N-Acetyl Semax Amidate: What It Is and How It Differs from Semax
N-acetyl Semax amidate is Semax with both ends capped: an acetyl group on the front methionine and an amide in place of the acid at the back, giving Ac-Met-Glu-His-Phe-Pro-Gly-Pro-NH2 (C39H54N10O10S, 855.0 g/mol, PubChem CID 172638603). The core seven-amino-acid sequence is unchanged; the caps are aimed at the enzymes that break Semax down from its ends. Semax itself has more than 230 PubMed records, including human studies, and published work on acetylated Semax shows the front cap changes how the peptide binds metal ions. This guide explains the chemistry, what has been published and how it compares with Semax.
Vistara Labs does not currently stock N-acetyl Semax amidate, but you can request it: contact us and we will source it for you. The closest product we sell is Semax itself: the ready-mixed Semax Nasal Spray (10 mg in 5 mL, about 28 sprays, or 20 mg in 10 mL, about 57 sprays, 350 mcg per spray) and the lyophilised Semax 10 mg vial.
Findings
- PubChem records N-acetyl Semax amidate as C39H54N10O10S, 855.0 g/mol, also listed as N-acetyl Semax and CAS 2920938-90-3 (PubChem CID 172638603).
- Unmodified Semax is C37H51N9O10S, 813.9 g/mol; the two caps add 41 g/mol (PubChem CID 9811102).
- In animal serum, aminopeptidases did most of the work of breaking Semax down; the aminopeptidase inhibitor bestatin blocked up to 66% of it (Potaman, Peptides, 1993).
- In human plasma, N-terminal acetylation and C-terminal amidation markedly prolonged the stability of a short peptide whose uncapped half-life was 22 seconds (Brinckerhoff, Int J Cancer, 1999).
- Acetylating Semax changed its copper-binding chemistry, and the free amino end of plain Semax was what protected cells from copper toxicity (Magrì, J Inorg Biochem, 2016).
What is N-acetyl Semax amidate?
The name describes two changes to Semax. “N-acetyl” means an acetyl group (CH3CO) is attached to the free amino group at the front of the chain, on methionine. “Amidate” means the carboxylic acid at the back, on the final proline, is replaced by an amide (CONH2).
The middle of the molecule stays the same: Met-Glu-His-Phe-Pro-Gly-Pro, the 4 to 7 fragment of adrenocorticotropic hormone (ACTH) joined to a Pro-Gly-Pro tail (Magrì, 2016). PubChem’s systematic name for the compound confirms both caps: an acetamido group on the first residue and a carbamoyl pyrrolidine, an amidated proline, on the last.
It is often shortened to NA-Semax-amidate or N-acetyl Semax. It should not be confused with Semax acetate, which is the ordinary salt form of unmodified Semax.
Why cap the ends of Semax?
Most enzymes that break down short peptides work from the ends. Aminopeptidases trim from the front (N-terminal) end, and carboxypeptidases and angiotensin-converting enzyme work from the back. In animal serum, aminopeptidases and angiotensin-converting enzyme were responsible for the major part of Semax breakdown (Potaman, 1993).
An acetyl group removes the free amino group that aminopeptidases recognise, and an amide removes the free acid at the other end. In human plasma, capping a short test peptide this way markedly prolonged its stability (Brinckerhoff, 1999). Researchers at the Institute of Molecular Genetics in Moscow, where much of the Semax research is published, have addressed the subject directly, in “Stability of Semax acetyl to proteolysis in various biological media” (Shevchenko, Dokl Biol Sci, 2013).
What has been published about N-acetyl Semax amidate?
PubMed indexes no paper under the name N-acetyl Semax amidate (search, October 2026). Published work covers the acetylated form, Ac-Semax:
- Metal binding, 2016. Acetylating the front of Semax changed the copper complex it forms, from a CuN4 to a CuN3O arrangement, and changed its redox behaviour. Unmodified Semax protected a neuroblastoma cell line from copper-induced toxicity and Ac-Semax did not, showing the free amino end does that job. Both forms bound zinc with comparable strength (Magrì, 2016).
- Proteolysis, 2013. Researchers at the Institute of Molecular Genetics in Moscow examined the stability of acetylated Semax in biological media (Shevchenko, 2013).
The human and mechanism research for this family is on Semax itself.
What does Semax research show?
- Stroke recovery, 2018. In 110 patients after ischaemic stroke, Semax raised plasma BDNF and improved final Barthel Index scores (Gusev, Zh Nevrol Psikhiatr Im S S Korsakova, 2018).
