PT-141, also known by its chemical name bremelanotide, is a synthetic cyclic heptapeptide that has attracted significant scientific interest for its interactions with melanocortin receptors — particularly MC3R and MC4R — within the central nervous system. Unlike many peptides studied in metabolic or tissue-repair contexts, PT-141 research has focused predominantly on CNS-mediated signaling pathways that intersect with arousal, motivation, and autonomic regulation. As a research peptide, PT-141 represents a structurally distinct compound derived from the melanocyte-stimulating hormone (MSH) family, making it a compelling subject for receptor pharmacology investigations.
Researchers exploring the melanocortin system have found PT-141 to be a particularly useful tool compound due to its receptor selectivity profile and its ability to cross the blood-brain barrier — a property that distinguishes it from many peripherally acting peptides. Preclinical models and early translational studies have examined how MC3R and MC4R agonism influences a range of physiological and behavioral endpoints, positioning PT-141 as a well-characterized probe for central melanocortin pathway research.
Research-only notice: This content is provided for educational discussion and laboratory research purposes only. No medical claims are made or implied. PT-141 is intended exclusively for in vitro and preclinical research use. It is not approved for human consumption in a research context.
PT-141 - 10MG — Research-Grade Reference Material PT-141 - 10MG is supplied as a lyophilized powder for in-vitro laboratory research use only. SourcePeptides supplies this material strictly as a laboratory reference standard.…
View Research Data
Pfizer Hospira Bacteriostatic Water – 30 mL
$45.00$33.75 with 1st order
Ipamorelin - 10MG
$55.00$41.25 with 1st order
BPC-157 - 10MG / TB-500 - 10MG (Wolverine 20MG)
$110.00$82.50 with 1st order
Lipo-C 10ML
$115.00$86.25 with 1st order
Frequently Asked Questions
What is PT-141 (Bremelanotide)?
PT-141, also called bremelanotide, is a synthetic cyclic heptapeptide analog of alpha-MSH (melanocyte-stimulating hormone). Research has investigated its role as a melanocortin receptor agonist, particularly at MC3R and MC4R subtypes in the central nervous system. It was originally derived from Melanotan II and has been studied in preclinical models exploring autonomic and CNS-mediated signaling pathways.
What receptors does PT-141 target?
PT-141 primarily targets melanocortin receptors, with documented affinity for MC1R, MC3R, MC4R, and MC5R. Research literature most extensively examines its activity at MC3R and MC4R, both of which are expressed in brain regions associated with motivation, reward, and autonomic regulation. The selectivity profile makes it a useful tool compound for central melanocortin pathway studies.
How does PT-141 differ from Melanotan II in research?
PT-141 is a cyclic metabolite derived from Melanotan II (MT-II). While both compounds interact with melanocortin receptors, PT-141 has a distinct structural conformation that results in a different receptor selectivity and pharmacokinetic profile. Unlike MT-II, PT-141 lacks an acetyl group and has been more extensively characterized in formal preclinical and translational research contexts.
Can PT-141 cross the blood-brain barrier?
Preclinical research suggests that PT-141 is capable of crossing the blood-brain barrier, which is considered a key characteristic enabling its CNS-mediated effects in animal models. This property distinguishes PT-141 from many peripherally acting peptides and is one reason it has been studied as a probe for central melanocortin receptor pharmacology.
What has PT-141 research been used to study?
In preclinical models, PT-141 research has explored central melanocortin signaling, autonomic nervous system modulation, and behavioral endpoints related to reward and arousal pathways. Researchers have also investigated its interactions with dopaminergic signaling and its potential as a pharmacological tool for understanding hypothalamic circuit function.
Is PT-141 the same as Vyleesi?
Bremelanotide (the active molecule in PT-141) is the same compound as the active ingredient in Vyleesi, which received FDA approval in 2019 for a specific indication in premenopausal women. In a research context, PT-141 refers to the peptide compound used as a laboratory tool for studying melanocortin receptor biology, separate from any clinical application.
What is the molecular structure of PT-141?
