0104 areas
Melanocortin receptor pharmacology
Binding and activation at melanocortin receptors, compared across related cyclic peptides.
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PT‑141 Peptide
A cyclic seven-residue melanocortin peptide, lyophilized. Sold in 10mg vials for laboratory research.
$34.50
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Lab sheet
PT-141, measured
Identity, purity and handling data for this compound, in one place. Tap an identifier to copy it.
Certificate of analysis
99.77%
HPLC purity, 10mg lot, reported 08/11/2026
Tested by Freedom Diagnostics, an independent lab. Search code Opti2608060835
View the certificateMolecular Formula
C50H68N14O10
Molar Mass
1025.2 g/mol
CAS Number
189691-06-3
Amino Acids
7
Form
Lyophilized powder
Full data sheet+
- Purity
- 99.77% by the published third-party report for the 10mg lot (Freedom Diagnostics, 08/11/2026)
- PubChem CID
- 9941379
- Structure
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
- Storage (lyophilized)
- -20 °C, sealed, light-protected
For research use only. Not for human consumption.
Overview
About PT-141
PT-141 is a small ring-shaped peptide that activates melanocortin receptors, a family of receptors involved in signaling in the brain and elsewhere. It is mainly used in research on the melanocortin-4 receptor (MC4R) in the central nervous system.
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It has seven residues, a molar mass of 1025.2 g/mol and CAS number 189691-06-3; the full structure and identifiers are in the lab sheet above. ORP supplies it as a lyophilized powder for in vitro and preclinical research only. It is not for human or animal use and is not intended to diagnose, treat, cure, or prevent any disease.
PT-141 is closely related to Melanotan II (MT-2), another cyclic melanocortin peptide. The two share the same ring and N-terminus; the difference is at the C-terminus, where PT-141 carries a free carboxylic acid and Melanotan II an amide. That one change is visible in their formulas: C50H68N14O10 for PT-141 against C50H69N15O9 for Melanotan II. Researchers use the pair to compare how small structural changes alter activity at melanocortin receptors.
Both peptides belong to the melanocortin family of research compounds, which act at melanocortin receptors (MC1R through MC5R). Research on PT-141 has focused on the melanocortin-4 receptor (MC4R) in the central nervous system and its role in hypothalamic and autonomic signaling, studied in receptor-binding assays, cell systems and animal models.
Identity is usually confirmed against the formula and a molar mass of about 1,025 by mass spectrometry, with purity by HPLC. ORP's 10mg PT-141 lot has a published third-party certificate of analysis from Freedom Diagnostics reporting 99.77% purity and a measured net content of 9.62 mg (reported 08/11/2026, accession 2608060835), shown on this page. Review the report against the product and lot before relying on it in your work.
Research context
What PT-141 is researched for
The areas where this compound appears in the published research literature.
Methodology
How PT-141 is studied
01Method 1Published PT-141 work uses receptor-binding and activation assays at melanocortin receptors, cell systems expressing those receptors, and animal models of…+
Published PT-141 work uses receptor-binding and activation assays at melanocortin receptors, cell systems expressing those receptors, and animal models of central melanocortin signaling.
02Method 2Identity is confirmed against the formula and molar mass by mass spectrometry, and purity by HPLC.+
Identity is confirmed against the formula and molar mass by mass spectrometry, and purity by HPLC. Each research protocol sets its own model, controls, concentrations and handling; this listing supplies the compound, not a protocol.
Storage protocols
PT-141 storage and handling
Lyophilized
-20°C
Long-term storage, as supplied
Reconstituted
2-8°C
In solution
Full handling protocol+
Store lyophilized PT-141 at -20°C, sealed and protected from light and moisture. Let the vial reach room temperature before opening so moisture does not condense on the powder.
Reconstituted peptide solutions are commonly held at 2-8°C and divided into single-use aliquots to avoid repeated freeze-thaw cycles. Validate the solvent, concentration and use period for your own protocol.
Ordering & shipping
Buy PT-141 online
PT-141 for sale from Optimum ReGen Peptides, a US research-peptide company with a storefront in Medford, Oregon. It is in stock, priced from $50. Every order ships 2-Day Priority Air, a $13 flat rate anywhere in the US, with tracking, or can be picked up at the store.
The current batch has a published third-party certificate of analysis, shown above. PT-141 is supplied as lyophilized powder, for laboratory and research use only, not for human consumption.
FAQ
PT-141 FAQ
What is PT-141?
PT-141 is a synthetic cyclic seven-residue peptide that acts at melanocortin receptors, used in research on central MC4R signaling. ORP sells it for laboratory research only, not for human or animal use.
What is the structure of PT-141?
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH: an acetylated norleucine attached to a six-residue ring closed between aspartic acid and lysine, with a free acid at the C-terminus. Molecular formula C50H68N14O10, molar mass 1025.2 g/mol.
What is the CAS number for PT-141?
189691-06-3. Its PubChem compound ID is 9941379.
What is the difference between PT-141 and Melanotan II?
They share the same ring and N-terminus. PT-141 ends in a free carboxylic acid where Melanotan II ends in an amide, so their formulas differ: C50H68N14O10 for PT-141 and C50H69N15O9 for Melanotan II. Both act at melanocortin receptors and are studied separately.
What receptors does PT-141 act on?
Melanocortin receptors, with research attention on the melanocortin-4 receptor (MC4R) in the central nervous system.
Is this PT-141 third-party tested?
Yes. The 10mg lot has a published certificate of analysis from Freedom Diagnostics, an independent lab, reporting 99.77% purity and 9.62 mg measured net content (reported 08/11/2026, accession 2608060835). It is linked on this page.
How should PT-141 be stored?
Keep the lyophilized powder at -20°C, sealed and protected from light and moisture. Reconstituted solutions are commonly kept at 2-8°C in single-use aliquots; validate the use period for your own protocol.
Is PT-141 for human use?
No. ORP sells PT-141 strictly as a laboratory research compound, not for human or animal consumption, and it is not intended to diagnose, treat, cure, or prevent any disease.
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