This is a working overview of MC4R agonist, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-12 and is reviewed periodically as new material appears.
Clinical research typically uses randomised, double-blind, placebo-controlled designs. The most common primary endpoint is the desire domain score of the Female Sexual Function Index, sometimes paired with a distress measure. Secondary outcomes include arousal, satisfaction, and event-based counts of satisfying sexual episodes. Across trials, average improvements are modest and individual responses vary widely. Whether benefits persist beyond a few months, and whether they depend on baseline hormone status, remain open questions rather than settled findings.
Melanocortin receptors form a family of five G-protein-coupled receptors designated MC1 through MC5. Bremelanotide binds most strongly at MC4R and MC1R, with weaker activity reported at MC3R and MC5R. MC4R is expressed in hypothalamic nuclei that coordinate energy balance and aspects of sexual behaviour. The prevailing interpretation is that central MC4R activation, rather than peripheral vascular effects alone, drives the reported changes in desire. This account remains partly inferential, since direct receptor-level measurement in living humans is not practical.
Handling procedures emphasize minimizing moisture uptake, since the dried solid is hygroscopic and can draw water when warmed to room temperature before a vial is opened. Laboratories record lot number, purity, counter-ion content, and residual solvent data supplied by the producer. Impurity profiles are compared run to run, and any shift in retention time or peak shape prompts re-verification against a reference standard. Certificates of analysis are treated as claims to be checked rather than accepted at face value.
Identity and purity testing for this peptide typically relies on reversed-phase high-performance liquid chromatography with ultraviolet detection, reported as area-percent purity. Mass spectrometry, usually in tandem mode, confirms molecular mass and supports quantification in biological matrices. Sequence confirmation may use peptide mapping after enzymatic digestion, while nuclear magnetic resonance and circular dichroism supply supplementary structural detail. No single technique establishes identity alone, so laboratories compare retention time, mass, and fragment pattern against a verified reference standard.
| Property | Value | Notes |
|---|---|---|
| Primary receptor targets | MC4R and MC1R | Agonist activity; MC3R and MC5R weaker |
| Route studied in trials | Subcutaneous injection | Intranasal form was not approved |
| Elimination half-life | Approximately 2–3 hours | Short relative to the dosing interval |
| Common analytical method | Liquid chromatography–tandem mass spectrometry | Used for peptide quantification in plasma |
| Reported adverse events | Nausea, flushing, headache | Transient blood pressure rise also noted |
Bremelanotide acts as a non-selective agonist at melanocortin receptors, with reported activity at MC1R, MC3R, MC4R and MC5R. The proposed basis for its central effects is activation of MC4R populations in the hypothalamus, a region associated with appetite and reproductive signalling. Because the peptide carries a net positive charge and polar side chains, it does not cross biological membranes freely, which is one reason oral administration is not the standard route. Effects generally appear within an hour of parenteral administration and are described as centrally mediated rather than peripheral.
Bremelanotide, developed under the code PT-141, is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone. Its structure is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, with a lactam bridge joining the aspartate and lysine side chains. The molecule has the formula C50H68N14O10 and a monoisotopic mass near 1025 daltons. It is commonly prepared as the acetate salt and appears as a white to off-white lyophilised powder in solid form. The free acid is the pharmacologically relevant species, while the counter-ion improves handling and dissolution.
Early research on PT-141 grew out of work on melanotan II, a related cyclic peptide studied for pigmentation. Investigators observed that centrally acting melanocortin agonists also influenced sexual behaviour in animal models, and the programme shifted toward that endpoint. A nasal formulation was evaluated in clinical trials but showed inconsistent absorption, and later studies used subcutaneous administration instead. Regulatory approval in the United States followed in 2019 for a defined population of premenopausal women with acquired, generalised hypoactive sexual desire disorder. That approval was specific to that group rather than a broad indication.
Development of the peptide passed through several delivery formats, including an intranasal version tested in early trials and an injectable version that entered later clinical study. Regulatory approval for a subcutaneous product in the United States was granted in 2019 after review of controlled trials in premenopausal women. Outside the clinic, the compound circulates in research and non-pharmaceutical markets under its code name, where identity and purity vary considerably between suppliers. Synonyms appearing across technical literature include bremelanotide, PT-141, and Palatin 141.