- Brain networks, 2018. In healthy volunteers, intranasal Semax enlarged the medial frontal part of the default mode network on resting-state fMRI compared with placebo (Lebedeva, Bull Exp Biol Med, 2018).
- BDNF mechanism, 2006. In an animal model, intranasal Semax raised BDNF protein in the basal forebrain within 3 hours, and basal forebrain membranes held specific Semax binding sites (Dolotov, J Neurochem, 2006).
Our Semax research overview and Semax and stroke recovery go deeper.
N-acetyl Semax amidate vs Semax: how do they differ?
| Semax | N-acetyl Semax amidate | |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Ac-Met-Glu-His-Phe-Pro-Gly-Pro-NH2 |
| Formula, weight | C37H51N9O10S, 813.9 g/mol | C39H54N10O10S, 855.0 g/mol |
| Front end | Free amino group | Acetyl cap |
| Back end | Free acid | Amide |
| Copper chemistry | CuN4 complex; protective in cell study | Acetylated form: CuN3O complex |
| Human studies | Stroke, brain imaging | None indexed |
| At Vistara Labs | Nasal spray and 10 mg vial | Sourced on request |
- Semax is the choice for protocols that need published reference points, and for metal-binding work, where its free amino end is the active part.
- N-acetyl Semax amidate suits stability and structure-activity work: comparing a fully capped Semax against the parent under the same enzymes or media.
A related variant, Adamax, uses an adamantane group at the back end instead of a simple amide.
Semax for research in Canada
Vistara Labs supplies the Semax Nasal Spray ready-mixed in sterile saline in a sealed metered pump that delivers 0.175 mL per press: 10 mg in 5 mL (about 28 sprays) or 20 mg in 10 mL (about 57 sprays), at 350 mcg per spray. The Selank + Semax Nasal Spray holds 10 mg of each in 10 mL. The lyophilised Semax 10 mg vial is the powder format. Orders ship from within Canada by Canada Post Xpresspost, with certificates on the lab reports page. See Buy Semax Nasal Spray in Canada for the full spray range.
Semax and its derivatives are supplied for laboratory research use only. The human studies above were clinical research using pharmaceutical preparations under medical supervision.
Frequently asked questions
What is N-acetyl Semax amidate?
It is Semax with an acetyl group on the front methionine and an amide at the back proline: Ac-Met-Glu-His-Phe-Pro-Gly-Pro-NH2, C39H54N10O10S, 855.0 g/mol (PubChem CID 172638603).
How is N-acetyl Semax amidate different from Semax?
The amino-acid sequence is the same. Semax has a free amino group at the front and a free acid at the back; N-acetyl Semax amidate caps both, which targets the enzymes that break Semax down from its ends.
Is N-acetyl Semax the same as Semax acetate?
No. N-acetyl Semax has an acetyl group bonded to the peptide chain. Semax acetate is unmodified Semax supplied as an acetate salt.
Has N-acetyl Semax amidate been studied?
PubMed indexes no paper under that name. Published work on acetylated Semax shows the acetyl cap changes its copper binding (2016), and Semax itself has human studies on stroke recovery and brain imaging.
Does Vistara Labs sell N-acetyl Semax amidate?
Vistara Labs does not currently stock N-acetyl Semax amidate, but you can request it: contact us and we will source it for you. Vistara Labs sells Semax as a ready-mixed nasal spray (10 mg or 20 mg, 350 mcg per spray) and as a 10 mg vial.
Product details from vistaralabs.ca, October 2026. Sources: Magrì A et al. 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. PMID 27586814. Shevchenko KV et al. Stability of Semax acetyl to proteolysis in various biological media. Dokl Biol Sci. 2013. PMID 23652441. Potaman VN et al. Degradation of ACTH/MSH(4-10) and its synthetic analog semax by rat serum enzymes: an inhibitor study. Peptides. 1993. PMID 8392718. Brinckerhoff LH et al. Terminal modifications inhibit proteolytic degradation of an immunogenic MART-1(27-35) peptide: implications for peptide vaccines. Int J Cancer. 1999. PMID 10495424. Gusev EI 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. PMID 29798983. Lebedeva IS et al. Effects of Semax on the Default Mode Network of the Brain. Bull Exp Biol Med. 2018. PMID 30225715. Dolotov OV et al. J Neurochem. 2006. PMID 16635254. PubChem. N-acetyl Semax amidate, CID 172638603; Semax, CID 9811102.
More on this: Buy Semax in Canada, How Long Does Semax Last? and Semax vs Selank.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
