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preclinicalCognitive & Anxiety

N-Acetyl Semax Amidate

Also known as: NASA, Ac-Semax-NH₂, N-Acetyl Semax Amide

N-Acetyl Semax Amidate (NASA) is a modified derivative of Semax, itself an analog of ACTH(4-10). The N-terminal acetylation and C-terminal amidation provide enhanced metabolic stability and potentially improved blood-brain barrier penetration compared to native Semax. It retains Semax's nootropic and neuroprotective properties — BDNF upregulation, serotonergic modulation, and cognitive enhancement — while potentially offering longer duration of action and greater potency. It is widely used in the nootropic research community.

4 cited references·5 researched benefits

Quick Answer

N-Acetyl Semax Amidate (NASA) is an enhanced derivative of the Russian nootropic Semax, with N-terminal acetylation and C-terminal amidation for improved metabolic stability. It retains Semax's cognitive-enhancing properties — BDNF upregulation, serotonin/dopamine modulation, and neuroprotection — with potentially longer duration and better bioavailability. Not approved by any regulatory agency, it is used in the research nootropics community for cognitive enhancement and mood support.

Key Facts

Mechanism
N-Acetyl Semax Amidate retains the core ACTH(4-10) heptapeptide sequence (Met-Glu-His-Phe-Pro-Gly-Pro) with terminal modifications that resist aminopeptidase and carboxypeptidase degradation. The mechanism parallels Semax: it does not activate melanocortin receptors at nootropic doses but instead modulates neurotrophic factor expression (upregulating BDNF and NGF), enhances monoaminergic neurotransmission (serotonin, dopamine, norepinephrine), and influences gene expression in neurons. The acetyl and amide modifications may improve lipophilicity and passive diffusion across the blood-brain barrier compared to the unmodified peptide.
Research Status
preclinical
Half-Life
~60–90 minutes (estimated; longer than Semax due to terminal modifications)
Primary Use
Cognitive & Anxiety
Table of Contents

Benefits

  • Enhanced stability — terminal modifications provide resistance to enzymatic degradation, potentially extending duration of effectmoderate
  • BDNF upregulation — increases brain-derived neurotrophic factor expression, supporting neuroplasticity and cognitive functionmoderate
  • Cognitive enhancement — improves attention, memory consolidation, and learning in preclinical modelsmoderate
  • Neuroprotection — may protect neurons from oxidative stress and excitotoxicity through neurotrophic factor upregulationpreliminary
  • Mood support — modulation of serotonergic and dopaminergic systems may improve mood and reduce anxietypreliminary

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intranasal spray100–600 mcg1–2× dailyMost commonly administered intranasally for direct CNS access via the olfactory pathway. Not approved for therapeutic use. Research and nootropic community dosing based on Semax protocols with adjustment for enhanced potency.
Subcutaneous injection100–300 mcg1× dailySome researchers use subcutaneous injection for more consistent bioavailability. Higher systemic exposure but BBB penetration may be less efficient than intranasal route.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Nasal irritation — mild discomfort with intranasal administration, the most common routecommon
  • Headache — occasionally reported, typically mild and transientrare
  • Fatigue — some users report tiredness, potentially from serotonergic modulationrare
  • Overstimulation — rare reports of anxiety or jitteriness at higher dosesrare

Frequently Asked Questions

What is the difference between Semax and N-Acetyl Semax Amidate?
Semax is the base heptapeptide analog of ACTH(4-10) with a Pro-Gly-Pro C-terminal extension. N-Acetyl Semax Amidate adds two modifications: acetylation of the N-terminal amino group and amidation of the C-terminal carboxyl group. These modifications protect against exopeptidase degradation, potentially increasing the peptide's half-life by 2–3×. Some users report that NASA has a smoother onset and longer-lasting effects than standard Semax, though comparative clinical data is lacking.
Is N-Acetyl Semax Amidate FDA-approved?
No. Neither Semax nor any of its derivatives are FDA-approved in the United States. Semax is approved in Russia as a nootropic and neuroprotective medication. N-Acetyl Semax Amidate is available as a research compound and is used in the nootropic community. It has not undergone formal clinical trials in Western regulatory frameworks. Users should understand that quality, purity, and safety have not been evaluated by regulatory authorities.
How does NASA compare to N-Acetyl Selank Amidate?
Both are enhanced derivatives of Russian nootropic peptides with the same terminal modifications. NASA (from Semax, an ACTH analog) is primarily nootropic and neurostimulatory — it enhances focus, attention, and cognitive performance. N-Acetyl Selank Amidate (from Selank, a tuftsin analog) is primarily anxiolytic and immunomodulatory — it reduces anxiety without sedation and modulates immune function. They are often used together as a complementary "stack" by nootropic researchers.
What is BDNF and why does its upregulation matter?
Brain-Derived Neurotrophic Factor (BDNF) is a protein that supports neuronal survival, promotes synaptic plasticity (the basis of learning and memory), and drives neurogenesis in the hippocampus. Low BDNF levels are associated with depression, cognitive decline, and neurodegenerative diseases. Interventions that increase BDNF — exercise, antidepressants, and potentially peptides like Semax/NASA — may improve cognitive function and mood. However, the specific magnitude of BDNF increase from NASA and its clinical significance in humans requires further study.

References

  1. 1
    Semax and its derivatives: molecular mechanisms of nootropic and neuroprotective action(2007)PubMed ↗
  2. 2
    Effects of Semax on BDNF and NGF expression in rat brain(2008)PubMed ↗
  3. 3
    ACTH(4-10) analogs: structure-activity relationships and neuroprotective properties(2005)PubMed ↗
  4. 4
    Nootropic peptide preparations: a review of mechanisms and clinical applications(2014)PubMed ↗

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Last updated: 2026-02-19