Bottom line
N-Acetyl Semax Amidate is a chemically modified variant of Semax bearing N-terminal acetylation and C-terminal amidation, intended to improve metabolic stability and blood-brain barrier penetration. It is not an approved drug in any jurisdiction and has no published human clinical trials. The scientific literature base is limited to animal studies. The compound is distinct from Semax (an approved medicine in Russia) and should not be assumed equivalent in safety, efficacy, or pharmacokinetics.
Identity and composition
| Field | Verified information |
|---|---|
| Preferred name | N-Acetyl Semax Amidate |
| Key aliases | NA-Semax-A, Acetyl-Semax-Amidate, Ac-MEHF-PGP-NH₂ |
| Molecular/sequence identity | Ac-L-Met-L-Glu-L-His-L-Phe-L-Pro-L-Gly-L-Pro-NH₂ |
| Modifications/form | N-terminal acetyl cap; C-terminal amidation; both termini blocked |
| Stable identifiers | CAS 2920938-90-3 (related); no DrugBank or UNII assigned; PubChem CID: 172638603 |
| Identity caveats | Not equivalent to Semax — terminal modifications alter PK/PD profile; the CAS entry is broadly associated and cross-referencing is uncertain; no regulatory body has reviewed this exact entity |
Development and approval status
| Jurisdiction | Status and indication | Product/source | As of |
|---|---|---|---|
| FDA (US) | Not approved | — | 2026-08 |
| EMA (EU) | Not approved | — | 2026-08 |
| Russia | Not approved as a separate entity | — | 2026-08 |
| Registers reviewed | No FDA-approved product or EMA-authorized medicine identified; status elsewhere requires a current national-register check | — | 2026-08 |
Mechanism and pharmacology
No published mechanism-of-action studies specific to the amidated form were identified at the time of search. By analogy to Semax, it may modulate melanocortin receptors and upregulate neurotrophins, but the terminal modifications alter receptor interaction, metabolism, and distribution. The claimed improved stability is based on general medicinal-chemistry principles rather than compound-specific published data.
Evidence by claim
| Claim/indication | Stage | Grade | Best human evidence | Main result | Important limitations |
|---|---|---|---|---|---|
| Nootropic / cognitive enhancement | Research chemical | E | None | No human data; extrapolation from Semax only | No compound-specific human trials |
| Improved stability vs Semax | Mechanistic hypothesis | E | Terminal modifications make altered stability plausible | No direct quantitative result established | No peer-reviewed comparative PK study identified |
Key studies
No published human studies were identified for N-Acetyl Semax Amidate specifically. Animal and in vitro data are proprietary, pre-publication, or held by research-chemical suppliers without independent peer review.
Dose and administration evidence
No approved labeled regimen
No established or recommended human dose.
Studied regimens (not recommendations)
No published human dose data.
What is not established
Any safe or effective human dose
Pharmacokinetics in any species outside limited animal data
Difference in clinical effect from Semax
Manufacturing consistency across suppliers
Safety
Established label risks
No regulatory safety assessment exists.
Human-study signals
No human data available.
Unknowns and product-quality risks
All safety dimensions are unknown: acute toxicity, chronic toxicity, mutagenicity, reproductive toxicity, drug interactions, and immunogenicity. Products sold for research use lack regulatory oversight, sterility assurance, identity verification, and dose consistency. Reports of adulteration and mislabelling are endemic in the research chemical market.
Interactions and special populations
No data exist. All interactions and special-population considerations are unknown.
Regulatory, compounding, and sport notes
WADA: not specifically listed; may be prohibited under category S0 (non-approved substances) — athletes should verify
US DEA: not scheduled
Not identified on the FDA 503A bulks list searched for this review; other compounding and pharmacy-law questions are jurisdiction- and product-specific
No registered manufacturer or pharmaceutical product
Evidence gaps
Zero published human trials of any design
No peer-reviewed pharmacokinetic or pharmacodynamic data specific to the amidated form
No regulatory filings anywhere
Safety profile completely uncharacterised
No independent chemical reference standard available
Search notes
Databases and registries: PubMed, PubChem, CAS Scifinder, ClinicalTrials.gov, Google Scholar
Search terms: N-Acetyl Semax Amidate, NA-Semax-A, acetylated semax amidated
Last searched: 2026-08-06
Inclusion emphasis: compound-specific human or animal data; regulatory records
Sources
PubChem. N-Acetyl Semax Amidate exact-name record (CID 172638603). https://pubchem.ncbi.nlm.nih.gov/compound/172638603
CAS 2920938-90-3. https://commonchemistry.cas.org/detail?cas_rn=2920938-90-3
Global Substance Registration System (GSRS). https://gsrs.ncats.nih.gov/
Vendor listings (e.g., Peptide Sciences, Limitless Biotech) — document market presence but not safety or efficacy