PT-141 is a cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. It has a molecular weight of approximately 1025.2 Da and a molecular formula of C₅₀H₆₈N₁₄O₁₀. Its cyclic structure contributes to improved metabolic stability compared to linear peptide analogs in research settings.
Where can researchers source PT-141 for laboratory use?
Researchers can obtain PT-141 from specialized peptide suppliers who provide certificates of analysis and third-party purity verification. For laboratory research purposes, it is available in lyophilized powder form or as a nasal spray formulation from qualified peptide research suppliers.
Molecular Structure & Pharmacological Profile
Understanding PT-141’s pharmacological activity begins with its molecular architecture. As a cyclic heptapeptide analog, PT-141 was engineered to improve upon the stability and receptor binding characteristics of linear MSH analogs. Its cyclic backbone — formed by a lactam bridge — confers resistance to enzymatic degradation, a property that has made it a practical tool compound in in vivo preclinical research where peptide half-life is a meaningful experimental variable.
PT-141 - 10MG — Research-Grade Reference Material PT-141 - 10MG is supplied as a lyophilized powder for in-vitro laboratory research use only. SourcePeptides supplies this material strictly as a laboratory reference standard.…
View Research Data
Pfizer Hospira Bacteriostatic Water – 30 mL
$45.00$33.75 with 1st order
Ipamorelin - 10MG
$55.00$41.25 with 1st order
BPC-157 - 10MG / TB-500 - 10MG (Wolverine 20MG)
$110.00$82.50 with 1st order
Lipo-C 10ML
$115.00$86.25 with 1st order
PT-141 carries the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, with D-Phe substitution at position 7 of the parent alpha-MSH sequence contributing to enhanced receptor affinity. Research has characterized its binding kinetics at multiple melanocortin receptor subtypes, with Ki values reported across MC1R, MC3R, MC4R, and MC5R. The compound’s documented ability to penetrate the blood-brain barrier has made it especially relevant in central receptor pharmacology research, setting it apart from peptides that exert primarily peripheral effects.
Melanocortin Receptor Subtype Selectivity
The melanocortin receptor family comprises five G protein-coupled receptor subtypes (MC1R through MC5R), each with distinct tissue expression patterns and downstream signaling characteristics. PT-141 research has demonstrated meaningful affinity at MC3R and MC4R in particular — two subtypes with substantial expression in the hypothalamus and limbic system. MC4R activation in the paraventricular nucleus and other hypothalamic regions has been associated with autonomic and behavioral outputs that researchers have sought to map using PT-141 as a pharmacological probe.
| Receptor Subtype | Primary Expression | Research Relevance for PT-141 |
|---|---|---|
| MC1R | Melanocytes, immune cells | Pigmentation and inflammatory signaling studies |
| MC3R | Hypothalamus, limbic system | Energy homeostasis and autonomic modulation research |
| MC4R | Hypothalamus, brainstem, spinal cord | Central arousal, reward circuit, and autonomic studies |
| MC5R | Exocrine glands, peripheral tissues | Peripheral secretory function investigations |
Central Nervous System Signaling: What Preclinical Research Has Explored
The majority of published PT-141 research literature focuses on its CNS activity, particularly as it relates to hypothalamic and limbic system function. Preclinical animal studies have investigated how MC4R agonism modulates downstream dopaminergic activity — notably within the mesolimbic pathway — suggesting that the melanocortin system and dopamine signaling are functionally interconnected. This intersection has made PT-141 a useful probe for researchers studying motivational and reward-related circuits.
Studies using rodent models have examined c-Fos expression patterns following PT-141 administration, providing a neuroanatomical map of activated brain regions. Data from these experiments has pointed toward activity in the medial preoptic area (mPOA), paraventricular nucleus (PVN), and nucleus accumbens — regions with established roles in motivated behavior and autonomic regulation. Such findings have supported the hypothesis that the central melanocortin system interfaces meaningfully with circuits governing arousal and behavioral drive.
