Gathering the record
Relay is organizing the evidence and source boundaries.
Nonselective melanocortin-receptor agonist cyclic heptapeptide
PT-141 is the development name for bremelanotide. VYLEESI is an FDA-approved, ready-to-use bremelanotide autoinjector for a narrow form of distressing low sexual desire in certain premenopausal women. That approval does not establish a general libido, sexual-performance, male erectile-dysfunction, weight-loss, or kidney-disease treatment.
60-Second Overview
Start with what it is, why it matters, what research has shown, and what remains unknown. The science follows after the orientation.
Start here. These four answers explain why the compound matters before the page introduces the deeper science.
PT-141 is the development name for bremelanotide. VYLEESI is a specific ready-to-use bremelanotide product approved for a narrow form of distressing low sexual desire in certain premenopausal women.
Unlike medicines that act mainly through blood flow, bremelanotide influences melanocortin signals in the nervous system. Researchers have studied sexual desire, erectile response, and several preliminary metabolic or kidney questions.
Two large Phase 3 trials found improvements in sexual-desire and distress scores in the approved population, but not in the number of satisfying sexual events. Older male research is limited, and preliminary obesity and kidney signals remain unconfirmed.
Durability, rare harms, generalizability outside the labeled population, and newer metabolic or kidney outcomes remain unresolved. The approved autoinjector instructions do not establish a general PT-141 reconstitution process.
The research depth, routes, studies, and primary sources below explain how Relay knows—and where the evidence stops.
Research context
Published research has investigated this compound using the following study designs.
These records explain what researchers did. They are not instructions, recommendations, or a transferable protocol.
Two pivotal controlled trials evaluated a ready-to-use bremelanotide product in premenopausal women with acquired, generalized hypoactive sexual desire disorder.
Reported study administration—not a recommendation.
Research at a glance
Evidence depth, confidence, and route context explain how Relay knows—not what anyone should do.
Bremelanotide has dose-ranging, pivotal Phase 3, long-term extension, mechanistic, and investigational human studies plus an approved SubQ product.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Two large controlled trials support desire and distress outcomes in defined premenopausal HSDD, while male, obesity, kidney, and broad performance claims remain unapproved or preliminary.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The evidence applies to a narrow diagnosed population and relied on patient-reported outcomes with substantial attrition. It does not establish a male indication, general sexual-performance benefit, or reconstitution instructions for other products. Amounts shown describe cited research exposure—not a dosage recommendation.
Detailed evidence
Start with the strongest supported conclusion and its main uncertainty. Claim-level records below show how the evidence changes by question, population, route, formulation, and study design.
Two randomized Phase 3 trials involving 1,267 premenopausal women with acquired, generalized HSDD, supported by a current FDA label and earlier dose-ranging research.
This is the strongest supported conclusion in the current human evidence—not a summary of every claim made about the compound.
Durability and rare safety with real-world use, generalizability outside the labeled population, and whether preliminary obesity or kidney signals survive full peer review and larger controlled trials.
Keeping the main uncertainty visible prevents an early or promising finding from looking more settled than it is.
Questions people bring to the evidence
Research questions—not promises of benefit.
PT-141 is the development name commonly used for bremelanotide. VYLEESI is a sterile, ready-to-use bremelanotide-acetate autoinjector with a defined prescription label.
The label lists potency in the order MC1R, MC4R, MC3R, MC5R, and MC2R. MC4R-expressing neurons are present in the central nervous system, while MC1R activation explains pigmentation effects.
The approved population has low desire that causes marked distress or interpersonal difficulty and is not explained by a medical or psychiatric condition, relationship problem, or medication or drug.
Across the two RECONNECT trials, bremelanotide improved the co-primary desire and distress measures versus placebo. The number of satisfying sexual events did not differ significantly.
In pooled Phase 3 labeling, nausea occurred in 40%, flushing in 20.3%, injection-site reactions in 13.2%, headache in 11.3%, and vomiting in 4.8%. Each dose can transiently increase blood pressure and reduce heart rate.
Older intranasal studies reported erectile-response signals, but VYLEESI is not indicated for men. The largest sildenafil-nonresponder paper also carries a journal Expression of Concern.
BMT-801 compared bremelanotide, tirzepatide, their combination, and placebo over a short period. The sponsor reported greater weight reduction in the combination group.
BREAKOUT reported proteinuria and filtration-rate signals, but only eight of 16 enrolled participants completed six months and there was no comparator group.
The label warns about oral drugs that depend on threshold concentrations or rapid onset and says to avoid oral naltrexone products used for alcohol or opioid addiction.
VYLEESI is a sterile, clear, ready-to-use 1.75 mg/0.3 mL solution in a single-dose autoinjector. Its label specifies product handling and does not describe reconstituting a powder.
