N-acetyl Semax amidate is sold as a stronger, longer-lasting version of Semax, the Russian nasal peptide, and it is searched mostly for one thing: how much. The honest answer is that no primary document gives a figure for this molecule. There is no clinical trial, no registered study and no label; the dosing that circulates is Semax dosing, carried across. This page records that absence with the searches that establish it (all run 2026-11-02), sets out what the borrowed Semax figures are, shows how the two molecules compare by weight, and does the unit arithmetic for the vials in circulation. It reports; it suggests no amount.
The figures for plain Semax, from the Russian registrations and trials, are on the Semax dosage page; the water arithmetic for its vials is on Semax reconstitution, and any vial and volume of this compound can be worked in the NA-Semax amidate calculator.
Two end-caps on a known peptide
Semax is seven amino acids, Met-Glu-His-Phe-Pro-Gly-Pro: a fragment of adrenocorticotropic hormone with a Pro-Gly-Pro tail added. The amidate adds an acetyl group to the first residue and replaces the last residue's acid group with an amide. Both changes are common ways of protecting a peptide's ends from enzymes that trim them. PubChem's record (CID 172638603) gives the formula C39H54N10O10S and a molecular weight of 855.0 g/mol, against 813.9 for Semax (CID 9811102). Its CAS registry number, 2920938-90-3, is a recent assignment; the molecule is a newer catalogue item than Semax, not a revived old drug.
What the record holds
| Where | Search, 2026-11-02 | What came back |
|---|---|---|
| PubMed | "N-acetyl semax", "acetyl semax", "semax amidate", "Ac-Semax", "N-Ac-Semax" | 8 records; 2 about the peptide, both laboratory work on acetylated Semax; no human study |
| ClinicalTrials.gov | "semax" | 0 studies |
| DailyMed | "semax" | 0 labels |
| PubChem | "N-acetyl semax amidate" | CID 172638603, 855.0 g/mol |
The two laboratory papers are small. A 2013 note from the Institute of Molecular Genetics of the Russian Academy of Sciences in Moscow reports on the stability of acetylated Semax to proteolysis in biological media (PMID 23652441); PubMed indexes its title but no abstract, so its figures are not reported here. A 2016 Italian study (PMID 27586814) found that acetylation changed how Semax binds copper and that the acetylated form, unlike plain Semax, did not protect nerve-like cells in a dish from copper toxicity; zinc handling was unchanged. Neither abstract describes the amidated molecule sellers list, and neither gives a dose for anyone.
The absence is the finding, and it is unusual only in degree. For plain Semax there is at least a registration and a clinical literature, almost all of it Russian. For the amidate there is a chemical record and a sales category.
Where the circulating figures come from
The pages that answer "N-acetyl Semax amidate dosage" do not cite a study of it. The clearest of them, a telehealth blog page dated 12 June 2026, describes intranasal use of "a few hundred micrograms" once or twice daily and says in the same passage that this is drawn from Russian Semax dosing and user reports rather than Western trials. Vendor pages recorded on this site's dosage chart on 2026-09-18 put numbers on it: 200 to 600 mcg a day by injection or nasally, or 400 to 900 mcg a day nasally split into two or three amounts, with no study cited. That is the chain: a figure for Semax, attached to a different molecule, on the strength of an expectation that the end-caps make it last longer. No document found tests that expectation.
The Semax figures being borrowed are, briefly: registered nasal solutions at 0.1% and 1%; about 50 mcg per drop at 0.1% and 500 mcg at 1%; 6,000 mcg a day in a 2018 stroke-rehabilitation study; 12 to 18 mg a day in acute stroke in 1997 — each sourced and dated on the Semax dosage page. How plain Semax and Selank, the related Russian peptide, compare is on Semax vs Selank.
Equal micrograms, fewer molecules
Because the amidate is heavier per molecule, a microgram figure copied from Semax describes slightly fewer molecules of it. The factor is 855.0 ÷ 813.9 = 1.0505.
| Semax amount | Molecules | Amidate mass with the same molecule count |
|---|---|---|
| 50 mcg (one 0.1% drop) | 61 nmol | 53 mcg |
| 300 mcg | 369 nmol | 315 mcg |
| 600 mcg | 737 nmol | 630 mcg |
| 6,000 mcg (2018 rehabilitation figure) | 7.37 µmol | 6,303 mcg |
The 5% gap is smaller than the error of most measuring methods discussed below, so it matters less than it looks. It is listed because it is the only quantitative relationship between the two molecules that can be stated without a study: what one molecule of the amidate does compared with one of Semax has never been measured.
The arithmetic per vial
Vials are listed in this site's calculator data at 5, 10 and 30 mg. Concentration is the vial's micrograms divided by the water; one unit on a U-100 syringe is 0.01 mL.
| Vial and water | mcg/mL | mcg per unit | 200 mcg | 300 mcg | 500 mcg | 600 mcg |
|---|---|---|---|---|---|---|
| 5 mg in 1 mL | 5,000 | 50 | 4 units | 6 | 10 | 12 |
| 5 mg in 2 mL | 2,500 | 25 | 8 | 12 | 20 | 24 |
| 10 mg in 1 mL (1%) | 10,000 | 100 | 2 | 3 | 5 | 6 |
| 10 mg in 2 mL | 5,000 | 50 | 4 | 6 | 10 | 12 |
| 10 mg in 5 mL | 2,000 | 20 | 10 | 15 | 25 | 30 |
| 10 mg in 10 mL (0.1%) | 1,000 | 10 | 20 | 30 | 50 | 60 |
| 30 mg in 3 mL (1%) | 10,000 | 100 | 2 | 3 | 5 | 6 |
At the 1% strength the amounts in circulation sit at two to six units, between the low marks of a syringe, where a half-unit misreading is an error of 8 to 25%. The insulin syringe units page shows the 30-, 50- and 100-unit barrels. Most of the circulating figures describe nasal use, where the dose is set by a spray or a drop rather than a syringe; a drop's volume depends on the dropper, and the conventional 20 drops per millilitre is a convention, not a measurement of any particular bottle. A 30 mg vial holds a hundred 300 mcg amounts at any water volume; the water decides only how they read.
What this page does not do
It states no amount and no schedule for anyone. It reports that no primary source states a dose for this molecule, shows where the circulating figures come from, and works the arithmetic. The compound is covered in Medibact's NA-Semax amidate guide; the general mixing procedure is on Medibact's how to reconstitute peptides page. Decisions about administering anything belong with a clinician.
Sources and dates
Opened 2026-11-02: PubChem CIDs 172638603 (N-acetyl Semax amidate, formula, weight, synonyms incl. CAS 2920938-90-3) and 9811102 (Semax); PubMed search for the five name variants (8 records); PubMed records for Shevchenko KV et al., Dokl Biol Sci 2013;449:110-2 (PMID 23652441, title only) and Magrì A et al., J Inorg Biochem 2016;164:59-69 (PMID 27586814, abstract); ClinicalTrials.gov API search "semax" (0); DailyMed SPL search "semax" (0); trimrx.com, "N-Acetyl Semax Amidate dosing protocol", published and updated 2026-06-12. Carried from this site's Semax pages with their read dates: the registered strengths, per-drop figures and trial amounts (2026-09-20) and the FDA advisory-committee record (2026-09-24). Molecule-count, concentration and unit arithmetic by this site. Corrections go to the contact page.