PT-141 (Bremelanotide): What the Published Research Shows

Bremelanotide (PT-141) is a synthetic cyclic heptapeptide and a melanocortin receptor (MCR) agonist. It is also known by the trade name Vyleesi and is formulated as bremelanotide acetate. The published literature characterises it as a macrocyclic peptide whose ring size places it in a chemical class that balances the properties of small molecules and biologics, with optimisation of affinity, stability, and pharmacokinetics [1]. Bremelanotide is a metabolite-derived analogue of the peptide melanotan II; the wider class of melanocortin peptides includes setmelanotide, and both are cited in the recent literature as examples of macrocyclic peptides that have achieved clinical success [1]. The evidence block supplied for this page does not give a sequence, molecular formula, or molecular weight for bremelanotide, so none are stated here.

The work on this compound centres on the melanocortin receptor family, and in particular on MC4R, which is the receptor subtype most directly implicated in the central pathways the research literature associates with sexual desire and arousal [8]. Bremelanotide is described in the trial literature as a melanocortin receptor agonist [6].

Research Studies

Bremelanotide and melanocortin receptor selectivity in human receptor assays

A medicinal-chemistry programme designed and synthesised a series of 14 macrocyclic peptide analogues with 19- to 23-membered rings, built on the MT-II, SHU-9119, and PG-901 scaffolds, and assessed their pharmacological activity against human MC1R, MC3R, MC4R, and MC5R [1]. The paper frames bremelanotide and setmelanotide as evidence that macrocyclic peptides can achieve clinical success, while noting that selective MCR targeting with an optimal pharmacological profile remains difficult to achieve [1]. This is in vitro pharmacology against cloned human receptors, not an in vivo model.

Bremelanotide and MC4R activation in premenopausal women with HSDD

A randomised, double-blind, placebo-controlled, two-way crossover physiological study was designed to evaluate the effects of MC4R activation on brain activity patterns and on behavioural psychometric measures of sexual arousal during visual erotic stimuli [8]. The population was approximately 40 right-handed, heterosexual, premenopausal women aged 18 years and over with hypoactive sexual desire disorder (HSDD) of at least six months' duration [8]. This study addresses the receptor mechanism directly rather than a clinical endpoint.

Bremelanotide and HSDD in premenopausal women: a Phase 3 bridging trial

A Phase 3, bridging, multicentre, randomised, double-blind, placebo-controlled, parallel-group trial was set up to evaluate the efficacy and safety of subcutaneously administered bremelanotide in premenopausal women with HSDD, with or without decreased arousal [7]. The stated purpose of the study is the evaluation of efficacy and safety in that population [7].

Bremelanotide and HSDD in the registered clinical trial landscape

A systematic review conducted in accordance with PRISMA 2020 examined registered clinical trials of emerging pharmacological therapies for HSDD in women, on the basis that pharmacological options remain limited and that evidence from individual trials is heterogeneous [2]. The review's rationale is that a systematic evaluation of registered trials is needed to understand therapeutic development, efficacy endpoints, and safety profiles of emerging treatments [2]. Bremelanotide is one of the agents within that therapeutic area.

Bremelanotide and breast milk pharmacokinetics in lactating women

An open-label pharmacokinetic study was designed to evaluate whether bremelanotide is secreted in breast milk in lactating women given a single 1.75 mg subcutaneous dose, and to measure the concentration and characterise the pharmacokinetics of the drug in breast milk [4]. The study population is 10 healthy lactating female subjects between 10 days and 6 months post-partum inclusive, with a maximum participation duration of approximately 29 days comprising a 3-week screening period and a 1-day treatment period [4].

Bremelanotide and obesity: co-administration with tirzepatide

A prospective, randomised, double-blind, placebo-controlled Phase 2 study was designed to assess the safety and efficacy of bremelanotide used in combination with tirzepatide therapy in the treatment of obesity, in subjects with a BMI from 30.0 to 45.0 kg/m2 inclusive [5]. The design is a combination-therapy study rather than a monotherapy study [5].

Bremelanotide and diabetic kidney disease

A Phase IIb, multicentre, open-label, prospective study was designed to assess the efficacy of the melanocortin receptor agonist bremelanotide when administered with RAAS inhibition therapy after six months in subjects with Type II diabetic nephropathy [6]. After six months of therapy, all subjects were to remain in the trial for further assessment and to undergo a diagnostic renal biopsy to assess the effect of melanocortin therapy on diabetic histopathology at 12 months [6].

