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Comparison

N-Acetyl Semax Amidate vs Semax

Both are nootropic & neuro, so the meaningful differences are in kinetics, evidence and regulatory status.

On published evidence alone, Semax is the better documented of the two (preliminary human). That is a statement about the state of the literature, not a recommendation.

N-Acetyl Semax Amidate Semax
Class Nootropic & neuro Nootropic & neuro
Evidence Anecdotal only Preliminary human
Human trials None published ~8
Half-life ~1-2 hours ~30 minutes (intranasal)
Reported range 100-300 mcg 300-900 mcg
Frequency 1-2x daily intranasal 1-3x daily intranasal
Routes Intranasal, Subcutaneous Intranasal, Subcutaneous
FDA approved No No
Research use only Yes Yes
Banned in sport No No
Studied for Cognitive enhancement research, Focus and motivation Cognitive enhancement research, Stroke recovery, Optic nerve conditions
Reported side effects Nasal irritation, Overstimulation, Headache, Irritability Nasal irritation, Headache, Overstimulation, Irritability

N-Acetyl Semax Amidate

N-acetyl semax amidate adds an acetyl group to the N-terminus and an amide to the C-terminus of Semax. Both modifications are standard medicinal-chemistry approaches to slowing exopeptidase degradation, and they plausibly extend duration and improve membrane permeability. The widely repeated claim that it is several times more potent than Semax traces to vendor marketing rather than to any published comparative study, and the page should say so.

Semax

Semax is an analog of adrenocorticotropic hormone fragment 4-10, extended with proline-glycine-proline to resist enzymatic degradation. The modification removes hormonal activity at the adrenal cortex while preserving central effects, which include increased expression of brain-derived neurotrophic factor and its receptor TrkB, and modulation of dopaminergic and serotonergic transmission. It is on the Russian essential medicines list for stroke and cognitive disorders.

N-Acetyl Semax Amidate vs Semax: common questions

What is the difference between N-Acetyl Semax Amidate and Semax?

Both are nootropic & neuro. N-Acetyl Semax Amidate: An acetylated and amidated Semax variant marketed as more potent and longer lasting. The potency claims are not from published human work. Semax: A heptapeptide ACTH fragment analog used in Russia for stroke and cognitive indications, with no corticotropic activity.

Which has stronger evidence, N-Acetyl Semax Amidate or Semax?

Semax has the stronger evidence base (preliminary human, about 8 human studies) compared with N-Acetyl Semax Amidate (anecdotal only).

Are N-Acetyl Semax Amidate and Semax FDA approved?

Neither is FDA approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 172638603) ↗ · structure, identifiers, synonyms
  2. FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
  3. PubChem compound record (CID 9811102) ↗ · structure, identifiers, synonyms
  4. CAS Registry Number 80714-61-0 ↗ · chemical identity

Published literature

  1. Rahman OF, Lee SJ, Seeds WA. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.J Am Acad Orthop Surg Glob Res Rev 2026.PubMed 41490200 · doi:10.5435/JAAOSGlobal-D-25-00236
  2. Tarasov VV, Kudryashov NV, Chubarev VN, et al.. Pharmacological Aspects of Neuro-Immune Interactions.Curr Pharm Des 2018.PubMed 28875850 · doi:10.2174/1381612823666170829135115
  3. Sudakov KV. [Evolution of the stress concept].Vestn Ross Akad Med Nauk 2008.PubMed 19140465
  4. Gusev EI, Martynov MY, Kostenko EV, et al.. [The efficacy of semax in the tretament of patients at different stages of ischemic stroke].Zh Nevrol Psikhiatr Im S S Korsakova 2018.PubMed 29798983 · doi:10.17116/jnevro20181183261-68
  5. Vyunova TV, Medvedeva EV, Andreeva LA, et al.. [POSSIBLE ROLE OF TRANSTHYRETIN IN THE BIOLOGICAL MECHANISM OF THE REGULATORY PEPTIDE NEUROPROTECTION.].Mol Gen Mikrobiol Virusol 2016.PubMed 30383932
  6. Giri S, Chandra P. Modulation of neuropathological pathways by bioactive peptides and proteins/polypeptides: Targeting oxidative stress in neurodegenerative diseases.Neuropeptides 2025.PubMed 41004910 · doi:10.1016/j.npep.2025.102563
  7. Umnov RS, Lin'kova NS, Khavinson VKh. [Neuroprotective effects of peptides bioregulators in people of various age].Adv Gerontol 2013.PubMed 24738258
  8. Liapina LA, Pastorova VE, Obergan TIu, et al.. [Comparison of anticoagulant effects of regulatory proline-containing oligopeptides. Specificity of glyprolines, semax, and selank and potential of their practical application].Izv Akad Nauk Ser Biol 2006.PubMed 16634437
  9. Ilina AR, Popovich IG, Ryzhak GA, et al.. [Prospects for use of short peptides in pharmacotherapeutic correction of Alzheimer's disease.].Adv Gerontol 2024.PubMed 38944767
  10. Spirin NN, Fedorov VN, Vdovichenko VP. [Place of oligopeptide H-Met-Glu-His-Phe-Pro-Gly-Pro-OH in the therapy and rehabilitation of patients with ischemic stroke].Zh Nevrol Psikhiatr Im S S Korsakova 2024.PubMed 39166935 · doi:10.17116/jnevro202412408256

Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.

Read this first This page compares published reference data. It is not medical advice and not a recommendation to use either compound. Several compounds documented on this site are not approved for human use.