Sable · Question
What is the difference between Selank and P21?
Selank is a synthetic heptapeptide analogue of tuftsin extended with Pro-Gly-Pro, developed at the Institute of Molecular Genetics in Russia and studied in neuropeptide research (peptide, MW about 751.9 g/mol).
Research use only. Not for human consumption. No health claims.
Last verified 2026-10-10
What is the difference between Selank and P21?
Selank is a synthetic heptapeptide analogue of tuftsin extended with Pro-Gly-Pro, developed at the Institute of Molecular Genetics in Russia and studied in neuropeptide research (peptide, MW about 751.9 g/mol).
Which is heavier, Selank or P21?
Selank has a molecular weight of about 751.9 g/mol and P21 about 578.7 g/mol (PubChem), so Selank is heavier by 173.2 g/mol, a ratio of 1.3. This means 1 mg of Selank contains 1,330 nmol versus 1,728 nmol for P21.
How many mg of P21 are equimolar to 1 mg of Selank?
1 mg of Selank (MW 751.9) is 1,330 nmol. The same number of moles of P21 (MW 578.7) weighs 0.7697 mg. Equimolar comparisons matter when testing two compounds side by side in the same assay.
Compare the molecular formulas of Selank and P21
PubChem lists Selank as C33H57N11O9 (751.9 g/mol) and P21 as C27H42N6O8 (578.7 g/mol). Selank is a peptide; P21 is a peptidomimetic. These formulas refer to the parent compounds without salt counter-ions.
A 10 mg vial of P21 equals how many mg of Selank in moles?
10 mg of P21 (MW 578.7) is 17.28 µmol. The same amount of Selank (MW 751.9) would weigh 12.993 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 5 mg vial of P21 equals how many mg of Selank in moles?
5 mg of P21 (MW 578.7) is 8.64 µmol. The same amount of Selank (MW 751.9) would weigh 6.496 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 5 mg vial of Selank equals how many mg of P21 in moles?
5 mg of Selank (MW 751.9) is 6.65 µmol. The same amount of P21 (MW 578.7) would weigh 3.848 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 10 mg vial of Selank equals how many mg of P21 in moles?
10 mg of Selank (MW 751.9) is 13.3 µmol. The same amount of P21 (MW 578.7) would weigh 7.697 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A CoA for every lot; each vial carries a printed lot number that matches it. Ask with the lot number and we send it.
Cite this
Research use only. Not for consumption. No health claims.
Plain
Sable Peptides. (2026). What is the difference between Selank and P21?. UK Research Peptide Reference. Retrieved 11 October 2026, from https://www.sablepeptides.co.uk/questions/compare/p21-vs-selank/#sqa-040729
APA
Sable Peptides. (2026, October 11). *What is the difference between Selank and P21?*. UK Research Peptide Reference. https://www.sablepeptides.co.uk/questions/compare/p21-vs-selank/#sqa-040729
BibTeX
@misc{sable_#sqa-040729_2026,
author = {{Sable Peptides}},
title = {{What is the difference between Selank and P21?}},
year = {2026},
howpublished = {\url{https://www.sablepeptides.co.uk/questions/compare/p21-vs-selank/#sqa-040729}},
note = {Accessed 11 October 2026. CC BY 4.0}
}Badge
<a href="https://www.sablepeptides.co.uk/ref"><img src="https://www.sablepeptides.co.uk/badge/ref.svg" alt="Data: UK Research Peptide Reference — Sable Peptides" width="220" height="40"></a>
Date modified: 2026-10-10