PT-141 is the research designation for bremelanotide, a synthetic cyclic heptapeptide developed as a melanocortin receptor agonist. The peptide contains seven amino acids with an internal lactam bridge that constrains the backbone into a stable ring. Cyclisation of this kind improves resistance to enzymatic degradation relative to linear analogues. The compound was first explored for effects on melanin production, because several melanocortin receptors influence pigmentation. Its later association with sexual desire emerged from observations made during that early work, and the molecule became the subject of a separate development programme.
Bremelanotide is a moderately large peptide with a molecular mass near 1025 daltons. In lyophilised form it appears as a white to off-white powder and is freely soluble in water and other polar solvents. The intact lactam ring is essential for receptor affinity, while linearised fragments bind far more weakly. Solutions are sensitive to extremes of pH and to prolonged exposure to light and heat, so handling typically involves buffered conditions and cold storage. Its short plasma half-life reflects rapid distribution and clearance rather than chemical breakdown inside the vial.
Development began with intranasal formulations investigated for erectile dysfunction, but blood pressure elevation limited that route and prompted a switch to subcutaneous delivery. Clinical testing then shifted toward hypoactive sexual desire disorder in premenopausal women, and a subcutaneous product received United States approval in 2019. Later trials examined other populations with mixed results, and questions about effect size, durability and patient selection remain open in the peer-reviewed literature. Research interest continues in parallel with the broader melanocortin field, where several synthetic analogues are studied together.
PT-141 is the research code for bremelanotide, a cyclic heptapeptide derived from alpha-melanocyte-stimulating hormone. The molecule belongs to the melanocortin receptor agonist family and shows highest affinity for the MC4 receptor subtype, with weaker activity at MC1, MC3 and MC5. Its structure retains the core His-Phe-Arg-Trp sequence that defines melanocortin recognition, while cyclization and terminal modifications improve metabolic stability relative to the parent hormone. Early work classified the compound as a centrally acting agent rather than a peripherally acting vasodilator, which shaped subsequent development priorities.
Receptor activation in hypothalamic and limbic circuits is the mechanism most often cited for the observed effects on sexual desire. Signalling through MC4R couples to Gs proteins and raises intracellular cyclic AMP, which in turn modulates dopaminergic tone in reward-related pathways. Because the peptide reaches the central nervous system after subcutaneous administration, peripheral vascular changes are regarded as secondary rather than primary. The precise neural circuits that translate receptor occupancy into behavioural change remain incompletely mapped, and published accounts describe the pathway in general terms rather than as a fully resolved sequence.
The molecular backbone consists of seven amino acid residues joined into a ring through a disulfide bridge. This cyclic conformation is critical for receptor binding. The sequence includes an acetylated N-terminus and an amidated C-terminus, modifications that improve resistance to enzymatic breakdown. One residue is in the D-configuration, a feature that further stabilizes the peptide against protease activity. Together, the ring structure and specific stereochemistry determine selectivity among melanocortin receptor subtypes.
Across literature and commercial listings, the substance appears under several names, including bremelanotide, PT-141, and various brand designations. A CAS registry number provides a unique identifier for the compound, aiding retrieval from chemical databases. Synonym lists may also contain early development codes and descriptive chemical names. When consulting sources, researchers need to confirm that the cited names refer to the same molecular structure to avoid confusion. Naming consistency matters especially when comparing analytical data across publications.
PT-141 is a synthetic cyclic heptapeptide whose development code is bremelanotide. It belongs to the class of melanocortin receptor agonists and acts by mimicking endogenous peptide hormones. The compound originated from research on melanotan II, where investigators exploring derivatives found distinct pharmacological features. Unlike the parent compound, PT-141 showed effects on pathways related to sexual desire and function in early studies, prompting its development as a separate candidate. Its molecular design aimed to separate receptor activity from pigmentary effects.
