PT-141 Research Compound

Q: What is PT-141 (Bremelanotide)?

PT-141, also known by the INN Bremelanotide, is a cyclic heptapeptide melanocortin receptor agonist. It is derived from Melanotan II via structural modification and is classified by CAS number 189691-06-3. Molecular formula: C50H68N14O10. Molecular weight: approximately 1025 Da. PT-141 has been examined in published research as a melanocortin receptor agonist with documented activity at MC3R and MC4R subtypes in preclinical models. For research use only. Not for human use.

Q: How does PT-141 differ from Melanotan II in research?

Both PT-141 (Bremelanotide) and Melanotan II (MT-II) are melanocortin receptor agonists structurally related to alpha-MSH. Published research has examined key differences in their receptor selectivity profiles: Melanotan II demonstrates broader activity across MC1R, MC3R, MC4R, and MC5R subtypes, while peer-reviewed literature suggests PT-141 exhibits a narrower receptor selectivity profile with activity concentrated at MC3R and MC4R in preclinical models. This distinction has been an area of interest in receptor selectivity research within the melanocortin system. For research use only.

Chemical Identity

What Is PT-141?

PT-141, designated by the International Nonproprietary Name Bremelanotide, is a synthetic cyclic heptapeptide classified as a melanocortin receptor agonist. It is structurally derived from Melanotan II through modification of the C-terminal residue from an amide to a hydroxyl group and cyclization, resulting in a compound with an altered receptor interaction profile relative to its parent molecule. CAS number: 189691-06-3.

Common Name	PT-141 / Bremelanotide
CAS Number	189691-06-3
Molecular Formula	C₅₀H₆₈N₁₄O₁₀
Molecular Weight	~1025 Da
Peptide Class	Cyclic heptapeptide
Receptor Class	Melanocortin receptor agonist
Primary Targets (Research)	MC3R, MC4R
Parent Compound	Melanotan II (MT-II)
Research Context	Melanocortin receptor pathway research, CNS receptor mechanism research, hypothalamic pathway research in preclinical models

Melanocortin System Context

PT-141 belongs to the melanocortin peptide family alongside alpha-MSH, ACTH, and related synthetic analogs. Peer-reviewed literature has investigated MC3R and MC4R as G protein-coupled receptors with expression patterns in the hypothalamus and central nervous system, making them subjects of ongoing CNS peptide receptor research in preclinical models. PT-141 is used in this research context as a selective agonist tool compound.

Published Research

Research Background

Peer-reviewed literature has examined PT-141 across multiple domains of melanocortin receptor biology. The compound's cyclic structure and receptor selectivity profile have made it a useful tool compound for preclinical receptor mechanism investigations. A full index of published literature is available via PubMed (bremelanotide + melanocortin).

Research Area 01

MC3R / MC4R Receptor Mechanism Research

Published research has examined PT-141's binding affinity and functional activity at melanocortin receptor subtypes MC3R and MC4R. Peer-reviewed literature has investigated downstream G protein-coupled signaling cascade engagement, cAMP pathway modulation, and receptor occupancy kinetics in experimental systems utilizing this compound as an agonist tool.

Research Area 02

Hypothalamic Pathway Research in Preclinical Models

Peer-reviewed literature has investigated hypothalamic melanocortin pathway signaling using MC3R/MC4R agonists including PT-141 in rodent models. This research has examined receptor expression patterns in hypothalamic nuclei, peptide penetration of CNS compartments, and pathway-level outcomes in preclinical experimental contexts.

Research Area 03

CNS Peptide Receptor Research

The central nervous system expression of MC3R and MC4R has been an active area of preclinical investigation. Published research has examined cyclic peptide access to CNS receptor compartments, blood-brain barrier considerations relevant to melanocortin agonist research, and receptor subtype distribution mapping in animal model tissue studies.

Research Area 04

Melanocortin System Research in Preclinical Models

The broader melanocortin system — encompassing MC1R through MC5R receptor subtypes, their endogenous agonists (alpha-MSH, beta-MSH, ACTH), and the role of inverse agonists — has been studied in preclinical models. PT-141 has been employed as a research tool compound to probe discrete components of this system, particularly at MC3R and MC4R.