Mechanisms
Bremelanotide is a synthetic cyclic heptapeptide that nonselectively activates melanocortin receptors. At labeled exposure, MC1R and MC4R are most relevant; the exact HSDD mechanism remains unknown. Two large randomized Phase 3 studies demonstrated statistically significant improvements in desire and distress scores, but not satisfying sexual events. The safety profile includes frequent nausea, transient blood-pressure and heart-rate effects, focal hyperpigmentation, and oral-drug absorption considerations. Newer obesity and diabetic-kidney programs remain preliminary and sponsor reported.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Randomized, double-blind, placebo-controlled, two-way crossover study with functional neuroimaging
Premenopausal heterosexual women with hypoactive sexual desire disorder
Bremelanotide increased self-reported sexual desire for up to 24 hours and changed activation in brain regions involved in sexual processing.
Study administration: Single subcutaneous bremelanotide dose and placebo in crossover sequence
Limitations: Small mechanistic study with a single dose and specialized imaging outcomes. It does not establish broad sexual-performance effects or outcomes in men, postmenopausal women, or people without diagnosed HSDD.
Two identical randomized, double-blind, placebo-controlled, multicenter trials
Premenopausal women with acquired, generalized hypoactive sexual desire disorder
Bremelanotide improved sexual-desire scores and reduced distress related to low desire versus placebo. It did not significantly improve the number of satisfying sexual events.
Study administration: As-needed subcutaneous bremelanotide 1.75 mg or placebo under the study protocol
Limitations: The evidence applies to the narrow diagnosed premenopausal HSDD population and the studied ready-to-use subcutaneous product. Attrition was substantial, outcomes were patient-reported, and sponsor employees or contractors were involved.
Randomized, double-blind, placebo-controlled dose-finding trial
Premenopausal women with hypoactive sexual desire disorder, female sexual arousal disorder, or both
The pooled 1.25 mg and 1.75 mg groups improved satisfying sexual events, overall sexual-function score, and sexual-distress score more than placebo.
Study administration: As-needed subcutaneous placebo or bremelanotide 0.75 mg, 1.25 mg, or 1.75 mg under the trial protocol
Limitations: The primary efficacy analysis pooled two doses and included 327 participants. Diagnostic categories and endpoints differ from the final approved indication and pivotal Phase 3 endpoint strategy.
Randomized, double-blind, placebo-controlled study reported in 2008
Men with erectile dysfunction reported as nonresponsive to sildenafil
The paper reported improved erectile-function outcomes with intranasal bremelanotide.
Study administration: Intranasal bremelanotide or placebo under the study protocol
Limitations: The journal issued an Expression of Concern in 2023. The study used an intranasal regimen, has not supported an FDA-approved indication in men, and should not be treated as reliable proof for current products or routes.
Uncontrolled 52-week extension after the 24-week core trials
Core-trial completers without a serious adverse event that precluded extension participation
Symptom improvements were maintained during the extension, and the safety pattern was generally consistent with the core studies.
Study administration: As-needed subcutaneous bremelanotide under the extension protocol
Limitations: There was no concurrent placebo group, extension entry selected core completers without disqualifying serious adverse events, and loss to follow-up can bias long-term estimates.
Randomized, double-blind, placebo-controlled, four-arm study after a tirzepatide lead-in
Adults with obesity
The sponsor reported 4.4% weight reduction in the co-administered group versus 1.6% with placebo over the eight-week total period, with more participants reaching selected weight-loss thresholds.
Study administration: Bremelanotide plus tirzepatide, tirzepatide alone, bremelanotide alone, or placebo under the registered protocol
Limitations: Short, small, imbalanced study with sponsor-reported topline results only. A full peer-reviewed report was not located, and the data do not establish an approved obesity indication or proven synergy.
Prospective, multicenter, open-label, uncontrolled study
Adults with type 2 diabetic nephropathy and urine protein-to-creatinine ratio above 1,000 mg/g
The sponsor reported that 71% of analyzed participants achieved a greater than 30% reduction in urine protein-to-creatinine ratio and 71% had improved or stable estimated filtration rate.
Study administration: Subcutaneous bremelanotide twice daily plus maximum tolerated renin-angiotensin-aldosterone-system inhibition under the study protocol
Limitations: Only eight of 16 enrolled participants completed six months, there was no control group, and results were sponsor topline rather than a located full peer-reviewed report. Hyperpigmentation was reported in 71%.
Safety snapshot
Nausea, flushing, injection-site reactions, headache, vomiting, blood-pressure effects, and hyperpigmentation are important known safety findings.
Controlled human evidenceTrial rates may not predict an individual experience. The product is contraindicated in uncontrolled hypertension or known cardiovascular disease, and pigmentation may not resolve in every patient.
Open sourceThe current record does not support a reliable common-versus-uncommon frequency split.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
No source-qualified compound-specific warning or contraindication is encoded in the current record.
Evidence boundaryFDA approved as VYLEESI only for acquired, generalized HSDD in certain premenopausal women. It is not indicated for postmenopausal women, men, sexual-performance enhancement, obesity, or kidney disease. Durability and rare safety with real-world use, generalizability outside the labeled population, and whether preliminary obesity or kidney signals survive full peer review and larger controlled trials.
The current record does not identify a reliable compound-specific pattern of events that caused study discontinuation.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
No compound-specific patient-facing urgent-action threshold is established in the current Relay record.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
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