What's on the label is the measured result — net peptide mass, not gross powder weight, plus RP-HPLC purity, on a lot-numbered COA for every batch.
Net peptide mass and RP-HPLC purity — a lot-numbered COA for every batch.
Net peptide mass + HPLC purity, per lot.
PCAC will review 7 peptides for the 503A bulks list, BPC-157, KPV, TB-500, MOTS-c, Emideltide, Semax, Epitalon. Read our briefing →
PCAC will review 7 peptides for the 503A bulks list. Read →
FDA PCAC reviews 7 peptides in July. Read →
Melanocortin-4 receptor agonist · approved for HSDD
PeptideXpo buyer fit
This PeptideXpo page is intentionally positioned for distributors, OEM buyers, and procurement teams comparing PT-141 (Bremelanotide) inside a wider peptide catalog. It is not trying to be the deepest single-molecule monograph; the differentiated intent is assortment planning, export-ready documentation, fill-size comparison, and whether this SKU belongs in a broader buyer program.
Overview
PT-141 (Bremelanotide, brand name Vyleesi) is a synthetic cyclic heptapeptide derived from the Melanotan II scaffold but engineered for preferential MC4R agonism over the other melanocortin receptors. PT-141's MC4R selectivity drives the molecule's clinical activity in the CNS, specifically downstream activation of dopaminergic pathways relevant to sexual-arousal physiology, without the broader pigmentation and cardiovascular effects that come with MC1R and MC3R activation. The molecule was approved by the FDA in 2019 as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women, delivered subcutaneously as an on-demand injection. PeptideXpo supplies PT-141 (Bremelanotide) as a lyophilized powder at ≥99.0% HPLC purity. The cyclic structure (lactam bridge in the same architectural pattern as MT-II's scaffold) requires careful synthesis and the analytical packet includes mass spec confirming the cyclized mass. Endotoxin (LAL) and microbial limits are recommended add-ons for any compounding or research workflow involving injectable administration. As an approved prescription drug, clinical use should reference the local approved finished product (Vyleesi or equivalents) rather than bulk active; bulk PT-141 is supplied for research and qualified compounding workflows only.
Specifications
Documentation available on request
Regulatory note
Approved as a prescription drug (Vyleesi) in the US for premenopausal HSDD; heavily regulated in most major jurisdictions. Sold only to qualified buyers with appropriate licensing in their jurisdiction. Order requires compliance review.
Frequently asked questions
PT-141 (Bremelanotide) is derived from the same general cyclic heptapeptide scaffold as Melanotan II but with substitutions that shift the receptor-affinity balance toward MC4R selectivity. MT-II is broadly active across MC1R, MC3R, MC4R, and MC5R; PT-141 is more concentrated at MC4R, with reduced activity at the other melanocortin receptors. The clinical consequence is that PT-141 drives the CNS-mediated effects (sexual arousal, satiety modulation) that MC4R agonism produces, without the strong pigmentation effects (MC1R) or cardiovascular effects that MT-II's broader profile produces. This MC4R-focused profile is what allowed PT-141 to advance through FDA approval as Vyleesi for HSDD.
Hypoactive Sexual Desire Disorder (HSDD) is the clinical designation for persistent and distressing low sexual desire. It's mechanistically distinct from the erectile-function-focused conditions targeted by PDE5 inhibitors (Viagra, Cialis, Levitra), which act peripherally on vascular smooth muscle. PT-141 acts centrally at MC4R in the CNS, modulating the dopaminergic pathways involved in sexual arousal at the central-nervous-system level rather than the peripheral-vascular level. This is the basis for PT-141's approval as Vyleesi for premenopausal HSDD in women, a use case where PDE5 inhibitors are not appropriate because the underlying biology is central rather than vascular. The dosing is on-demand subcutaneous injection roughly 45 minutes before anticipated activity.
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