N-Acetyl Selank Amidate

01 · What it is

PubMed contains no paper about this compound. Not a study, not a chemistry note, not a stability measurement. The exact string “acetyl selank” is not even present in the database’s phrase index — searching for it returns the message that the quoted phrase is not indexed.

This is the emptiest file in the project. PEG-MGF at least matched five records that turned out to be about other molecules; N-Acetyl Semax Amidate has two chemistry papers about a partially matching modification. This compound has neither.

What the name claims. N-Acetyl Selank Amidate — sold as NA-Selank-Amidate or NASP — is described as Selank carrying an acetyl group on the N-terminus and an amide on the C-terminus. Selank itself is the heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro: the immunomodulatory tetrapeptide tuftsin ⁷ with the Pro-Gly-Pro tail that the same Moscow institute uses on both of its neuroactive peptides. So the product is a doubly modified version of an already modified fragment of an immune peptide.

The rationale offered is the standard one. Free termini are what exopeptidases recognise; capping both should extend half-life. That is sound chemistry and it is the whole of the argument.

What is actually known about capping these peptides. Only from the sister compound. N-terminal acetylation of Semax changes that peptide’s coordination of copper(II) and zinc(II) and its associated biological properties ⁵ — which establishes that acetylation is not pharmacologically inert. A 2013 report measured stability of acetylated Semax in biological media ², and PubMed carries no abstract for it, so its result is unavailable. Neither paper concerns Selank, and neither concerns amidation.

What is known about the parent is set out in its own guide, and one item from it belongs here: Selank potentiates diazepam in rats ⁶. A longer-lived version of a compound that potentiates benzodiazepines would potentiate them for longer. Nobody has studied that.

Nothing has been given to an animal. No pharmacology, no behaviour, no pharmacokinetics, no toxicology, no trial, in any species.

02 · Evidence at a glance

Evidence grade

Preclinical — a floor, not a finding. No study of this compound exists at any level

Claimed structure

Selank with N-terminal acetylation and C-terminal amidation

Parent compound

Selank: Thr-Lys-Pro-Arg-Pro-Gly-Pro — tuftsin plus Pro-Gly-Pro ^1,7

Indexed papers on this compound

0

Name in PubMed’s phrase index

Absent

Nearest relevant chemistry

N-terminal acetylation of Semax, a different peptide ^2,5

Papers on amidation of either peptide

0

In vitro studies

None

Animal studies

None

Human studies

None

Human subjects to date

0

Pharmacokinetics

None, in any species

Inherited concern from the parent

Selank potentiates diazepam in rats ⁶

Approval status

None, any jurisdiction

03 · Mechanism of action

Nothing is known about this compound’s mechanism. What follows is the chemistry of the modifications and the parent’s proposed pharmacology, each labelled as such.

What the two caps do

Aminopeptidases require a free α-amino group and carboxypeptidases a free α-carboxyl. Acetylation removes the first recognition feature and amidation the second. For a seven-residue peptide with no other protective features, this would ordinarily produce a substantial increase in plasma and tissue half-life.

That is the extent of what can be said with confidence, and it is a statement about peptide chemistry in general rather than about this molecule.

Why the caps may not be neutral here

Two specific reasons, beyond the general risk that a peptide’s termini are part of its pharmacophore.

First, acetylation is demonstrably not inert on the sister compound. It alters Semax’s metal coordination and, in the authors’ phrasing, its biological properties ⁵. There is no reason to assume the analogous modification is silent on Selank, and no experiment has checked.

Second, the C-terminal tripeptide. Both Moscow peptides end in Pro-Gly-Pro, and for Semax the tripeptide alone reproduces the parent’s headline transcriptional effect [see the Semax guide]. Amidating the C-terminus caps the free end of that tripeptide. Whether Pro-Gly-Pro liberation matters for Selank has never been tested — the parent has never been compared against Pro-Gly-Pro either.

