acetyl Semax Amidate cofactor study. The amidate's own pharmacology is less verified; these are the nutrients that feed the biology it is assumed to share.

Supply the substrate — acetylcholine + dopamine precursors

Semax modulates both cholinergic (memory/attention) and dopaminergic (drive/focus) tone. Keeping the raw materials stocked amplifies whatever signal the peptide is driving.

Alpha-GPC or CDP-Choline:: 300–600 mg Alpha-GPC (or 250–500 mg CDP-Choline) with breakfast. Choline is the direct precursor to acetylcholine — the memory-and-attention neurotransmitter. Borrowed from Semax: any stimulus that sharpens the cholinergic system draws down choline faster; supplying it prevents the headache/brain-fog that marks choline deficit.
L-Tyrosine:: 500–1,000 mg on an empty stomach, 30–60 minutes before dosing. Tyrosine is the amino-acid backbone the body builds dopamine and norepinephrine from. Semax increases dopamine turnover in mice; keeping the precursor pool full lets that signal go further.
Omega-3 DHA:: 1–2 g DHA daily with a fat-containing meal. DHA is the structural fat that makes up neuronal cell membranes — the physical surface on which BDNF receptor signaling occurs. Borrowed from Semax's BDNF mechanism.
B6 · B9 · B12:: A methylated B-complex daily (methylcobalamin B12, methylfolate B9, P-5-P B6). These are the enzymatic cofactors the body uses to synthesize dopamine and serotonin from their precursors, and to run the methylation cycle that keeps homocysteine in check. Baseline substrate for any neurotransmitter-active peptide.

Amplify the BDNF / neuroplasticity signal

Semax's headline mechanism is BDNF upregulation. Two inputs amplify the same signal — neither requires a supplement.

Aerobic exercise:: 20–30 minutes of moderate aerobic exercise on dosing days, ideally within 2 hours of the intranasal dose. Exercise is one of the best-established BDNF inputs independently; pairing it with a BDNF-upregulating peptide is additive signal, not redundancy. Borrowed from Semax's BDNF mechanism.
Sleep (7–9 hours):: BDNF consolidation and synaptic pruning — the plastic benefit Semax is meant to open the window for — occur during deep sleep. Running this peptide on 5-hour nights wastes the signal. Optimize sleep before adding anything else.
Magnesium L-threonate:: 144 mg elemental Mg (as MgL-threonate, e.g. Magtein) at bedtime. This form crosses the blood-brain barrier and raises brain magnesium levels, supporting NMDA receptor tone and the synaptic plasticity BDNF drives. Pairs with the sleep amplifier above.

Mitigate — minimal cost, one watch item

The amidate's side-effect burden is low (same as plain Semax: generally well-tolerated). One item is worth managing.

Overstimulation / sleep disruption:: The dopaminergic and activating character of Semax can push sleep onset later if dosed in the afternoon or evening. Strict morning dosing (or morning + early-afternoon for the split) is the mitigation — no additional supplement required. If persistent: consider dropping to a single 300 mcg morning dose.

Combinations + timing

Stacking notes + timing windows

N-Acetyl Semax Amidate occupies the focus/drive/neuroprotection side of the Russian nootropic pairing. The complementary partner takes the calm side. A second 'stack' is comparison with the parent — base Semax is not a true stack partner but a swap/comparison worth understanding.

User combinations reasoned from complementary mechanisms — none studied head-to-head, and the amidate itself has no human trial, so every stack here is doubly unproven. Doses are community convention. 'Reached for' describes where users go, not a proven indication.

NA-Semax-Amidate + NA-Selank-Amidate

The primary stack: focus and drive (this peptide) paired with calm and anxiolysis (N-Acetyl Selank Amidate). The Russian nootropic pairing, both in their longer-acting amidate form.