July 26: Order regulating the number of women accompanying the army. November 17 (Paris): Police prefect ordinance bans women from wearing men's clothing, including trousers, though permits can be granted. 1801
Detection of myositis-specific autoantibodies (MSAs), including anti-Mi-2, anti-NXP2, anti-TIF1-γ, anti-MDA5, and anti-SAE. These autoantibodies are considered pathogenic and are typically mutually exclusive, with most patients harboring only a single MSA. Muscle weakness in both thighs or both upper arms. Using a blood test, finding higher levels of enzymes found in skeletal muscle, including creatine kinase, aldolase, and glutamate oxaloacetate, pyruvate transaminases or lactate dehydrogenase. Using electromyography (testing of electric signalling in muscles), finding all three of: erratic, repetitive, high-frequency signals; short, low-energy signals between skeletal muscles and motor neurons that have multiple phases; and sharp activity when a needle is inserted into the muscle. Examining a muscle biopsy under a microscope demonstrating perifascicular atrophy, increased expression of type I interferon–inducible markers (predominantly in the perifascicular regions), mononuclear white blood cells between the muscle cells, and finding abnormal muscle cell degeneration and regeneration, dying muscle cells, and muscle cells being consumed by other cells (phagocytosis). Rashes typical of dermatomyositis, which include heliotrope rash, Gottron's sign, and Gottron's papules. The fifth criterion is what differentiates dermatomyositis from other forms of inflammatory myopathy. Patients with antisynthetase autoantibodies, such as anti-Jo-1, may also present with dermatomyositis-like skin manifestations.
In this pathway, PAH molecules bind to the aryl hydrocarbon receptor (AhR) and activate it as a transcription factor that increases production of the cytochrome enzymes. The activity of these enzymes may at times conversely protect against PAH toxicity, which is not yet well understood. Low molecular weight PAHs, with two to four aromatic hydrocarbon rings, are more potent as co-carcinogens during the promotional stage of cancer. In this stage, an initiated cell (a cell that has retained a carcinogenic mutation in a key gene related to cell replication) is removed from growth-suppressing signals from its neighboring cells and begins to clonally replicate. Low-molecular-weight PAHs that have bay or bay-like regions can dysregulate gap junction channels, interfering with intercellular communication, and also affect mitogen-activated protein kinases that activate transcription factors involved in cell proliferation. Closure of gap junction protein channels is a normal precursor to cell division. Excessive closure of these channels after exposure to PAHs results in removing a cell from the normal growth-regulating signals imposed by its local community of cells, thus allowing initiated cancerous cells to replicate. These PAHs do not need to be enzymatically metabolized first. Low molecular weight PAHs are prevalent in the environment, thus posing a significant risk to human health at the promotional phases of cancer.
==== January ==== On 3 January, four members of the "National Army" in Suwayda were attacked by mortars belonging to the General Security. On 11 January, the Syrian government forces launched attacks toward Suwayda from Kanaker and Tal Hadid, and four civilians were injured. The injured were identified as Kinan Adel Al-Badeeish, Sami Salman Allameh, Majd Firas Jazan and Haitham Hani Mazhar. On 24 January, the Syrian government forces reported the death of one of their members in clashes against the National Guard. The Syrian government forces also carried out a special operation in Suwayda to rescue three civilians kidnapped by the National Guard.
== History == Viracor-IBT was created through the merger of two specialty diagnostic testing labs, Viracor Laboratories and IBT Laboratories. Founded by Dr. Konstance Knox and Dr. Donald Carrigan in Milwaukee County in 2000, Viracor was among the first to commercially offer real-time quantitative PCR assays to diagnose patients with Adenovirus, BK virus and JC virus, among others. Founded in 1983, IBT was the first laboratory to offer a test to definitively diagnose autoimmune causes of chronic hives and developed the first commercially available test to measure pneumococcal antibodies. On 1 July 2014, Ampersand Capital Partners completed the sale of Viracor-IBT Laboratories to Eurofins Scientific for $255 million. The company continued to be known as Viracor-IBT.