The broader context of nootropic and CNS signaling peptides in research continues to expand, and PT-141’s documented central activity makes it a relevant compound within that landscape, particularly for researchers mapping receptor-behavior relationships in the hypothalamus and limbic system.
Autonomic Nervous System Interactions
Beyond behavioral endpoints, PT-141 research has also examined its effects on autonomic nervous system parameters. Early studies in human subjects — conducted in the context of regulatory pharmacology — documented transient changes in blood pressure and heart rate following administration, findings that researchers have attributed to MC4R-mediated central autonomic modulation. These observations have provided useful reference points for researchers designing in vivo protocols involving the compound.
PT-141 vs. Melanotan II: A Research Comparison
Researchers frequently encounter both PT-141 and Melanotan II (MT-II) in the melanocortin peptide literature, and understanding their structural and functional distinctions is important for accurate interpretation of study data. While both compounds interact with melanocortin receptors and share a common peptide lineage, their pharmacological profiles differ in ways that are experimentally significant.
| Feature | PT-141 (Bremelanotide) | Melanotan II |
|---|---|---|
| Structure | Cyclic heptapeptide (lactam) | Cyclic heptapeptide (disulfide) |
| Receptor profile | MC1R, MC3R, MC4R, MC5R | MC1R, MC3R, MC4R, MC5R |
| Primary research focus | CNS signaling, autonomic modulation | Pigmentation, appetite, CNS effects |
| BBB penetration | Documented in preclinical models | Reported in animal studies |
| Regulatory status | Bremelanotide FDA-approved (clinical) | Research compound only |
| Metabolic stability | Enhanced (cyclic backbone) | Moderate |
The regulatory history of bremelanotide — and the body of formal clinical research it generated — has provided PT-141 researchers with a notably richer pharmacokinetic and pharmacodynamic dataset than is available for most research peptides. This makes PT-141 a comparatively well-characterized tool when designing receptor-focused studies.
PT-141 – 10MG Nasal Spray for research →
Hypothalamic Circuitry and Energy Homeostasis Research
One area of expanding research interest involves the overlap between melanocortin signaling and metabolic regulation. MC3R and MC4R are both expressed in hypothalamic nuclei with well-established roles in energy balance, and studies using melanocortin agonists — including PT-141 — have investigated how receptor activation in these regions influences food intake behavior and autonomic metabolic outputs in animal models.
This line of inquiry connects meaningfully to broader metabolic peptide research. For example, researchers examining MOTS-C’s role in mitochondrial and metabolic signaling or those studying GLP-1 receptor-mediated pathways may find the melanocortin axis a relevant parallel system for comparative mechanistic studies. The hypothalamus serves as an integrative hub for both GLP-receptor and melanocortin-receptor signaling, providing a compelling framework for multi-peptide research designs.
Some preclinical studies have also explored how MC4R signaling intersects with insulin sensitivity and glucose metabolism — further broadening the scope of PT-141’s utility as a research tool beyond its initial characterization in behavioral and autonomic contexts.
Laboratory Considerations for PT-141 Research
Formulation and Reconstitution
PT-141 is typically supplied in lyophilized form for research use, requiring reconstitution in bacteriostatic water or sterile saline prior to use in in vitro or in vivo protocols. The compound’s cyclic structure contributes to reasonable stability in solution when stored appropriately at low temperatures and protected from light. Researchers should consult certificates of analysis from their supplier to confirm purity specifications before use.
Nasal spray formulations have also been developed as a research delivery format for peptides with CNS-targeted applications, consistent with bremelanotide’s documented transmucosal absorption characteristics.
PT-141 – 10MG (lyophilized) for research →
Dosing Considerations in Preclinical Models
Published rodent studies investigating PT-141’s CNS activity have employed a range of doses, with behavioral endpoints typically assessed using established paradigms for motivation and arousal. Researchers designing new protocols should cross-reference dosing ranges against published literature and apply appropriate allometric scaling when translating between species. As with all research peptides, experimental rigor requires inclusion of vehicle controls and, where appropriate, receptor antagonist controls (e.g., SHU-9119 for MC4R blockade) to confirm receptor-specific effects.
