What Is PT-141?

Overview

PT-141 is the catalog designation for bremelanotide, a synthetic cyclic heptapeptide lactam described in the peer-reviewed literature as a non-selective agonist at the melanocortin receptor family.[1] Molinoff and colleagues published the original characterization of the compound as a melanocortin agonist in Annals of the New York Academy of Sciences.[1]

The molecule derives from the melanotropin structure-activity programme conducted at the University of Arizona, reviewed by Hadley and Dorr, which produced a series of superpotent α-MSH analogues including Melanotan II.[2] Bremelanotide is the deaminated derivative of that parent compound, carrying a C-terminal free acid where Melanotan II carries an amide — a single terminal change that alters the receptor-engagement profile while retaining the cyclic scaffold.[1][2]

Why the compound appears in the literature

Melanocortin receptors are a five-member family of class A G-protein-coupled receptors with distinct tissue distributions. Because bremelanotide engages several of these subtypes rather than one, it is used in receptor pharmacology as a non-selective tool ligand — typically alongside subtype-selective antagonists — to separate the contributions of individual melanocortin receptors in a given model system.[5][7] Van der Ploeg et al. established MC4R as the receptor subtype of interest for centrally mediated melanocortin pharmacology, and Cone and colleagues have reviewed the central melanocortin system in energy homeostasis.[3][6]

Regulatory status, reported factually

A pharmaceutical formulation of bremelanotide received U.S. FDA approval in 2019; Dhillon and Keam summarized that approval in Drugs.[13] That approval attaches to a specific manufactured pharmaceutical product under defined clinical conditions. The research-grade material supplied here is not that product, and nothing on this page describes or implies a clinical use for it.

A note on the published record

Investigators working with this compound should be aware that the bremelanotide clinical literature contains flagged records. One randomized trial of the compound was subsequently retracted, and a second study by the same author group carries a formal Expression of Concern issued by The Journal of Urology in 2023.[23] Separately, Spielmans published a re-analysis of the phase 3 programme contesting the magnitude of the reported effects.[22] Neither retracted nor Expression-of-Concern-flagged studies are cited as evidence anywhere on this page.

Research framework

Within the melanocortin research domain, PT-141 is most directly compared with Melanotan II for the amide-versus-free-acid terminal distinction and with KPV for the receptor-engagement versus PepT1-uptake distinction. The compound is supplied here strictly as a research reference standard for in vitro and animal-model investigation, and is not intended for human or veterinary use.