Bremelanotide and peptide therapeutics in ageing research

A narrative review of therapeutic peptides in gerontology examined mechanisms, clinical applications, evidence base, and safety profiles of peptides with demonstrated or potential applications in healthy ageing and age-related conditions, targeting hallmarks of ageing that include metabolic dysfunction, telomere attrition, tissue repair impairment, and hormonal decline [3]. The review's searches covered PubMed, Scopus, and the FDA and WADA regulatory databases from inception through January 2026 [3]. Bremelanotide sits within the broader peptide-therapeutics field that this review surveys; the review is not a bremelanotide-specific study.

Bremelanotide and analytical characterisation of the acetate salt

A stability-indicating RP-HPLC method was developed for bremelanotide, with degradation products characterised by LC-HRMS/MS combined with computational approaches, in work aimed at characterising bremelanotide acetate and its degradants and at predicting epimerisation through computational modelling [9]. The paper's premise is that the intrinsic stability and degradation behaviour of this cyclic peptide therapeutic had not been extensively investigated [9]. This is analytical and computational chemistry, not a pharmacological or clinical study.

Bremelanotide and the wider context of peptide drug design

A historical and developmental review of FDA-approved drugs containing D-amino acids describes D-amino acids as non-natural enantiomers of L-amino acids that have become useful in peptide drug development because of resistance to proteolytic degradation, enhanced conformational rigidity, and reduced immunogenicity [11]. That review is a general account of the class and is not a bremelanotide study; it is relevant here only as background to why peptides of this kind are designed as they are.

Bremelanotide and the HSDD trial literature

A paper on the quantification of what it terms "mercy sex" in heterosexual women notes that clinical trials of testosterone therapy, flibanserin, and bremelanotide in HSDD span nearly a decade, and that women with HSDD in those trials form a defined population [10]. The paper is a behavioural analysis rather than a pharmacological evaluation of bremelanotide, and it is included here only as an indication of how the HSDD trial literature has been used in secondary analysis [10].

Bremelanotide in men: an open question in the literature

A paper in the literature asks whether bremelanotide should be considered for the treatment of sexual arousal and desire disorders in men [12]. The evidence block supplied for this page does not include the findings of that paper, so no result is reported here; the item is noted only to indicate that the question has been raised in the published literature [12].

If you are reading this for personal health reasons

The material described on this page is sold for laboratory research use only, and we do not provide dosing information or medical guidance of any kind. Nothing here is a recommendation to use bremelanotide or any other compound. Anyone considering a compound for themselves should speak to a licensed clinician.

Sources

• [1] Goldilocks-Inspired Design of Mid-Size Macrocycles for Selective Targeting of Human Melanocortin Receptors — https://europepmc.org/article/PMC/PMC13492293
• [2] Clinical trial evidence on emerging pharmacological therapies for hypoactive sexual desire disorder in women: a systematic review and analysis of completed studies registered on ClinicalTrials.gov — https://europepmc.org/article/PMC/PMC13237691
• [3] Therapeutic peptides in gerontology: mechanisms and applications for healthy aging — https://europepmc.org/article/PMC/PMC13095733
• [4] Single Dose of Vyleesi in Lactating Female Subjects to Measure the Concentration of Bremelanotide in Breast Milk — https://clinicaltrials.gov/study/NCT06867835
• [5] A Phase 2 Study Evaluating the Co-Administration of Bremelanotide With Tirzepatide for the Treatment of Obesity — https://clinicaltrials.gov/study/NCT06565611
• [6] A Phase IIb, Multicenter, Open-Label, Prospective Study of Bremelanotide in Diabetic Kidney Disease — https://clinicaltrials.gov/study/NCT05709444
• [7] A Phase 3, Bridging, Multicenter, Randomized, Double-blind, Placebo-controlled, Parallel-group Trial to Evaluate the Efficacy and Safety of Subcutaneously Administered Bremelanotide in Premenopausal Women With Hypoactive Sexual Desire Disorder (With or Without Decreased Arousal) — https://clinicaltrials.gov/study/NCT04943068
• [8] Role of the Melanocortin-4 Receptor in Hypoactive Sexual Desire Disorder — https://clinicaltrials.gov/study/NCT04179734
• [9] Comprehensive characterization of bremelanotide acetate and its degradants by LC-HRMS/MS and predicting epimerization through computational modelling — https://pubmed.ncbi.nlm.nih.gov/42485063/
• [10] Quantification of "Mercy Sex" in Heterosexual Women — https://pubmed.ncbi.nlm.nih.gov/42144994/
• [11] FDA-Approved Drugs Containing D-Amino Acids: A Historical and Developmental Perspective — https://pubmed.ncbi.nlm.nih.gov/42041173/
• [12] Should Bremelanotide Be Considered for the Treatment of Sexual Arousal and Desire Disorders in Men? — https://pubmed.ncbi.nlm.nih.gov/41960633/