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PT-141 (Bremelanotide)

Also known as: Bremelanotide, Vyleesi, PT-141 Acetate

FDA Approved

Molecular Formula

C50 H68 N14 O10 Fr Ba

Molecular Weight

1,025.2 Da (Free Base; Bremelanotide Acetate salt)

Half-Life

2.7 hours (range 1.9–4.0 hours for 1.75 mg SC Vyleesi dose)

Sequence

Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH

Clinical Applications & Evidence

Mechanism of Action

Bremelanotide binds nonselectively to melanocortin receptors with potency order MC1R > MC4R > MC3R > MC5R > MC2R. Central MC4R activation in hypothalamic pathways is implicated in sexual desire in preclinical models; however, FDA labeling states that the precise mechanism by which Vyleesi improves HSDD in humans is unknown. MC1R activation stimulates melanogenesis, accounting for the risk of focal hyperpigmentation.

Investigated Uses

  • Acquired, generalized HSDD in premenopausal women (FDA-Approved indication — Vyleesi 1.75 mg SC)
  • Erectile dysfunction in men (Investigational — historical intranasal & SC pilot studies; not FDA-approved for male use)
  • Female sexual arousal disorders (Investigational — off-label research outside premenopausal HSDD approval)
Extensive Clinical Data

Regulatory & Safety Status

FDA Status

FDA Approved

WADA / Athletic Status

Not Explicitly Prohibited

Known Side Effects

Nausea (40.0% of Phase 3 trial participants; 13% required antiemetics; 8% discontinued due to nausea)Flushing (20.3%) and injection site reactions (13.2%)Headache (11.3%) and vomiting (4.8%)Transient blood pressure elevation (average +6 mmHg systolic 2–4 hours post-dose) and pulse reductionFocal hyperpigmentation (~1% with intermittent use; affects face, gums, breasts; may be persistent)

Contraindications

  • Uncontrolled hypertension or known cardiovascular disease (Contraindicated due to transient BP spikes)
  • Pregnancy and lactation (Not recommended; effective contraception advised during treatment)
  • Patients at high risk for cardiovascular events

Drug Interactions

  • Oral Naltrexone (Bremelanotide significantly reduces naltrexone exposure, risking alcohol/opioid addiction treatment failure)
  • Concomitant oral medications requiring rapid gastrointestinal absorption (Bremelanotide delays gastric emptying, delaying onset of oral analgesics like Indomethacin or oral antibiotics)

Citations & Clinical Trials

PubMed Bremelanotide for Hypoactive Sexual Desire Disorder: RECONNECT Phase 3 Trials (2019) Europe PMC Long-Term Safety and Efficacy of Bremelanotide for HSDD (2019) PubMed Evaluation of Intranasal Bremelanotide in Men with ED (2008) DailyMed / NIH DailyMed Prescribing Information: Vyleesi (Bremelanotide Subcutaneous Injection) World Anti-Doping Agency WADA 2026 Prohibited List — Anti-Doping Guidance