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    NA-Semax

    Nootropic PeptidePreclinical

    Also known as: N-Acetyl-Semax, N-acetyl-l-aspartyl-Semax, NAA-Semax, Semax NA, Acetyl Semax

    NA-Semax is the N-acetyl-l-aspartyl variant of Semax — the original ACTH(4-7) Pro-Gly-Pro analog developed at the Russian Academy of Sciences in the 1990s. The aspartate addition at the N-terminus is reported to improve metabolic stability against aminopeptidase cleavage, extending the in vivo half-life from minutes (parent Semax) to plausibly tens of minutes after intranasal dosing. As of 2026, NA-Semax sits in the same research-peptide tier as standard Semax — it is not FDA-approved for any indication and is sold as a research chemical with limited peer-reviewed primary literature on the acetylated variant specifically.

    Half-Life: ~20-30 minutes (intranasal, estimated from analog data)MW: ~856.0 g/mol (C39H53N9O11S)3 PubMed Studies
    Last reviewed:

    Overview

    At A Glance

    Mechanism

    Mechanism of action - pharmacological summary (research-use-only):…

    Half-Life
    ~20-30 minutes (intranasal, estimated from analog data)
    Safety Notes
    Common
    Mild nasal irritationBrief alertness spike

    Mechanism of Action

    Mechanism of action - pharmacological summary (research-use-only):

    Almost all mechanistic data come from the parent peptide Semax (Met-Glu-His-Phe-Pro-Gly-Pro); the N-acetylated analogue has no dedicated published pharmacology of its own, so the profile below is inferred from Semax, with N-terminal acetylation added for enzymatic stability.

    • BDNF / neurotrophin modulation - parent Semax is reported to raise brain-derived neurotrophic factor and related neurotrophins (NGF, NT-3) and their receptors in cortex and hippocampus, a neuroplasticity pathway characterized mainly in rodent ischemia models (Stavchansky 2011, PMID 22295573). Benefits for human cognition or mood have not been demonstrated in controlled trials.
    • Monoaminergic modulation - Semax raises striatal serotonin turnover (5-HIAA) and potentiates amphetamine-evoked dopamine release, but does not raise baseline dopamine on its own (Eremin 2005, PMID 16362768). There is no published evidence for D2-receptor sensitization or a discrete VTANAc "drive" circuit.
    • Anti-inflammatory - in rat cerebral ischemia-reperfusion, Semax blunts the ischemia-induced rise in proinflammatory transcripts including Il1a, Il1b and Il6 plus the chemokines Ccl3/Cxcl2; TNF- message was expressed too weakly to quantify in that study (Dergunova 2021, PMID 34097675).
    • Aminopeptidase resistance - N-terminal acetylation is expected to slow aminopeptidase cleavage and extend in-vivo persistence versus unmodified Semax, but no published head-to-head pharmacokinetic comparison exists, so the magnitude is unverified.

    Overview

    NA-Semax is the N-acetyl-l-aspartyl variant of Semax — the original ACTH(4-7) Pro-Gly-Pro analog developed at the Russian Academy of Sciences in the 1990s. The aspartate addition at the N-terminus is reported to improve metabolic stability against aminopeptidase cleavage, extending the in vivo half-life from minutes (parent Semax) to plausibly tens of minutes after intranasal dosing.

    As of 2026, NA-Semax sits in the same research-peptide tier as standard Semax — it is not FDA-approved for any indication and is sold as a research chemical with limited peer-reviewed primary literature on the acetylated variant specifically. Most published Semax pharmacology applies by analogy, with the caveat that the half-life difference may shift optimal dosing frequency.

    Reported nonclinical pharmacology mirrors Semax: BDNF upregulation, dopaminergic modulation in mesolimbic circuits, and increased serotonin and dopamine turnover in the cortex and hippocampus. The N-acetyl modification is reported to improve blood-brain-barrier transport, though direct PK comparisons in published literature remain thin.

    Chemical Information

    IUPAC Name

    Not yet available

    CAS Number

    Not yet available

    Molecular Formula

    C40H56N12O11

    Molecular Mass

    ~856.0 g/mol (C39H53N9O11S)

    Amino Acid Sequence

    Ac-Met-Glu-His-Phe-Pro-Gly-Pro (Ac-MEHFPGP)

    Dosing & Protocols

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    Research

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    Interactions

    Contraindications

    Research-use-only; not for human or veterinary use. No formal contraindication data exist for N-acetyl-Semax. As a precaution, this compound should not be used by:

    • Pregnant or breastfeeding individuals (no reproductive or developmental safety data).
    • Anyone with a known hypersensitivity to Semax, ACTH(4-10)-fragment peptides, or product excipients.
    • People with active psychiatric instability (e.g., mania or psychosis) or poorly controlled anxiety, given the activating/stimulatory profile of the parent peptide.
    • Anyone with significant nasal or sinus pathology if using the intranasal route.

