Sable · Question
What is the difference between Melanotan I and PT-141?
Melanotan I is a linear 13-residue alpha-MSH analogue used in melanocortin-1 receptor research (peptide, MW about 1646.8 g/mol).
Research use only. Not for human consumption. No health claims.
Last verified 2026-10-10
What is the difference between Melanotan I and PT-141?
Melanotan I is a linear 13-residue alpha-MSH analogue used in melanocortin-1 receptor research (peptide, MW about 1646.8 g/mol).
Which is heavier, Melanotan I or PT-141?
Melanotan I has a molecular weight of about 1646.8 g/mol and PT-141 about 1025.2 g/mol (PubChem), so Melanotan I is heavier by 621.6 g/mol, a ratio of 1.61. This means 1 mg of Melanotan I contains 607.2 nmol versus 975.4 nmol for PT-141.
How many mg of PT-141 are equimolar to 1 mg of Melanotan I?
1 mg of Melanotan I (MW 1646.8) is 607.2 nmol. The same number of moles of PT-141 (MW 1025.2) weighs 0.6225 mg. Equimolar comparisons matter when testing two compounds side by side in the same assay.
Compare the molecular formulas of Melanotan I and PT-141
PubChem lists Melanotan I as C78H111N21O19 (1646.8 g/mol) and PT-141 as C50H68N14O10 (1025.2 g/mol). Melanotan I is a peptide; PT-141 is a cyclic peptide. These formulas refer to the parent compounds without salt counter-ions.
A 5 mg vial of Melanotan I equals how many mg of PT-141 in moles?
5 mg of Melanotan I (MW 1646.8) is 3.036 µmol. The same amount of PT-141 (MW 1025.2) would weigh 3.113 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 10 mg vial of Melanotan I equals how many mg of PT-141 in moles?
10 mg of Melanotan I (MW 1646.8) is 6.072 µmol. The same amount of PT-141 (MW 1025.2) would weigh 6.225 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 10 mg vial of PT-141 equals how many mg of Melanotan I in moles?
10 mg of PT-141 (MW 1025.2) is 9.754 µmol. The same amount of Melanotan I (MW 1646.8) would weigh 16.063 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 5 mg vial of PT-141 equals how many mg of Melanotan I in moles?
5 mg of PT-141 (MW 1025.2) is 4.877 µmol. The same amount of Melanotan I (MW 1646.8) would weigh 8.032 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
More questions about melanotan-i
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 Melanotan I and PT-141?. UK Research Peptide Reference. Retrieved 11 October 2026, from https://www.sablepeptides.co.uk/questions/compare/melanotan-i-vs-pt-141/#sqa-040076
APA
Sable Peptides. (2026, October 11). *What is the difference between Melanotan I and PT-141?*. UK Research Peptide Reference. https://www.sablepeptides.co.uk/questions/compare/melanotan-i-vs-pt-141/#sqa-040076
BibTeX
@misc{sable_#sqa-040076_2026,
author = {{Sable Peptides}},
title = {{What is the difference between Melanotan I and PT-141?}},
year = {2026},
howpublished = {\url{https://www.sablepeptides.co.uk/questions/compare/melanotan-i-vs-pt-141/#sqa-040076}},
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