The parent’s proposed mechanism, unresolved

Selank has no identified receptor. Its anxiolytic claim rests on changes in the expression of genes involved in GABAergic neurotransmission ⁴ rather than on binding data, together with effects on hippocampal synaptic activity and the diazepam potentiation ⁶. A derivative of a compound whose own target is unknown inherits that uncertainty entire.

The immune inheritance

Tuftsin is an immunostimulant released from immunoglobulin G ⁷. A protease-resistant version of a tuftsin derivative would sustain any immunological activity for longer than the parent, and no study in this file or the parent’s has measured immune parameters in a human after either compound.

04 · Key research findings

There are none for this compound. What follows is the adjacent evidence, labelled.

On acetylating one of these peptides. N-terminal acetylation of Semax modifies its ability to form complex species with Cu(II), with the amino-free form giving a redox-stable complex, and modulates the peptide’s chemical and biological properties ⁵.

The only substantive published result on any acetylated Moscow peptide. It is inorganic chemistry, it concerns Semax rather than Selank, and its message is that the modification changes things.

On stability of an acetylated form. A 2013 report examined stability of Semax acetyl to proteolysis in various biological media ². No abstract is indexed.

Cited as a title. The result — whether acetylation actually extended stability, and by how much — is not in the retrievable record for Semax, and has never been measured for Selank.

On the parent, for context only. Selank is indexed with one Russian-language clinical trial in anxiety disorders ³ and appears in a connectomic imaging study of 52 healthy participants ⁸. It alters GABAergic gene expression ⁴. It enhances diazepam’s anxiolytic effect in rats ⁶. It derives from tuftsin ^1,7.

None of this is evidence about the acetylated-amidated compound. It is here so a reader can see precisely what is borrowed when the parent’s results are offered for the derivative.

Contemporary mentions. Reviews list Selank among neuroactive peptides of interest ^9,10. Neither names the acetylated or amidated form.

05 · Evidence overview

06 · Safety profile

Animal data. None. No study in any species exists.

Human data. None. There is no reported human exposure to this compound at any dose, by any route, for any duration.

What is genuinely unknown. Everything about the compound itself, and four inherited questions worth naming. Whether it retains any of Selank’s activity, given that acetylation measurably changes the sister peptide’s chemistry ⁵. Its half-life — the sole reason the modification exists, unmeasured for this molecule and unavailable even for the acetylated sister compound ². What prolonged exposure to a benzodiazepine-potentiating substance does, since the parent potentiates diazepam in rats ⁶ and a protease-resistant version would do so over a longer window — a question with obvious relevance given that the compound is marketed for anxiety and benzodiazepines are prescribed for anxiety. And the immunological consequences of a longer-lived tuftsin derivative ⁷, unmeasured in any human for either compound.

There are no adverse event reports for this compound because there are no studies of it. That is not a safety record.

07 · US regulatory status

Current as of 6 September 2026. N-Acetyl Selank Amidate is not approved as a drug in the United States or any other jurisdiction and is not a controlled substance.

No marketing authorisation, investigational programme or regulatory assessment appears anywhere in the peer-reviewed record. The parent compound is described in Russian sources in terms consistent with registered clinical use ³; this guide does not characterise that registration, and in any case it would not extend to a chemically modified derivative.

Under the World Anti-Doping Code, substances not approved for human therapeutic use by any governmental regulatory health authority fall within class S0. Competitors should consult the current Prohibited List directly rather than rely on secondary summaries, including this one.

