Selank has a label, in Russia; N-acetyl Selank amidate has a sales category. The amidate is Selank with both ends of the chain capped, sold on the promise that it lasts longer, and the dosage figures attached to it are Selank's registered nasal regimen copied across. This page sets out what is on record for each molecule (searches run 2026-11-12), traces the borrowed figures to their source, shows how much heavier the amidate is per molecule, and works the units for the 5 and 10 mg vials. It reports; it suggests no amount.
Selank's own label, trials and figures are on the Selank dosage page, and its water arithmetic, including the volume that reproduces the registered strength, on Selank reconstitution. The parallel case for the other capped Russian peptide is NA-Semax amidate. Any vial and water volume can be worked in the NA-Selank amidate calculator.
Two caps on a seven-residue chain
Selank is seven amino acids: the four-residue immune peptide tuftsin (Thr-Lys-Pro-Arg) with a Pro-Gly-Pro tail added to slow its breakdown. It is registered in Russia as a nasal drop, held and made by Peptogen in Moscow (register entry as recorded on this site's Selank page). The amidate adds two more protections: an acetyl group on the threonine at the start and an amide in place of the acid group on the final proline. Both are standard ways of making a peptide's ends harder for enzymes to trim.
| Selank | N-acetyl Selank | N-acetyl Selank amidate | |
|---|---|---|---|
| PubChem record (read 2026-11-12) | CID 11765600 | CID 133082488 | none |
| Formula | C33H57N11O9 | C35H59N11O10 | C35H60N12O9 (by arithmetic) |
| Molecular weight | 751.9 | 793.9 | 792.9 (by arithmetic) |
| Registered product | Russian 0.15% nasal drops | none | none |
One detail in the PubChem record is worth knowing before copying from it. The record's short-form synonym reads "AC-THR-LYS-PRO-ARG-GLY-PRO", six residues, while its drawn structure — and its formula — have seven, with prolines in positions 3, 5 and 7. The structure is right and the short name has dropped a proline. A certificate of analysis that matches the six-residue name would describe a different peptide; Medibact's NA-Selank amidate guide covers the mass a certificate should show for the real molecule.
What the record holds
| Where | Search, 2026-11-12 | What came back |
|---|---|---|
| PubMed | "acetyl selank" OR "selank amidate" OR "N-acetylselank" | 2 records, both one Moscow rat study of plain Selank (300 mcg/kg, compared with piracetam), in Russian (2002) and English (2003) |
| PubMed | "selank" | 137 records — the literature of the plain peptide |
| ClinicalTrials.gov | "selank" | 10 records; none studies Selank (magnetic stimulation, epilepsy, dyslexia and similar studies matched on the letters) |
| DailyMed | "selank" | 0 labels |
| PubChem | "N-acetyl selank amidate" | no compound |
So for the amidate there is a chemical description and nothing else. For plain Selank there is a registration and a literature, almost entirely Russian.
Where the circulating figures come from
The Russian label for Selank 0.15% gives its regimen in drops: 2 drops into each nostril, 3 times a day, for 14 days, repeatable after one to three weeks. It states no microgram figure. At the conventional 20 drops per millilitre, one drop of 1.5 mg/mL solution is 75 mcg, so the regimen is 300 mcg per administration and 900 mcg a day — figures that rest on the drop-size convention, as set out on the Selank page.
Vendor pages recorded on this site's peptide dosage chart on 2026-09-18 gave the amidate 200 to 600 mcg per dose, intranasally or by injection, one to three times a day, or 600 to 900 mcg a day in 14-day cycles. The 900 mcg and the 14 days are the Selank label's. The injected route has no Selank study behind it either: the registered product is a nasal drop. The chain is therefore a label for one molecule, converted to micrograms with an assumption about drop size, then attached to a second molecule and to a route the label does not describe.
Equal micrograms, fewer molecules
The amidate is heavier per molecule, so a microgram figure copied from Selank describes about 5.5% fewer molecules of it. The factor is 792.9 ÷ 751.9 = 1.0545.
| Selank amount | Molecules | Amidate mass with the same molecule count |
|---|---|---|
| 75 mcg (one drop, at 20 drops/mL) | 100 nmol | 79 mcg |
| 300 mcg (one administration on the label regimen) | 399 nmol | 316 mcg |
| 900 mcg (one day on the label regimen) | 1.20 µmol | 949 mcg |
The arithmetic is this site's. The gap is small beside the uncertainty in a drop's volume, and it is the only quantitative relation between the two molecules that can be stated without a study.
Units per vial
Vials are listed at 5 and 10 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 | 600 mcg |
|---|---|---|---|---|---|
| 5 mg in 1 mL | 5,000 | 50 | 4 units | 6 | 12 |
| 5 mg in 2 mL | 2,500 | 25 | 8 units | 12 | 24 |
| 5 mg in 3 mL | 1,667 | 16.7 | 12 units | 18 | 36 |
| 5 mg in 3.33 mL (Selank's 1.5 mg/mL) | 1,500 | 15 | 13.3 units | 20 | 40 |
| 10 mg in 1 mL | 10,000 | 100 | 2 units | 3 | 6 |
| 10 mg in 2 mL | 5,000 | 50 | 4 units | 6 | 12 |
| 10 mg in 3 mL | 3,333 | 33.3 | 6 units | 9 | 18 |
A 5 mg vial holds about 16 portions of 300 mcg and a 10 mg vial about 33, whatever the water. Readings of two or three units are where syringe error matters most; the scale is explained on insulin syringe units, and the general conversion on mcg to units. Selank and Semax are often discussed together; the reported combination is on Selank + Semax.
What is not established
- Any study of the amidate in people or animals, at any dose or by any route.
- Whether capping the ends lengthens its action, and by how much.
- Whether a microgram of the amidate does what a microgram of Selank does.
- Any figure for injected Selank, capped or not: the registered product is nasal.
Neither Selank nor its capped forms has a US label (DailyMed, 2026-11-12). A clinician is the person to discuss anxiety or sleep treatment with.