Reviewed & approved by Dr. Nova Reyes · Last checked 2026-10-26. ← Back to Evidence Library

N-Acetyl Semax and N-Acetyl Selank (amidate forms): what the evidence says

Name: N-Acetyl Semax and N-Acetyl Selank (amidate forms)
Creator: Dr. Nova Reyes
Published: 2026-10-26

At a glance

What it is: gray-market versions of two Russian nasal-spray peptides, Semax (Met-Glu-His-Phe-Pro-Gly-Pro) and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro), with an acetyl group added to the front end and sometimes an amide at the back end ("NA-Semax-Amidate," "N-Acetyl Selank Amidate"). Sellers claim the changes make them stronger and longer-lasting. ^R1

What the evidence says: a PubMed search for "N-acetyl semax" or "NA-Semax-Amidate" returned 0 papers. No trial is registered. The claimed benefits are unpublished. The parent drugs have Russian clinical data; see Semax and Selank.

Biggest risks: unknown for the modified forms. FDA lists semax and selank with immune-reaction and impurity concerns and little safety data. ^R2

Rating


Human Human evidence	None for N-acetyl or amidate forms · Parent compounds: small Russian trials ^{R3, R4, R5, R6}
Animal Animal / lab evidence	None for the modified forms · Parent compounds: rat and lab studies ^{R7, R1}
Regulatory	Not approved in the US · Semax and selank nominations withdrawn; FDA safety-risk notes still posted · WADA 2026: not named; likely S0 Caution ^{R2, R8}
Established human dose	None for the modified forms. Study details lists what parent-drug studies used

Evidence verdict: N-acetyl or amidate forms: No human or animal data in PubMed · Parent Semax and Selank: Limited (Russian trials), see their pages Card verdict: No human data (zero published studies on the N-acetyl or amidate forms; parent drugs Semax and Selank rated separately) Card note: No published data on these modified forms, see page

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: all parent-drug human data come from Russian institutes that developed the peptides (Institute of Molecular Genetics; Zakusov Institute of Pharmacology), mostly in Russian-language journals. Nothing independent exists for the modified forms.

What is it?

Adding an acetyl group or amide to a peptide's ends can slow breakdown by enzymes. Whether that is true here, and whether it changes the effect, has not been published. Related pages: Semax, Selank, Cerebrolysin, Dihexa.

Does it work?

Unknown Modified forms: no human, animal or lab study found.
Human Parent Selank: two Russian trials in about 60 patients each with anxiety or neurasthenia found effects similar to the benzodiazepines medazepam or phenazepam. ^{R4, R3}
Human Parent Semax: a Russian study of 110 stroke patients reported more BDNF and better recovery with Semax; not randomized per the abstract. UNVERIFIED design details. ^R5 An fMRI study in 52 healthy people found brain connectivity changes. ^R6
Animal Lab: both parents block enzymes that break down enkephalins. ^R1

Is it safe?

Unknown No safety data for the modified forms.
Human FDA (parents): possible immune reactions from clumping and impurities; FDA has little or no human safety data for semax or selank. ^R2

Gray-market "research use only" versions: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe. European authorities found Semax and Selank in seized products and noted they had not completed clinical trials outside Russia. ^R9 For a modified form with no reference standard, a buyer cannot easily confirm what is in the vial.

What we don't know

Unknown Whether the N-acetyl or amidate forms last longer or work differently
Unknown Any safety data for the modified forms
Unknown Independent replication of the parent-drug trials

Is it legal?

US (FDA): not approved. Semax and selank are listed under "nominated but withdrawn" on FDA's safety-risk page; neither, nor the modified forms, is on the 503A or 503B category lists. ^{R2, R10, R11}
Russia: the parent drugs are registered medicines there. UNVERIFIED not checked against the Russian state register.
Athletes: not named on the WADA 2026 list. UNVERIFIED likely covered by S0. ^R8

Study details

These are amounts researchers used, not recommendations. | Study | People / model | Route | Amount used | Follow-up | Reported | Citation | |---|---|---|---|---|---|---| | Zozulia 2008 (parent Selank) | 62 patients, anxiety/neurasthenia | Nasal Caution | UNVERIFIED not in abstract | 14 days Caution | Similar to medazepam | [PMID 18454096](https://pubmed.ncbi.nlm.nih.gov/18454096/) | | Panikratova 2020 (parents) | 52 healthy people | Per abstract, "injection" Caution route | Caution not in abstract | 20 min | Connectivity changes | [PMID 32342318](https://pubmed.ncbi.nlm.nih.gov/32342318/) |

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Kost NV, et al. Bioorg Khim. 2001. PMID 11443939
^R2 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R3 Medvedev VE, et al. Zh Nevrol Psikhiatr Im S S Korsakova. 2014. PMID 25176261
^R4 Zozulia AA, et al. Zh Nevrol Psikhiatr Im S S Korsakova. 2008. PMID 18454096
^R5 Gusev EI, et al. Zh Nevrol Psikhiatr Im S S Korsakova. 2018. PMID 29798983
^R6 Panikratova YR, et al. Dokl Biol Sci. 2020. PMID 32342318
^R7 Slominsky PA, et al. Dokl Biol Sci. 2017. PMID 28702721
^R8 WADA. The 2026 Prohibited List, S0. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
^R9 Vanhee C, et al. Drug Test Anal. 2020. PMID 31667971
^R10 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R11 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use N-Acetyl Semax and N-Acetyl Selank (amidate forms). Talk to a clinician you trust, especially if you take psychiatric or seizure medicines, are pregnant, or are a tested athlete. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).