Sable · Question
What is the difference between PT-141 and TB-500?
PT-141 is a cyclic heptapeptide melanocortin receptor agonist, a metabolite-like analogue of Melanotan II with a C-terminal acid, used in melanocortin receptor research (cyclic peptide, MW about 1025.2 g/mol).
Research use only. Not for human consumption. No health claims.
Last verified 2026-10-10
What is the difference between PT-141 and TB-500?
PT-141 is a cyclic heptapeptide melanocortin receptor agonist, a metabolite-like analogue of Melanotan II with a C-terminal acid, used in melanocortin receptor research (cyclic peptide, MW about 1025.2 g/mol).
Which is heavier, PT-141 or TB-500?
PT-141 has a molecular weight of about 1025.2 g/mol and TB-500 about 889 g/mol (PubChem), so PT-141 is heavier by 136.2 g/mol, a ratio of 1.15. This means 1 mg of PT-141 contains 975.4 nmol versus 1,124.9 nmol for TB-500.
How many mg of TB-500 are equimolar to 1 mg of PT-141?
1 mg of PT-141 (MW 1025.2) is 975.4 nmol. The same number of moles of TB-500 (MW 889) weighs 0.8671 mg. Equimolar comparisons matter when testing two compounds side by side in the same assay.
Compare the molecular formulas of PT-141 and TB-500
PubChem lists PT-141 as C50H68N14O10 (1025.2 g/mol) and TB-500 as C38H68N10O14 (889 g/mol). PT-141 is a cyclic peptide; TB-500 is a peptide. These formulas refer to the parent compounds without salt counter-ions.
A 10 mg vial of PT-141 equals how many mg of TB-500 in moles?
10 mg of PT-141 (MW 1025.2) is 9.754 µmol. The same amount of TB-500 (MW 889) would weigh 8.671 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 TB-500 in moles?
5 mg of PT-141 (MW 1025.2) is 4.877 µmol. The same amount of TB-500 (MW 889) would weigh 4.336 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 10 mg vial of TB-500 equals how many mg of PT-141 in moles?
10 mg of TB-500 (MW 889) is 11.249 µmol. The same amount of PT-141 (MW 1025.2) would weigh 11.532 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 2 mg vial of TB-500 equals how many mg of PT-141 in moles?
2 mg of TB-500 (MW 889) is 2.25 µmol. The same amount of PT-141 (MW 1025.2) would weigh 2.306 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 5 mg vial of TB-500 equals how many mg of PT-141 in moles?
5 mg of TB-500 (MW 889) is 5.624 µmol. The same amount of PT-141 (MW 1025.2) would weigh 5.766 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 15 mg vial of TB-500 equals how many mg of PT-141 in moles?
15 mg of TB-500 (MW 889) is 16.873 µmol. The same amount of PT-141 (MW 1025.2) would weigh 17.298 mg. This equimolar conversion lets two compounds be compared at matched molar amounts in the same experiment.
A 20 mg vial of TB-500 equals how many mg of PT-141 in moles?
20 mg of TB-500 (MW 889) is 22.497 µmol. The same amount of PT-141 (MW 1025.2) would weigh 23.064 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 PT-141 and TB-500?. UK Research Peptide Reference. Retrieved 11 October 2026, from https://www.sablepeptides.co.uk/questions/compare/pt-141-vs-tb-500/#sqa-040508
APA
Sable Peptides. (2026, October 11). *What is the difference between PT-141 and TB-500?*. UK Research Peptide Reference. https://www.sablepeptides.co.uk/questions/compare/pt-141-vs-tb-500/#sqa-040508
BibTeX
@misc{sable_#sqa-040508_2026,
author = {{Sable Peptides}},
title = {{What is the difference between PT-141 and TB-500?}},
year = {2026},
howpublished = {\url{https://www.sablepeptides.co.uk/questions/compare/pt-141-vs-tb-500/#sqa-040508}},
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