PT-141

PT-141, bremelanotide and Vyleesi are three names for the same molecule, and that nomenclature is the first thing to get straight before reading anything else online about it. PT-141 is the research-chemical name used in the original Palatin Technologies development programme. Bremelanotide is the international nonproprietary name (INN). Vyleesi is the AMAG (now Cosette Pharmaceuticals) brand name for the FDA-approved subcutaneous-injection product. Online vendors and forum posts use the three terms interchangeably, and the distinction matters mainly for sourcing context: 'Vyleesi' carries a regulated FDA-approved product behind the name, 'PT-141' as a research-vial label does not.

The molecule itself is a cyclic seven-amino-acid analogue of alpha-MSH, the natural melanocyte-stimulating hormone derived from the proopiomelanocortin (POMC) precursor. The cyclic structure, closed by a lactam bridge between the aspartate side chain at position 2 and the lysine side chain at position 7, was designed for metabolic stability and receptor selectivity. Bremelanotide acts as a non-selective agonist of the melanocortin receptor family, with its strongest action at MC4R and MC3R, which are expressed in the brain and involved in sexual-desire and arousal circuitry. Its action at MC1R, the receptor on skin melanocytes, accounts for the focal-hyperpigmentation side effect.

The compound has an unusual development history. Palatin Technologies licensed melanotan II from the University of Arizona in the 1990s and synthesised bremelanotide as a related molecule. The original clinical programme tested intranasal bremelanotide for erectile dysfunction in men and for female sexual dysfunction in women. Those trials were halted by the FDA in 2007 because of increases in blood pressure observed in clinical-trial subjects, and Palatin stopped developing the intranasal formulation in 2008. Bremelanotide then re-emerged as a subcutaneous-injection programme for hypoactive sexual desire disorder (HSDD) in premenopausal women, at a lower per-dose exposure than the earlier intranasal work.

The pivotal evidence for Vyleesi comes from the RECONNECT phase 3 programme: two identically designed randomised, double-blind, placebo-controlled trials, BMT-301 and BMT-302, published in Obstetrics & Gynecology by Kingsberg and colleagues in 2019 (PMID 31599840). Premenopausal women with acquired, generalised HSDD self-administered 1.75 mg bremelanotide or placebo subcutaneously on an as-needed basis over a 24-week core period. The co-primary endpoints were change in the FSFI desire domain and change in the FSDS-DAO item 13 (a single-item distress measure). The trials reported statistically significant improvements on both endpoints versus placebo. The effect sizes are modest, not transformative, and the treated population reported high rates of nausea and other AEs covered in the Safety section. Simon and colleagues published a 52-week open-label safety extension (PMID 31599847) and a subsequent integrated subgroup analysis in 2022 (PMID 35230162).

Vyleesi was approved by the FDA on 21 June 2019 under NDA 210557, under the brand AMAG Pharmaceuticals held following its 2017 license from Palatin. AMAG sold the asset to Cosette Pharmaceuticals in 2021 after disappointing commercial sales, and Cosette has been the US marketing holder since then; the DailyMed label (last revised 10 January 2025) lists Cosette as the labeller alongside a Palatin label entry. In US practice today Vyleesi is supplied through the BlinkRx pharmacy platform, with most commercially-insured patients paying $0 for a 4-dose pack and uninsured patients paying $99 for a 4-dose pack. The dose, 1.75 mg subcutaneous self-injection in the abdomen or thigh at least 45 minutes before anticipated sexual activity, with a maximum of 8 doses per month and 1 dose per 24 hours, is the FDA label regimen.

Outside the United States the picture changes sharply. The EMA medicines register returns no marketing authorisation, EPAR or referral for bremelanotide. The MHRA in the UK has no marketing authorisation for Vyleesi either. There is no centrally-authorised product in the EU/EEA. Lawful access in the EU, EEA and UK therefore runs only through unlicensed-medicine or named-patient routes that a prescribing clinician requests and takes responsibility for, similar to tesamorelin (the other FDA-approved peptide in our library that lacks EU authorisation). General sale to the public is not lawful.

Off-label and grey-market use is where most online discussion of PT-141 sits, especially in men. Bremelanotide is widely sold by online 'research peptide' vendors as a libido and pre-activity enhancer for both sexes, dosed on schedules and at amounts that have not been studied in any controlled trial. The original intranasal programme tested male erectile dysfunction, but that programme was halted in 2007 on safety grounds, and the subcutaneous Vyleesi programme that succeeded it was confined to premenopausal women with HSDD. Male and postmenopausal use therefore sits outside both the approved indication and the controlled-trial evidence base. We report the grey-market reality honestly because readers will encounter it; we do not endorse the use pattern.

Bremelanotide is not explicitly named on the current WADA Prohibited List, but section S2 of that list captures peptide hormones, growth factors and related substances under broad categorical language, and section S0 captures non-approved substances generally. Athletes subject to the WADA Code should verify status through Global DRO or their national anti-doping authority before assuming clearance. This page is educational. We do not advise on starting, stopping, dosing or sourcing bremelanotide, and we do not facilitate the sale of any peptide. Decisions about whether to consider it, on label for HSDD or off label for any other reason, belong with a prescribing clinician who knows your medical history. Use the country pages at /regulation/[country]/pt141 for the jurisdiction-specific picture.