PT-141

What it is

PT-141 is the development code for bremelanotide, a synthetic melanocortin receptor agonist. In the United States, the approved prescription product is Vyleesi, a bremelanotide injection supplied as a single-dose autoinjector^{[2 ]}. The term “PT-141” is also used in gray-market peptide advertising, which can blur the distinction between an FDA-approved branded product and unapproved bulk powders, nasal sprays, or compounded products.

Chemical structure

PT-141 is bremelanotide, a cyclic seven-amino-acid melanocortin receptor agonist with sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH and molecular formula C50H68N14O10^{[1 ]}. It is related to Melanotan II but has a carboxylic acid terminus rather than the amide terminus of Melanotan II^{[1 ,8 ]}.

Mechanism

Bremelanotide activates melanocortin receptors. The exact mechanism by which melanocortin receptor agonism improves acquired, generalized hypoactive sexual desire disorder is unknown, but the FDA-approved label classifies it as a melanocortin receptor agonist^{[1 –2 ]}. The clinical effect is not equivalent to phosphodiesterase-5 inhibitors such as sildenafil, which act primarily through peripheral blood-flow pathways.

Approved indication

Vyleesi is approved only for a narrow population: premenopausal women with acquired, generalized HSDD not due to a coexisting medical or psychiatric condition, relationship problems, or the effects of a medication or drug^{[2 ]}. The label states that Vyleesi is not for HSDD in postmenopausal women or men, not for improving sexual performance, and not for use in children^{[2 ]}.

The product is administered by subcutaneous injection according to the FDA-approved labeling^{[2 ]}. This page describes the approved product and the research evidence; it does not provide dosing instructions or individualized guidance.

Regulatory status

Bremelanotide is FDA-approved as Vyleesi under a New Drug Application, with initial US approval in 2019^{[2 ]}. DailyMed lists Vyleesi as a human prescription drug with marketing status “New Drug Application” and DEA schedule “None”^{[2 ]}.

Approved indication boundaries

The FDA-approved indication is acquired, generalized hypoactive sexual desire disorder in premenopausal women as characterized in the label^{[2 ]}. The label specifically excludes use for HSDD due to coexisting medical or psychiatric conditions, relationship problems, or medication/drug effects, and states that Vyleesi is not for men, postmenopausal women, children, or sexual performance enhancement^{[2 ]}.

Compounding context

Compounding and gray-market PT-141 require careful distinction. FDA-approved Vyleesi has a reviewed formulation, device, labeling, manufacturing controls, adverse-event data, and risk information^{[2 ]}. Products marketed online as PT-141, research bremelanotide, or peptide libido injections are not automatically equivalent to Vyleesi. Under FDA’s compounding framework, compounded products must satisfy all applicable 503A or 503B conditions, including restrictions on essentially copying commercially available or approved drug products^{[5 –6 ]}.

Controlled-substance status

Bremelanotide was not identified in federal controlled-substance schedules in 21 CFR Part 1308 as reviewed for this draft^{[7 ]}. International availability varies by jurisdiction; this page focuses on the United States.

Date of last regulatory verification: May 5, 2026.

Research summary

RECONNECT phase 3 trials

The pivotal evidence for FDA approval came from the RECONNECT program. Kingsberg and colleagues reported two randomized, double-blind, placebo-controlled phase 3 trials in premenopausal women with hypoactive sexual desire disorder^{[3 ]}. In the trials, bremelanotide significantly improved sexual desire and reduced related distress compared with placebo, while nausea, flushing, and headache occurred more often with bremelanotide^{[3 ]}.

Long-term extension

The long-term extension study enrolled women who completed the 24-week double-blind core phase and had not experienced serious adverse events during that phase^{[4 ]}. The extension provided additional safety and persistence-of-effect information, but because it was open-label and selected for women who completed earlier treatment, it should not be interpreted the same way as a blinded randomized trial^{[4 ]}.

Label-defined safety boundaries

The FDA label emphasizes clinically relevant safety limitations. Vyleesi transiently increases blood pressure and reduces heart rate after each dose, and it is contraindicated in patients with uncontrolled hypertension or known cardiovascular disease^{[2 ]}. The label also warns about focal hyperpigmentation and nausea^{[2 ]}.

Distinguishing approved from unapproved use

Earlier melanocortin research included male erectile dysfunction and related sexual-function studies, but Vyleesi’s approved indication is not erectile dysfunction and is not use in men^{[2 ]}. Public and online peptide marketing sometimes generalizes PT-141 to men, couples, libido optimization, or performance; those claims are broader than the FDA-approved indication and should be separated from label-supported use.

Overall, bremelanotide has approval-quality evidence for one specific HSDD indication and FDA-reviewed safety information for the approved product^{[2 –4 ]}. The evidence should not be generalized to nonapproved populations, gray-market products, nasal sprays, compounded copies, or sexual-performance enhancement.

Public discourse

Hylton Joffe, MD, FDA CDER reproductive and urologic products official, framed the approval as addressing a subset of women with distressing reduced desire^{[9 –10 ]}.

The DailyMed/FDA-approved patient labeling for Vyleesi emphasizes boundaries of use^{[2 ]}.

Public discourse reflects the views of the speakers cited and does not represent medical advice or the editorial position of ProPeptideGuide.

Side effects and safety

The FDA-approved label contraindicates Vyleesi in patients with uncontrolled hypertension or known cardiovascular disease^{[2 ]}. The label warns that bremelanotide transiently increases blood pressure and reduces heart rate after dosing, usually resolving within 12 hours^{[2 ]}.

Nausea

Nausea is the most common adverse reaction. In phase 3 placebo-controlled trials, nausea occurred in 40% of Vyleesi-treated patients, required antiemetic therapy in 13%, and led to premature discontinuation for 8%^{[2 ]}. Other common adverse reactions include flushing, injection-site reactions, headache, vomiting, hot flush, nasal congestion, cough, tingling, fatigue, and dizziness^{[2 ]}.

Focal hyperpigmentation

Focal hyperpigmentation is another label warning. In phase 3 trials, focal hyperpigmentation involving areas such as face, gingiva, and breasts was reported in 1% of treated patients and no placebo patients; higher-frequency daily exposure in another study produced substantially more pigmentation changes^{[2 ]}. Resolution was not confirmed in all patients after discontinuation^{[2 ]}.

Drug interactions and special populations

The label notes that Vyleesi may slow gastric emptying and reduce the rate and extent of absorption of some orally administered medications, including naltrexone^{[2 ]}. Severe renal impairment and severe hepatic impairment may increase adverse-reaction risk^{[2 ]}.

Safety data apply to FDA-approved Vyleesi, not to gray-market PT-141 powders, nasal sprays, or unverified compounded products. Nonapproved products raise separate concerns about identity, sterility, concentration, impurities, and labeling.

Available through

FDA-approved bremelanotide is available in the United States by prescription as Vyleesi through licensed prescribing and pharmacy channels, when used within the approved product framework^{[2 ]}.

Provider-platform listings will be added only after legal and editorial verification that the platform prescribes FDA-approved Vyleesi through licensed clinicians and dispenses through compliant pharmacy channels. ProPeptideGuide does not link to or endorse gray-market PT-141 vendors, research-chemical sellers, nasal sprays, or unverified compounded products.