Why it works:: N-Acetyl Selank Amidate is the anxiolytic, GABAergic complement to Semax's stimulating/noradrenergic character. Semax without the Selank pair can produce edge or restlessness in sensitive users; Selank without Semax can be too sedating for productivity. Together they are the classic Russian 'productive calm' combination — two different levers, not the same one twice.
The protocol:: NA-Semax-Amidate 300 mcg intranasally AM + NA-Selank-Amidate 300 mcg intranasally AM (same session). Both can be delivered sequentially in the same nostril-swap routine. Subcutaneous option: 100–150 mcg each, injected together once daily. Start each at the lower end before combining.
Outcome:: Reached for on sustained cognitive output without anxiety, creative focus, or high-stress periods where the activating side alone would be dysphoric. Inherits the same Russian-evidence-limited caveat as each peptide individually.

NA-Semax-Amidate + Selank

Same pairing logic as above, using the shorter-acting Selank base form instead of the amidate — simpler to source, more dosing flexibility.

Why it works:: Selank (the original Russian heptapeptide) has a slightly larger published evidence base than NA-Selank-Amidate, though still predominantly Russian. The complementary mechanism is identical — anxiolytic/GABAergic calm against Semax's stimulating BDNF/dopamine push. Some users prefer the base Selank's shorter window for afternoon dosing (less overnight anxiolytic bleed).
The protocol:: NA-Semax-Amidate 300 mcg intranasally AM + Selank 300–600 mcg intranasally AM. Selank may be repeated mid-day if the afternoon has a second demanding window. Subcutaneous option mirrors the above.
Outcome:: Same 'productive calm' goal as the amidate pairing; chosen when the shorter Selank window is an advantage or when NA-Selank-Amidate is harder to source.

Base Semax — parent comparison, not a stack

Semax (plain Semax) is the evidence backbone this entire page is built on. Running both simultaneously is redundant — they share the same mechanism.

Why not a true stack:: NA-Semax-Amidate IS a modified Semax — combining the two is pushing the same BDNF/dopamine lever twice. This is the exact redundancy to avoid. The choice is a SWAP: use whichever form you prefer, not both.
When to prefer plain Semax:: Semax has more published evidence (still thin, still Russian-limited, but more than the amidate). If evidence fidelity matters more than dosing convenience, the base form is the honest choice. It requires more frequent dosing (shorter half-life) and may be easier to source in some markets.
When to prefer the amidate:: If the assumed longer-acting profile is the goal — fewer daily doses, a more stable trough — and you accept that the 'more stable / more potent' claims are vendor extrapolation rather than measured fact, the amidate is the community choice. The honest read: you're betting on a plausible chemical rationale.

Reconstitution math

Reconstitution calculator

Calculated for a 1 mL U-100 insulin syringe (100 units/mL).

Peptide per vial

BAC water added

Desired dose

Units per dose

Draw to this mark on a U-100 syringe

Volume per dose: 0.06 mL
Doses per vial: 33
Concentration: 5 mg/mL

One vial lasts

Daily: 33 days
Every other day: 66 days
5×/week: 46 days

Research use only. Not for human consumption. Outputs are reference values based on research literature — verify all measurements independently.

From the studies

Side effects from research

Plain Semax is generally reported as well-tolerated in Russian clinical use, including intranasal stroke dosing, with a favorable reported side-effect profile. The important caveat is that this rests on the same small, mostly-Russian, often-unblinded evidence base — it is not the same as Western pharmacovigilance or large randomized-trial safety data.

There is no dedicated safety study of the N-acetyl-amidate variant. Its safety is assumed from plain Semax, including the assumption that it will not stimulate the cortisol/stress axis (a property of plain Semax's design that has not been re-confirmed for the amidate). Long-term and high-dose safety is unknown and unstudied, which matters especially for the supraphysiologic 'nootropic' research-chemical dosing tier.

Honest summary: a reassuring tolerability reputation, but one that belongs to plain Semax and to a limited evidence base — not to controlled safety testing of this specific modified molecule.

Sources:PMID 11517472

As reported in literature

Research dosing ranges

These are the doses that exist in the literature — and they are almost all plain Semax, mostly from Russian trials, applied to the amidate by extrapolation. There is no dedicated human (or controlled animal) dosing study of the acetyl-amidate variant. The rows separate what was actually measured (plain Semax) from what is assumed or vendor-sourced (the amidate). All clinical dosing was intranasal.

