PT-141

PT-141, also designated bremelanotide, is a cyclic heptapeptide melanocortin receptor agonist. It is a metabolite of melanotan II, and its development followed the observation that the parent compound produced effects that were not explained by its intended melanocortin-1 receptor pigmentation activity.

The compound is a non-selective agonist across melanocortin receptors with principal activity at MC4R and MC3R. MC4R is expressed in the hypothalamus and is central to the regulation of both energy balance and sexual function — the receptor through which the compound's best-characterised effects run.

The mechanism is explicitly central rather than vascular. Unlike phosphodiesterase type 5 inhibitors, which act on peripheral smooth muscle and blood flow, PT-141 acts on hypothalamic circuits upstream of the peripheral response. This distinction is the reason the compound occupies its own pharmacological category rather than being a variation on existing agents.

Findings below are drawn from published preclinical and clinical work and are presented for research context only.

• Central mechanism. Activity at hypothalamic MC4R places the compound upstream of the peripheral vascular mechanisms targeted by phosphodiesterase inhibitors.

• Origin. The compound is a metabolite of melanotan II, identified after unexpected effects were observed with the parent molecule.

• Receptor breadth. Non-selective melanocortin agonism means MC1R-associated effects such as pigmentation and MC3R-associated effects on energy balance are also engaged.

• Clinical development. Bremelanotide has completed clinical development for hypoactive sexual desire disorder in premenopausal women, giving this compound a more substantial human dataset than most research peptides.

• Route history. An intranasal formulation was studied earlier in development; blood pressure effects at the doses used contributed to a change of route.

This section describes laboratory handling. It is not clinical guidance, and no safety claim for human or veterinary administration is made or implied.

• Supplied lyophilized. Reconstituted peptide solutions have materially shorter working stability than the dry powder — prepare working aliquots and avoid repeated freeze-thaw cycles.

• Handle as a research chemical of undetermined hazard. Use gloves, eye protection and a laboratory coat.

• Storage temperature and, where applicable, reconstitution conditions are stated on the item specification sheet and the lot Certificate of Analysis, which take precedence over general guidance.

• Dispose of unused material and consumables in accordance with the institutional chemical waste policy.

For laboratory research use only. Not for human or veterinary use. Not a drug, food, cosmetic or dietary supplement.

PT-141 is a cyclic heptapeptide melanocortin agonist acting principally at MC4R and MC3R. Its mechanism is central and hypothalamic, which distinguishes it categorically from peripheral vascular agents.

Unusually for a research peptide, it has completed clinical development for a defined indication, so the available human data are more substantial than the preclinical-only evidence typical of this catalog.

1. Sweeney P, Gimenez LE, Hernandez CC, Cone RD. Targeting the central melanocortin system for the treatment of metabolic disorders. Nat Rev Endocrinol. 2023;19(9):507-519.

2. Edinoff AN, Sanders NM, Lewis KB, Apgar TL, Cornett EM, Kaye AM, et al. Bremelanotide for Treatment of Female Hypoactive Sexual Desire. Neurol Int. 2022;14(1):75-88.

3. Clayton AH, Kingsberg SA, Portman D, Sadiq A, Krop J, Jordan R, et al. Safety Profile of Bremelanotide Across the Clinical Development Program. J Womens Health (Larchmt). 2022;31(2):171-182.

4. Mayer D, Lynch SE. Bremelanotide: New Drug Approved for Treating Hypoactive Sexual Desire Disorder. Ann Pharmacother. 2020;54(7):684-690.

5. Dhillon S, Keam SJ. Bremelanotide: First Approval. Drugs. 2019;79(14):1599-1606.

6. Bremelanotide. 2006.

7. Diamond LE, Earle DC, Heiman JR, Rosen RC, Perelman MA, Harning R. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist. J Sex Med. 2006;3(4):628-638.

8. Hedlund P. PT-141 Palatin. Curr Opin Investig Drugs. 2004;5(4):456-62.