Receptor Antagonist Pairings in Study Design
A hallmark of well-controlled melanocortin receptor research is the use of selective antagonists alongside agonists like PT-141 to confirm receptor specificity of observed effects. Studies pairing PT-141 with MC3R or MC4R antagonists have helped delineate the relative contribution of each receptor subtype to specific behavioral or physiological endpoints. This approach has been particularly informative in disambiguating the roles of MC3R versus MC4R in central arousal circuits.
PT-141 in the Context of the Broader Peptide Research Landscape
PT-141 occupies a distinctive niche within the research peptide landscape — one centered on central receptor pharmacology rather than tissue repair or metabolic regulation. Researchers who may be familiar with peptides like BPC-157 and TB-500 for tissue repair models or those investigating Selank’s anxiolytic and cognitive signaling properties will find PT-141 serves a complementary but distinct role — functioning as a probe for the melanocortin axis rather than growth factor or immune signaling pathways.
The broader categorization of research peptides by mechanism and target places PT-141 firmly in the GPCR agonist/CNS signaling tier, alongside compounds like Kisspeptin and Oxytocin — both of which interact with hypothalamic circuits through distinct but sometimes overlapping receptor systems. This classification is useful for researchers building multi-peptide experimental frameworks that interrogate different facets of central neuroendocrine regulation.
Oxytocin – 5MG Nasal Spray for research →
Kisspeptin – 10MG for research →
Where These Fit in Your Research Library
Researchers building a comprehensive peptide library for CNS signaling and neuroendocrine studies will find PT-141 pairs well with complementary compounds targeting adjacent receptor systems. Consider the following for a multi-mechanistic central signaling research approach:
- PT-141 – 10MG Nasal Spray — Melanocortin MC3R/MC4R agonist; CNS arousal and autonomic signaling studies
- Oxytocin – 5MG Nasal Spray — Hypothalamic neuropeptide; social behavior and autonomic regulation research
- Selank – 10MG Nasal Spray — Anxiolytic peptide analog; GABAergic and BDNF pathway investigations
Browse the full PT-141 research format options →
Summary: Key Takeaways for PT-141 Research
PT-141 (bremelanotide) is a well-characterized cyclic heptapeptide that functions as a melanocortin receptor agonist with particular affinity for MC3R and MC4R in the central nervous system. Its ability to cross the blood-brain barrier has made it a valuable pharmacological tool in preclinical research exploring hypothalamic signaling, autonomic modulation, and the intersection of melanocortin and dopaminergic pathways. Key points for researchers include:
- Receptor profile: Primary activity at MC3R and MC4R; documented binding at MC1R and MC5R
- CNS penetration: Crosses the blood-brain barrier in preclinical models, enabling central signaling research
- Research applications: Hypothalamic circuit mapping, autonomic modulation studies, behavioral paradigm research, receptor pharmacology
- Structural advantage: Cyclic backbone confers enhanced metabolic stability relative to linear MSH analogs
- Regulatory context: Active molecule (bremelanotide) has FDA-approved clinical form; PT-141 is used as a research compound in preclinical and in vitro laboratory contexts
- Study design note: Receptor antagonist controls (e.g., SHU-9119) are recommended for confirming MC4R-specific effects in in vivo protocols
As central melanocortin research continues to evolve — particularly at the intersection of neuroendocrine regulation, metabolic homeostasis, and motivational neuroscience — PT-141 remains a highly relevant tool compound for researchers seeking to interrogate these overlapping signaling systems with precision and specificity.
Sources & Further Reading
- Wessells H et al. — “Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction” — Journal of Urology (2000)
- Diamond LE et al. — “An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141)” — Journal of Sexual Medicine (2004)
- Giuliano F et al. — “Melanocortin receptor agonism and penile erection: role of peripheral and central mechanisms” — Neuroscience & Biobehavioral Reviews (1999)
- PubMed Search — Bremelanotide & Melanocortin Receptor Research (current literature)
- PubMed Search — PT-141 Central Nervous System Signaling Studies