Dose	Route	Model	Outcome	Sources:
12 mg/day (moderate); 18 mg/day (severe)	Intranasal	Human RCT — acute hemispheric ischemic stroke, plain Semax (n=30 treated vs 80 control)	Faster regression of cerebral and focal (especially motor) deficits vs conventional therapy — Russian-language trial, small, not Western-replicated	PMID 11517472
50 µg/kg intranasal	Intranasal (rat)	Rats — hippocampal BDNF/TrkB, plain Semax	↑ BDNF protein and TrkB activity, improved conditioned-avoidance learning — ANIMAL mechanistic data	PMID 16996037
Single/repeated dosing	Systemic (mouse)	Mice — striatal monoamines, plain Semax	↑ serotonin metabolite (~+25%), amplified amphetamine-evoked dopamine and locomotion — ANIMAL neurochemistry	PMID 16362768
~300–1,000 µg/day (vendor)	Intranasal	N-Acetyl Semax Amidate — 'nootropic' research-chemical practice	Vendor/community dose tier with NO trial validation; the 'longer-acting, dose-less-often' rationale is extrapolated, not measured	PMID 8392718

Quick answers

Frequently asked

How is this different from regular Semax?

It is plain Semax with two chemical caps added — an acetyl group at one end and an amide at the other — to slow the enzymes that break it down. The intended result is a longer-acting molecule that can be dosed less often. The peptide backbone, and the claimed effects, are otherwise the same as Semax.

Are there studies on the amidate specifically?

Essentially none. There are no dedicated human trials and no controlled preclinical studies on the acetyl-amidate variant itself. Everything attributed to it is borrowed from plain Semax research.

Is the 'longer half-life' claim true?

The direction is chemically reasonable — acetylation blocks the main enzyme that degrades Semax, so a slower breakdown is plausible. But the specific number often quoted (a 30–40 minute half-life) is not traceable to any primary pharmacokinetic study; it is vendor-sourced and should be treated as unverified.

Is Semax FDA-approved?

No. Plain Semax is a prescription drug in Russia (on its list of essential medicines) but is not approved by the US FDA or the European EMA. The N-acetyl amidate variant is a research chemical approved nowhere as a distinct drug.

How is it taken?

Intranasally, as nose drops or spray, in cyclical on/off courses rather than continuously. There is no oral form. Reconstitution and administration technique are outside the scope of this page.

Is it banned in sport?

It is not named on the 2026 WADA Prohibited List, but because Semax-class peptides upregulate growth factors like BDNF and NGF, it could plausibly fall under the S2 growth-factor category, and as a non-approved substance it could fall under S0. Treat it as prohibited-by-inference and confirm with an anti-doping authority before any competitive use.

Primary sources

References

PMID 11517472Effectiveness of Semax in acute hemispheric ischemic stroke — Zh Nevrol Psikhiatr Im S.S. Korsakova 1997 (Russian; n=30 treated vs 80 control; 12/18 mg/day) — PLAIN SEMAX
PMID 16996037Dolotov et al., Brain Research 2006 — Semax regulates BDNF and TrkB expression in the rat hippocampus (animal; plain Semax)
PMID 16362768Eremin et al., Neurochem Res 2005 — Semax activates dopaminergic and serotoninergic brain systems in rodents (animal; plain Semax)
PMID 8392718Potaman et al., Peptides 1993 — degradation of ACTH(4-10)/Semax by rat serum enzymes (aminopeptidase-dominant; mechanistic basis for N-acetyl stabilization)
PubChem CID 172638603PubChem Compound — N-acetyl semax amidate, CID 172638603 (C39H54N10O10S; authoritative for identity)
WADA 2026WADA 2026 Prohibited List — S2 (peptide hormones / growth factors) and S0 (non-approved substances); Semax-class not named (status by inference)

Research use only · Not medical advice · Updated 2026-06-01