Research Area 05

Receptor Selectivity Research

Peer-reviewed literature has investigated the receptor selectivity profile of PT-141 relative to other melanocortin agonists including alpha-MSH, ACTH fragments, and Melanotan II. Comparative binding studies and functional selectivity assays examining MC receptor subtype discrimination have been a recurring theme in published melanocortin pharmacology research involving this compound.

PubMed Literature Index

The indexed body of peer-reviewed literature on PT-141 / Bremelanotide is accessible at pubmed.ncbi.nlm.nih.gov/?term=bremelanotide+melanocortin. All referenced research pertains to in vitro or preclinical (animal model) findings. For research use only.

Sequence Labs Supply

PT-141 from Sequence Labs

Sequence Labs supplies PT-141 (Bremelanotide) as a lyophilized research peptide, independently verified by Krause Analytical (Austin, TX) via HPLC and mass spectrometry. COA authentication is available through the Finnrick Pulse platform. The catalog is reviewed by Sabrina Runbeck, PA-C.

PT-141 · Bremelanotide

~$45–$65

Lyophilized research vial
HPLC + MS verified
Krause Analytical · Austin, TX
COA via Finnrick Pulse
For research use only

View on Products Page

HPLC + Mass Spec Dual-method verification on every batch via Krause Analytical

Finnrick Pulse COA Batch-specific certificate, publicly verifiable

Sabrina Runbeck, PA-C DEA-registered practitioner catalog review

≥98–99% Purity Verified, not just stated

View COA Library

Research Preparation Reference

Reconstitution Reference

The following represents a general reference for preparing a PT-141 research sample from a lyophilized vial. All preparation should be conducted within the procedures and protocols of your licensed research context. For research use only. Not for human use.

Research Use Only

This reconstitution reference is provided strictly for qualified research personnel preparing experimental samples in a licensed research setting. Sequence Labs does not provide preparation guidance for any human use application. All quantities, concentrations, and preparation parameters are the sole responsibility of the supervising researcher and their approved protocol.

Allow to Reach Room Temperature

Remove the PT-141 research vial from cold storage and allow it to equilibrate to room temperature before opening. This minimizes condensation and thermal shock to the lyophilized peptide matrix.
Introduce Solvent Against the Vial Wall

Using a sterile syringe, slowly introduce bacteriostatic water down the inner wall of the research vial. Do not introduce solvent directly onto the lyophilized cake, as this can affect peptide integrity and dissolution characteristics.
Swirl — Do Not Shake

Gently swirl the vial to facilitate dissolution of the lyophilized research sample. Do not vortex or shake vigorously, as mechanical agitation may affect the structural integrity of the cyclic peptide.
Allow Full Dissolution

Allow the research sample to dissolve completely before proceeding. PT-141 lyophilized material should dissolve readily in bacteriostatic water at room temperature. If particulate remains, consult your research protocol before proceeding.
Store and Use Per Research Protocol

Store the reconstituted research preparation at 2–8 °C and use within the timeframe specified in your approved research protocol. Lyophilized (unreconstituted) vials should be stored as specified on the product COA. For research use only.

Solvent Note

Bacteriostatic water (0.9% benzyl alcohol in sterile water) is the standard research solvent referenced in published literature for melanocortin peptide research sample preparation. The choice of solvent and concentration should be determined by the supervising researcher in accordance with the specific experimental protocol. For research use only.

Comparative Research Context

PT-141 vs. Melanotan II

PT-141 (Bremelanotide) and Melanotan II are structurally related melanocortin receptor agonists that have been examined in published research as distinct research tool compounds. The following comparison reflects documented differences in their chemical structure and receptor selectivity profiles as reported in peer-reviewed literature.

Research Context Comparison

Two Melanocortin Agonists — Different Selectivity Profiles

Both PT-141 and Melanotan II are synthetic analogs structurally related to alpha-MSH. Published research has documented that Melanotan II (a cyclic heptapeptide lactam analog) demonstrates broad melanocortin receptor activity across MC1R, MC3R, MC4R, and MC5R subtypes in experimental models.

