What Is PT-141?

PT-141, also called bremelanotide, is a cyclic synthetic peptide studied as an agonist at melanocortin receptors. It belongs to the melanocortin family of peptides, related to fragments of alpha-melanocyte-stimulating hormone. This profile sets out the molecule, the receptor system it acts on, and the research it appears in, and makes no statement about use.

PT-141 arose from work on melanocortin peptides, the family related to melanocyte-stimulating hormone. It is a cyclic analogue within that family, designed so that part of the chain is joined into a ring, a structural choice common among peptides developed for stability and defined shape. The synthetic assembly of such peptides is outlined in how peptides are manufactured.

The melanocortin family comprises several related receptors, designated MC1 through MC5, which take part in a range of distinct signalling roles around the body. Peptides related to melanocyte-stimulating hormone act within this family, and PT-141 was developed as a cyclic analogue in that line of work, which is why it is studied as a tool for melanocortin-receptor pharmacology. The cyclic design reflects a common strategy for giving a peptide a constrained shape and greater resistance to breakdown, and it is part of what makes PT-141 a defined, reproducible subject for receptor study.

The defining structural feature of PT-141 is that it is cyclic: a portion of the peptide is closed into a ring rather than left as an open chain. Cyclisation gives a more constrained, defined shape and can change how a peptide resists breakdown. The material is handled as a lyophilised powder, as listed on the PT-141 product page; the general idea of a peptide and its bonds is in what is a peptide?

PT-141 is of interest as a melanocortin-receptor agonist, which makes it a tool for studying that receptor family in the laboratory. Its cyclic structure adds a second strand of interest, as an example of how constraining a peptide’s shape relates to its behaviour. The factual, claim-free framing this category requires is set out in our note on understanding research compounds.

Published work places PT-141 in melanocortin-receptor research, characterising how the cyclic analogue engages receptors in this family and how it behaves in laboratory systems. These describe the molecule in research settings only, with no implication about use. Other compounds studied in signalling research appear in the research catalogue.

A thread running through this work is how a cyclic analogue engages a family of related receptors, which makes PT-141 useful for asking how shape and receptor preference connect. Studies characterise the molecule across the family rather than at a single receptor, treating it as a defined structural subject and keeping their conclusions within the systems examined.

PT-141 is best understood as one cyclic analogue within the broader study of melanocortin receptors, and reading its literature calls for keeping observations tied to their studies. The PT-141 research overview takes up the receptor mechanisms and the limits of the evidence.

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