Sources: en.wikipedia.org
Randomized controlled trials have found that higher dosages of CPA (e.g., 20 mg/day or 100 mg/day) added cyclically to a birth control pill containing ethinylestradiol and 2 mg/day CPA were no more effective or only marginally more effective in the treatment of severe hirsutism in women than the birth control pill alone. Maintenance therapy with lower doses of CPA, such as 25 mg/day, has been found to be effective in preventing relapse of symptoms of hirsutism. CPA has typically been combined with ethinylestradiol, but it can alternatively be used in combination with hormone replacement therapy dosages of estradiol instead. CPA at a dosage of 50 mg/day in combination with 100 μg/day transdermal estradiol patches has been found to be effective in the treatment of hirsutism similarly to the combination of CPA with ethinylestradiol. The efficacy of the combination of an estrogen and CPA in the treatment of hirsutism in women appears to be due to marked suppression of total and free androgen levels as well as additional blockade of the androgen receptor.
== Medical uses == In the US, sirolimus, as Rapamune, is indicated for the prevention of organ transplant rejection and for the treatment of lymphangioleiomyomatosis; and, as Fyarro, in the form of protein-bound particles, for the treatment of adults with locally advanced unresectable or metastatic malignant perivascular epithelioid cell tumour (PEComa). In the EU, sirolimus, as Rapamune, is indicated for the prophylaxis of organ rejection in adults at low to moderate immunological risk receiving a renal transplant and for the treatment of people with sporadic lymphangioleiomyomatosis with moderate lung disease or declining lung function; and, as Hyftor, for the treatment of facial angiofibroma associated with tuberous sclerosis complex.
Take white (Yemeni) alum, dissolve it and purify it by filtration. Then distil (green?) vitriol with copper-green (the acetate), and mix (the distillate) with the filtered solution of the purified alum, afterwards let it solidify (or crystallise) in the glass beaker. You will get the best qalqadis (white alum) that may be had. In an anonymous Latin work variously attributed to Aristotle (under the title Liber Aristotilis, 'Book of Aristotle'), to al-Razi (under the title Lumen luminum magnum, 'Great Light of Lights'), or to Ibn Sina, the author speaks of an 'oil' (oleum) obtained through the distillation of iron(II) sulfate (green vitriol), which was likely 'oil of vitriol' or sulfuric acid. The work refers multiple times to Jabir ibn Hayyan's Seventy Books (Liber de septuaginta), one of the few Arabic Jabir works that were translated into Latin. The author of the version attributed to al-Razi also refers to the Liber de septuaginta as his own work, showing that he erroneously believed the Liber de septuaginta to be a work by al-Razi. There are several indications that the anonymous work was an original composition in Latin, although according to one manuscript it was translated by a certain Raymond of Marseilles, meaning that it may also have been a translation from the Arabic. According to Ahmad Y. al-Hassan, three recipes for sulfuric acid occur in an anonymous Garshuni manuscript containing a compilation taken from several authors and dating from before c. 1100 AD. One of them runs as follows:
=== Legality of South West Africa, 1946–1960 === After World War II, Jan Smuts headed the South African delegation to the United Nations Conference on International Organization. As a result of this conference, the League of Nations was formally superseded by the United Nations (UN) and former League mandates by a trusteeship system. Article 77 of the United Nations Charter stated that UN trusteeship "shall apply...to territories now held under mandate"; furthermore, it would "be a matter of subsequent agreement as to which territories in the foregoing territories will be brought under the trusteeship system and under what terms". Smuts was suspicious of the proposed trusteeship, largely because of the vague terminology in Article 77. Heaton Nicholls, the South African high commissioner in the United Kingdom and a member of the Smuts delegation to the UN, addressed the newly formed UN General Assembly on 17 January 1946. Nicholls stated that the legal uncertainty of South West Africa's situation was retarding development and discouraging foreign investment; however, self-determination for the time being was impossible since the territory was too undeveloped and underpopulated to function as a strong independent state. In the second part of the first session of the General Assembly, the floor was handed to Smuts, who declared that the mandate was essentially a part of the South African territory and people.
motif Any distinctive or recurring sequence of nucleotides in a nucleic acid or of amino acids in a peptide that is or is conjectured to be biologically significant, especially one that is reliably recognized by other biomolecules or which has a three-dimensional structure that permits unique or characteristic chemical interactions such as DNA binding. In nucleic acids, motifs are often short (three to ten nucleotides in length), highly conserved sequences which act as recognition sites for DNA-binding proteins or RNAs involved in the regulation of gene expression.