PT-141 (Bremelanotide) was derived from Melanotan II through structural modification — the conversion of the C-terminal amide to a hydroxyl group shifts the compound's receptor selectivity profile. Peer-reviewed literature has investigated PT-141's activity as more concentrated at MC3R and MC4R relative to the broader subtype coverage observed with MT-II in comparable assay systems.

This receptor selectivity distinction has been an area of active investigation in melanocortin pharmacology research, particularly in CNS-focused preclinical studies examining hypothalamic pathway biology. Both compounds are available from Sequence Labs for qualified melanocortin receptor research. For research use only.

Research Parameter	PT-141 (Bremelanotide)	Melanotan II (MT-II)
CAS Number	189691-06-3	121062-08-6
Peptide Class	Cyclic heptapeptide	Cyclic heptapeptide lactam
Structural Feature	C-terminal hydroxyl; derived from MT-II	Lactam bridge; alpha-MSH analog
Primary Receptors (Research)	MC3R, MC4R (primary focus)	MC1R, MC3R, MC4R, MC5R (broader)
Research Context	Hypothalamic/CNS pathway research, selective MC3R/MC4R studies	Melanocortin system broad-spectrum research, pigmentation pathway research
Available at Sequence Labs	Yes — see products.html	Yes — MT-2 (Melanotan II)

Common Questions

Frequently Asked Questions

What is PT-141 (Bremelanotide)?

PT-141, also referred to by the INN Bremelanotide, is a synthetic cyclic heptapeptide classified as a melanocortin receptor agonist. CAS number 189691-06-3. Molecular formula C₅₀H₆₈N₁₄O₁₀, molecular weight approximately 1025 Da. It is derived from Melanotan II and has been investigated in published research as a tool compound for melanocortin receptor pathway studies, with documented activity at MC3R and MC4R in preclinical models. For research use only. Not for human use.

What receptor does PT-141 target in research models?

Peer-reviewed literature has investigated PT-141's activity primarily at melanocortin receptor subtypes MC3R and MC4R — G protein-coupled receptors with documented expression in hypothalamic and CNS tissue in preclinical models. Published research has examined receptor binding affinity, selectivity relative to other melanocortin receptor subtypes, downstream signaling cascade engagement, and pathway-level outcomes in experimental systems. For research use only.

How does PT-141 differ from Melanotan II in research contexts?

Both compounds are melanocortin receptor agonists structurally related to alpha-MSH. The key distinction documented in peer-reviewed literature is receptor selectivity: Melanotan II demonstrates activity across MC1R, MC3R, MC4R, and MC5R in experimental systems, while PT-141's receptor selectivity profile in published research is concentrated at MC3R and MC4R. This makes PT-141 a more selective tool compound for discrete hypothalamic and CNS receptor pathway studies. For research use only.

What sizes does Sequence Labs carry for PT-141?

Sequence Labs carries PT-141 (Bremelanotide) as a lyophilized research vial. Current sizing and pricing (~$45–$65) is listed on the Products page. All research vials are independently tested by Krause Analytical (Austin, TX) via HPLC and mass spectrometry, with batch-specific COAs available and verifiable through Finnrick Pulse. The catalog is reviewed by Sabrina Runbeck, PA-C. For research use only.

How is PT-141 reconstituted for research use?

To prepare a PT-141 research sample: (1) Allow the vial to reach room temperature. (2) Introduce bacteriostatic water slowly down the inner wall of the vial — not directly onto the lyophilized cake. (3) Swirl gently — do not shake. (4) Allow complete dissolution. (5) Store at 2–8 °C per your approved research protocol. All preparation should occur within a licensed research setting under appropriate protocol oversight. For research use only. Not for human use.

Is PT-141 from Sequence Labs for human use?

No. PT-141 (Bremelanotide) supplied by Sequence Labs is strictly for in vitro and preclinical research use only. It is not approved by the FDA for any therapeutic application under Sequence Labs' supply context and is not intended for human consumption, self-experimentation, or clinical use outside of properly approved and supervised research protocols. Sequence Labs products are sold exclusively to licensed researchers, qualified institutions, and registered professionals for research purposes only.

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