PT-141 (Bremelanotide)
Melanocortin receptor agonist
A melanocortin-receptor agonist studied in neuropeptide research.
Also referenced as: Bremelanotide
Overview
PT-141 (bremelanotide) is a synthetic cyclic heptapeptide melanocortin agonist derived from the melanocortin peptide Melanotan II. It is marketed as Vyleesi.
At a glance
What PT-141 (Bremelanotide) does
PT-141 (bremelanotide) is unusual among these compounds because it does not act on the HPG axis or on the gonads at all — it works centrally in the brain on the melanocortin system. It is a cyclic melanocortin-receptor agonist derived from Melanotan II, and its sexual effects are attributed mainly to activation of the melanocortin-4 receptor (MC4R), with additional activity at MC3R and other melanocortin subtypes. Rather than acting on blood flow or hormones peripherally, it modulates central pathways involved in sexual arousal and desire, which is why its effect is on wanting/arousal rather than on erectile hemodynamics per se.
Bremelanotide is notable for being an FDA-approved drug: as Vyleesi, it is approved for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD), given by subcutaneous injection on an as-needed basis before anticipated sexual activity. In placebo-controlled trials of roughly 1,200 women it produced modest but statistically significant improvements in sexual-desire scores and reduced associated distress compared with placebo. Functional-MRI work has been used to probe how it alters activity in brain regions linked to sexual response. Notably, the FDA label states that the precise mechanism by which it improves desire remains not fully understood.
Because it is a broad melanocortin agonist, its actions extend beyond sexual behavior: melanocortin receptors are widely expressed, which underlies its characteristic side effects. Its central, MC4R-mediated pro-sexual action is supported by both human clinical trials and animal models.
Effects reported in research
- Activates central melanocortin receptors, principally MC4R (with MC3R and other subtypes), rather than acting on hormones or peripheral blood flow (human and animal).
- Increases sexual desire/arousal centrally; FDA-approved as Vyleesi for premenopausal women with acquired, generalized HSDD (human clinical, regulatory).
- Produced modest but statistically significant improvements in desire scores versus placebo in trials of ~1,200 women (human RCTs).
- Reduced sexual-desire-related distress compared with placebo in HSDD trials (human RCTs).
- Altered activity in brain regions associated with sexual response on functional-MRI studies (human imaging).
- Studied for erectile response in men, acting via central arousal pathways rather than direct vascular action (human and animal studies).
- Frequently causes nausea (about 40% of trial participants), often with the first dose (human trial data).
- Can darken gums and skin in a minority of users, reflecting broad melanocortin-receptor (including MC1R) activation (human trial data).
Effects listed reflect findings reported in the research literature — many in animal or in-vitro models. Listing an effect is not a claim of efficacy or a therapeutic indication in humans.
Mechanism of action
PT-141 (bremelanotide) is a melanocortin receptor agonist with activity at MC4R (and other melanocortin receptors) in the central nervous system. Activation of MC4R in hypothalamic pathways is associated with modulation of sexual-response signaling, which is the mechanistic basis for its study and approved indication in sexual dysfunction. Unlike vasodilator-based therapies, it acts on central melanocortin pathways rather than peripheral vascular targets.
Mechanistic description reflects published research-literature understanding. Much peptide research is preclinical (in-vitro or animal-model); mechanism in humans may differ and is not established for many compounds.
What it's studied for
Research contexts in which PT-141 (Bremelanotide) appears in the literature. Listing a research area is not a claim of efficacy or a therapeutic indication.
Key characteristics
- Bremelanotide, a cyclic heptapeptide melanocortin agonist.
- Derived structurally from Melanotan II but developed as a distinct drug.
- Acts centrally via MC4R rather than peripheral vasodilation.
- FDA-approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women.
- Mechanistically related to Melanotan II through shared MC4R agonism.
Reported research dosing reference only
Educational reference, not dosing guidance. The figures below summarize amounts reported in published research and research-community protocols, provided for educational and research context only. They are not medical advice, not a recommendation, and not instructions for human use. PT-141 (Bremelanotide) is a research compound.
Reference figures only. The FDA-approved Vyleesi label specifies 1.75 mg subcutaneously as-needed; research-literature figures generally track this approved dose.
- Approved label (Vyleesi): 1.75 mg subcutaneous, as-needed at least 45 min before activity
- Research literature: single subcutaneous doses commonly referenced around 1-2 mg
MC4R agonism can raise blood pressure and cause nausea/flushing in studies; ~2.5 h half-life. Reference figures for research context only, not dosing guidance.
How it compares
PT-141 is an MC4R-focused, centrally acting approved drug (Vyleesi), distinguishing it from the non-selective tanning-oriented Melanotan II and from peripheral vasoactive agents.
Handling & Stability
Lyophilized peptides are stored cold, protected from light, and reconstituted only at the time of intended in-vitro work.
- Avoid repeated freeze-thaw cycles
- Verify supplier lot and Certificate of Analysis
- Follow institutional lab-safety protocols
Analytical & COA Concepts
Reputable research suppliers publish a third-party Certificate of Analysis per batch. Key analytical concepts referenced in COAs include:
Category Context
PT-141 (Bremelanotide) sits in the Hormonal & Sexual Health area of the PeptiDex library.
- Entry type: Research compound reference
- Browse the full library →
- Glossary of terms →
Where researchers source PT-141 (Bremelanotide)
For researchers studying PT-141 (Bremelanotide), third-party suppliers such as Practically Natty Peptides offer research-grade material with third-party Certificates of Analysis and US-based shipping.
View research-supplier listing →
Outbound link to a third-party research supplier. Inclusion does not constitute endorsement; all editorial content is developed independently.
Frequently asked questions
What is PT-141 (bremelanotide)?
PT-141 (bremelanotide) is a synthetic cyclic 7-amino-acid melanocortin receptor agonist, a metabolite-derived analog of alpha-MSH. It preferentially activates the melanocortin-4 receptor (MC4R) in the central nervous system and is studied in the context of sexual arousal and desire pathways rather than acting on the vasculature.
Is PT-141 an FDA-approved drug?
Yes. Bremelanotide is FDA-approved (June 2019) under the brand name Vyleesi for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women. It was the first approved as-needed injectable for HSDD. Research-chemical supply of the same molecule is a separate, non-pharmaceutical channel and is not the approved product.
How does PT-141 differ from PDE5 inhibitors like sildenafil?
PT-141 works centrally through MC4R activation in the hypothalamus to influence desire and arousal, whereas PDE5 inhibitors act peripherally on smooth-muscle blood flow. This is a fundamentally different mechanism, which is why it is studied in desire-focused rather than purely erectile models.
What is PT-141's half-life and how is it dosed in the label?
After subcutaneous administration its half-life is about 2.5 hours, reaching peak plasma concentration around 1 hour with essentially complete bioavailability. The approved Vyleesi label is 1.75 mg subcutaneously as-needed at least 45 minutes before anticipated activity, no more than one dose per 24 hours and no more than 8 per month.
How is PT-141 eliminated?
Bremelanotide is cleared primarily by renal excretion (approximately 65%), with a smaller fecal component (approximately 23%), and is metabolized through hydrolysis of the peptide. This renal-dominant clearance is relevant when interpreting pharmacokinetic research.
Answers are educational summaries of research-literature context and do not constitute medical advice. See the Research Library, COA guide, and Storage & Handling guide for more.