08 · Limitations of the evidence

1. There are no studies of this compound. Zero indexed papers. This guide contains no evidence about the molecule named at the top of it, and every reference below concerns either the parent compound or a different peptide.
2. The compound name is absent from PubMed’s phrase index. There is no published characterisation under the name on the label, and therefore no reference standard a purchaser could compare a product against.
3. The Preclinical grade is a floor. The rubric’s lowest tier describes in vitro and animal data. This compound has neither. It receives the lowest available grade because there is nowhere lower, and the grade should not be read as implying preclinical support exists.
4. Even the stability rationale is unverified. The one report that measured stability of an acetylated Moscow peptide has no indexed abstract ², and it concerns Semax rather than Selank.
5. Acetylation is known to change these molecules’ chemistry ⁵. Presenting it as a purely protective modification is not supported.
6. Amidation may cap the Pro-Gly-Pro tail that matters. For the sister compound the tripeptide alone reproduces the headline effect; whether Selank behaves the same way is untested, and amidation would block the analogous route.
7. Everything claimed rests on the parent, whose own human evidence is a single Russian-language clinical trial this project could not read ³, and which has no identified receptor.
8. The benzodiazepine interaction is inherited and unexamined ⁶. A stabilised derivative would extend it.
9. No study compares the modified and unmodified compounds in any assay, in any species.
10. Nothing is known about commercial material. No published analysis has examined the identity, purity or actual modification state of any product sold under this name.

09 · References

1. Kozlovskaya MM, Kozlovskii II, Val’dman EA, Seredenin SB. Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress. Neurosci Behav Physiol. 2003 Nov;33(9):853–860.

   PMID 14969422 ↗

2. Shevchenko KV, Nagaev IY, Andreeva LA, Shevchenko VP, Myasoedov NF. Stability of Semax acetyl to proteolysis in various biological media. Dokl Biol Sci. 2013 Mar;449:110–112. No abstract available.

   PMID 23652441 ↗

3. Medvedev VE, Tereshchenko ON, Kost NV, Ter-Israelyan AY, Gushanskaya EV, Chobanu IK, Sokolov OY, Myasoedov NF. [Optimization of the treatment of anxiety disorders with selank]. Zh Nevrol Psikhiatr Im S S Korsakova. 2015;115(6):33–40. Clinical trial. Russian.

   PMID 26356395 ↗

4. Volkova A, Shadrina M, Kolomin T, Andreeva L, Limborska S, Myasoedov N, Slominsky P. Selank administration affects the expression of some genes involved in GABAergic neurotransmission. Front Pharmacol. 2016 Feb 18;7:31.

   PMID 26924987 ↗

5. Magrì A, Tabbì G, Giuffrida A, Pappalardo G, Satriano C, Naletova I, Nicoletti VG, Attanasio F. Influence of the N-terminus acetylation of Semax, a synthetic analog of ACTH(4-10), on copper(II) and zinc(II) coordination and biological properties. J Inorg Biochem. 2016 Nov;164:59–69.

   PMID 27586814 ↗

6. Kasian A, Kolomin T, Andreeva L, Bondarenko E, Myasoedov N, Slominsky P, Shadrina M. Peptide Selank enhances the effect of diazepam in reducing anxiety in unpredictable chronic mild stress conditions in rats. Behav Neurol. 2017;2017:5091027.

   PMID 28280289 ↗

7. Siebert A, Gensicka-Kowalewska M, Cholewinski G, Dzierzbicka K. Tuftsin — properties and analogs. Curr Med Chem. 2017 Nov 17;24(34):3711–3727.

   PMID 28745220 ↗

8. Panikratova YR, Lebedeva IS, Sokolov OY, Rumshiskaya AD, Kupriyanov DA, Kost NV, Myasoedov NF. Functional connectomic approach to studying Selank and Semax effects. Dokl Biol Sci. 2020 Jan;490(1):9–11.

   PMID 32342318 ↗

9. Rahman OF, Lee SJ, Seeds WA. Therapeutic peptides in orthopaedics: applications, challenges, and future directions. J Am Acad Orthop Surg Glob Res Rev. 2026 Jan 2;10(1):e25.00236.

   PMID 41490200 ↗

10. Mavrych V, Shypilova I, Bolgova O. Therapeutic peptides in gerontology: mechanisms and applications for healthy aging. Front Aging. 2026 Apr 7;7:1790247.

    PMID 42021992 ↗