Sources: en.wikipedia.org
== External links == INSL5 human gene location in the UCSC Genome Browser. INSL5 human gene details in the UCSC Genome Browser. Overview of all the structural information available in the PDB for UniProt: Q9Y5Q6 (Human Insulin-like peptide INSL5) at the PDBe-KB.
The Netherlands Ministry of Education funds most public universities. Dutch citizens and those from European Union countries pay an annual tuition fee for their first bachelor's or master's degree; the fee was €1,951 in 2015. Non-European Union students and students who want to complete a second bachelor's or master's degree pay a legal school fee. Annually, these legal school fees range between €7,000 for bachelor programs and €30,000 for master's programs in medicine. The Ministry of Education supervises all universities, including private institutions.
A newer process, solid oxide membrane technology, involves the electrolytic reduction of MgO. At the cathode, Mg2+ ion is reduced by two electrons to magnesium metal. The electrolyte is yttria-stabilized zirconia (YSZ). The anode is a liquid metal. At the YSZ/liquid metal anode O2− is oxidized. A layer of graphite borders the liquid metal anode, and at this interface carbon and oxygen react to form carbon monoxide. When silver is used as the liquid metal anode, there is no reductant carbon or hydrogen needed, and only oxygen gas is evolved at the anode. It was reported in 2011 that this method provides a 40% reduction in cost per pound over the electrolytic reduction method.
Coeliac disease is a systemic disorder, meaning it affects the entire body. Although many common symptoms of the disease are related to the gastrointestinal tract, those with coeliac disease may also experience symptoms and complications in other organs, known as extraintestinal manifestations. These manifestations may be related to malabsorption or systemic inflammation. Common extraintestinal manifestations of coeliac disease include headaches, fatigue, brain fog, muscle pain, and joint pain. Nutritional status in coeliac disease may be compromised due to lower intake, maldigestion, and malabsorption, leading to nutritional deficiencies. Common deficiencies in coeliac disease include iron, folate, zinc, vitamin D, and vitamin B12. Vitamin D deficiency can cause secondary hyperparathyroidism. Hyperoxaluria and kidney stones can be caused by malabsorption of fats, and peptides. Iron deficiency may lead to anaemia, which is one of the most common extraintestinal presentations of coeliac disease. Coeliac disease also often affects the bones, causing low bone mass density (osteopenia) and osteoporosis. Causes of bone changes in coeliac disease are believed to be caused by malabsorption, inflammation, and autoimmunity. If left untreated, coeliac disease can affect hormones, causing delayed periods or puberty and reproductive disorders. Coeliac disease is associated with infertility and complications during pregnancy such as intra-uterine growth restriction and spontaneous abortion.
{\displaystyle {\frac {\partial W}{\partial t}}+U{\frac {\partial W}{\partial X}}+W{\frac {\partial W}{\partial Z}}\ =-{\frac {1}{\rho _{o}}}{\frac {\partial p_{d}}{\partial Z}}+v\left({\frac {\partial ^{2}W}{\partial X^{2}}}+{\frac {\partial ^{2}W}{\partial Z^{2}}}\right)\ -g\left(\beta _{s}\nabla {S}-\beta _{T}\nabla {T}\right)}
Sources: en.wikipedia.org
Trial results generally show a small to moderate average improvement in desire scores relative to placebo. The distribution of responses is wide, and some participants show little measurable change. Group averages should not be read as a prediction for any single person.
Nausea, flushing, headache, and transient blood pressure elevation are the most frequently reported events. These typically appear shortly after dosing and are usually described as mild to moderate in severity. Safety data covering long periods of continuous use remain limited.
A short half-life means the compound clears from circulation within hours, so any effect is tied closely to dosing time. Accumulation between doses is therefore unlikely under the studied schedule. The practical consequence is that timing of administration shapes what observers record.
Chemical degradation such as hydrolysis and oxidation proceeds more slowly as temperature falls. Cold storage also limits microbial growth in reconstituted material. Repeated warming should be avoided because thermal cycling stresses the peptide.