PT-141, also known as bremelanotide, is a synthetic cyclic heptapeptide — a ring-shaped chain of seven amino acids. It belongs to the melanocortin peptide family and was originally derived from the earlier research compound Melanotan II through metabolic modification. PT-141 was first described in the early 2000s. Its structure includes a lactam bridge — a cyclic bond formed between amino acid side chains — which constrains the molecule into a ring shape, a structural feature common among melanocortin peptides.

The compound has the molecular formula C₅₀H₆₈N₁₄O₁₀, a molecular weight of 1,025.2 g/mol, and a CAS number of 189691-06-3. It is supplied as a white to off-white lyophilized powder that dissolves readily in water. Structurally, PT-141 differs from its parent compound Melanotan II in that it lacks the linear N-terminal extension, making it a smaller, cyclized fragment. It is classified within the melanocortin receptor ligand family (MC1R through MC5R).

This product is strictly for research purposes only. Not approved for human or animal use.

PubChem Reference: View compound profile on NIH PubChem