    No human drug-interaction studies have been performed. The monoaminergic activity seen with parent Semax - potentiation of amphetamine-evoked dopamine release (Eremin 2005, PMID 16362768) - is a theoretical basis for caution when combined with stimulants or other monoaminergic/serotonergic agents.

    Research Disclaimer

    This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds.

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    Related Compounds

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    Adalank

    Nootropic PeptidePreclinical / Research compound

    Adalank is a hybrid research peptide combining structural elements of Adamax (the adamantyl-modified Semax analog) and Selank (the anxiolytic Pro-Gly-Pro tuftsin analog).

    t½ The commonly cited ~72-hour "functional duration" is an unverified community/vendor claim, not a measured value - no pharmacokinetic study of Adalank has ever been run. The figure is extrapolated from parent Adamax marketing claims. Actual serum half-life is unknown; there is no published PK data. 200-1200 mcg per dose (intranasal or subcutaneous), 1-2x daily
    PreclinicalView Profile

    Adamax

    Nootropic PeptidePreclinical / Research compound

    Adamax is a synthetic nonapeptide (Ac-MEHFPGPAG-NH2) classified as a designer analog of Semax.

    t½ No pharmacokinetic data. Community reports describe a subjectively long duration of effect (~2-3 days), supporting every-other-day or 3x/week dosing; serum half-life not characterized. 500-2000 mcg subcutaneous (community research dosing)
    PreclinicalView Profile

    Cerebrolysin

    Nootropic PeptideClinical

    Cerebrolysin is a porcine brain-derived peptide complex developed by EVER Neuro Pharma (Austria) — a low-molecular-weight neurotrophic preparation containing a mixture of free amino acids and bioactive peptides extracted from purified pig brain proteins.

    t½ ~2-4 hours (multi-component peptide mix)
    85 studiesView Profile

    Cortexin

    Nootropic PeptideMarketed in Russia/CIS (Geropharm); human clinical use with limited-quality evidence (small, mostly Russian-language studies; no Western RCT; not FDA/EMA approved)

    Cortexin is a purified peptide preparation extracted from cattle and pig cerebral cortex tissue — a low-molecular-weight neuropeptide complex used clinically in Russia and Eastern Europe for cognitive impairment, post-stroke recovery, encephalopathy, attention disorders, and pediatric developmental conditions. Like Cerebrolysin, Cortexin is positioned as a broad-spectrum neurotrophic preparation supplying bioactive peptides that mimic endogenous neurotrophic factors.

    t½ ~2-3 hours (estimated from analog peptide preparations)
    18 studiesView Profile

    NA-Semax Amidate

    Nootropic PeptidePreclinical

    NA-Semax Amidate is the C-terminally amidated NA-Semax — the carboxylic acid at the peptide's C-terminus is replaced with an amide group (-NH2), which is reported to further extend metabolic half-life by resisting carboxypeptidase cleavage in addition to the aminopeptidase resistance the N-acetyl group already provides. The practical effect is a peptide with dosing-frequency use: where standard Semax often requires 3-4 daily doses to maintain effect, NA-Semax Amidate is reported (in vendor monographs and community usage) to maintain subjective effects on a 1-2x daily schedule.

    t½ ~30-45 minutes (estimated, longer than standard Semax)
    2 studiesView Profile

    P-21

    Nootropic PeptidePreclinical

    P-21 is a synthetic cyclic dipeptide — Cyclo(L-prolyl-glycine) — derived from the Selank/Semax C-terminal Pro-Gly-Pro motif.

    t½ Not formally characterized in published work. P021 has only been studied in rodents (oral/dietary and subcutaneous dosing); no human pharmacokinetic data exist.
    4 studiesView Profile

    View Full Dosage Guide →

    Protocols, calculator & safety for NA-Semax

    Research Score

    60

    3 PubMed studies

    Quality Indicators

    Data Completeness

    75%
    Description
    Mechanism of Action
    Chemical Data
    Dosing Protocols
    Safety Profile
    PubMed Studies
    Interactions
    Vendor Listings

    Research Credibility

    3PubMed studies

    Limited research available

    Quick Facts

    Half-Life

    ~20-30 minutes (intranasal, estimated from analog data)

    Molecular Weight

    ~856.0 g/mol (C39H53N9O11S)

    Trial Phase

    Preclinical

    Safety Profile

    Low Risk

    Common Side Effects

    • • Mild nasal irritation
    • • Brief alertness spike

    Stop Use If

    • Pregnancy/lactation
    • Active mania
    • Known peptide allergy

    Research Disclaimer

    This information is for educational and research purposes only. Not intended as medical advice. Consult a healthcare professional before use.

    Frequently Asked Questions

    What is NA-Semax used for in research?

    NA-Semax is the N-acetyl-l-aspartyl variant of Semax — the original ACTH(4-7) Pro-Gly-Pro analog developed at the Russian Academy of Sciences in the 1990s. The aspartate addition at the N-terminus is reported to improve metabolic stability against aminopeptidase cleavage, extending the in vivo half-life from minutes (parent Semax) to plausibly tens of minutes after intranasal dosing.

    As of 2026, NA-Semax sits in the same research-peptide tier as standard Semax — it is not FDA-approved for any indication and is sold as a research chemical with limited peer-reviewed primary literature on the acetylated variant specifically. Most published Semax pharmacology applies by analogy, with the caveat that the half-life difference may shift optimal dosing frequency.

    Reported nonclinical pharmacology mirrors Semax: BDNF upregulation, dopaminergic modulation in mesolimbic circuits, and increased serotonin and dopamine turnover in the cortex and hippocampus. The N-acetyl modification is reported to improve blood-brain-barrier transport, though direct PK comparisons in published literature remain thin.

    What forms does NA-Semax come in?

    NA-Semax is available in vials, capsules, and sprays forms.

    How much does NA-Semax cost?

    Pricing varies by vendor and form.

    How do I compare NA-Semax vendors?

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    Research Tools

    Related Compounds

    View All

    Adalank

    Nootropic PeptidePreclinical / Research compound

    Adalank is a hybrid research peptide combining structural elements of Adamax (the adamantyl-modified Semax analog) and Selank (the anxiolytic Pro-Gly-Pro tuftsin analog).

    t½ The commonly cited ~72-hour "functional duration" is an unverified community/vendor claim, not a measured value - no pharmacokinetic study of Adalank has ever been run. The figure is extrapolated from parent Adamax marketing claims. Actual serum half-life is unknown; there is no published PK data. 200-1200 mcg per dose (intranasal or subcutaneous), 1-2x daily
    PreclinicalView Profile

    Adamax

    Nootropic PeptidePreclinical / Research compound

    Adamax is a synthetic nonapeptide (Ac-MEHFPGPAG-NH2) classified as a designer analog of Semax.

    t½ No pharmacokinetic data. Community reports describe a subjectively long duration of effect (~2-3 days), supporting every-other-day or 3x/week dosing; serum half-life not characterized. 500-2000 mcg subcutaneous (community research dosing)
    PreclinicalView Profile

    Cerebrolysin

    Nootropic PeptideClinical

    Cerebrolysin is a porcine brain-derived peptide complex developed by EVER Neuro Pharma (Austria) — a low-molecular-weight neurotrophic preparation containing a mixture of free amino acids and bioactive peptides extracted from purified pig brain proteins.

    t½ ~2-4 hours (multi-component peptide mix)
    85 studiesView Profile

    Cortexin

    Nootropic PeptideMarketed in Russia/CIS (Geropharm); human clinical use with limited-quality evidence (small, mostly Russian-language studies; no Western RCT; not FDA/EMA approved)

    Cortexin is a purified peptide preparation extracted from cattle and pig cerebral cortex tissue — a low-molecular-weight neuropeptide complex used clinically in Russia and Eastern Europe for cognitive impairment, post-stroke recovery, encephalopathy, attention disorders, and pediatric developmental conditions. Like Cerebrolysin, Cortexin is positioned as a broad-spectrum neurotrophic preparation supplying bioactive peptides that mimic endogenous neurotrophic factors.

    t½ ~2-3 hours (estimated from analog peptide preparations)
    18 studiesView Profile

    NA-Semax Amidate

    Nootropic PeptidePreclinical

    NA-Semax Amidate is the C-terminally amidated NA-Semax — the carboxylic acid at the peptide's C-terminus is replaced with an amide group (-NH2), which is reported to further extend metabolic half-life by resisting carboxypeptidase cleavage in addition to the aminopeptidase resistance the N-acetyl group already provides. The practical effect is a peptide with dosing-frequency use: where standard Semax often requires 3-4 daily doses to maintain effect, NA-Semax Amidate is reported (in vendor monographs and community usage) to maintain subjective effects on a 1-2x daily schedule.

    t½ ~30-45 minutes (estimated, longer than standard Semax)
    2 studiesView Profile

    P-21

    Nootropic PeptidePreclinical

    P-21 is a synthetic cyclic dipeptide — Cyclo(L-prolyl-glycine) — derived from the Selank/Semax C-terminal Pro-Gly-Pro motif.

    t½ Not formally characterized in published work. P021 has only been studied in rodents (oral/dietary and subcutaneous dosing); no human pharmacokinetic data exist.
    4 studiesView Profile

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