melanocortin receptor comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Early clinical work used an intranasal formulation, and later programmes switched to subcutaneous delivery for more consistent absorption. A subcutaneous product received regulatory approval in the United States in 2019 for premenopausal women with acquired, generalised hypoactive sexual desire disorder. Approval followed phase 3 trials in which active treatment separated from placebo on desire and distress measures, though the average difference was modest. Labeling carries a caution about transient blood pressure elevation, so cardiovascular history is assessed before prescribing. Questions about durability of benefit beyond several months remain open.
Published discussion sits at the intersection of peptide chemistry, neuroendocrinology and sexual medicine. Trial reports emphasise change scores on validated instruments, while mechanistic papers focus on hypothalamic circuits and receptor selectivity. Because placebo response in this field is large, effect sizes are usually reported with confidence intervals rather than as isolated averages. Reviews note that female and male data sets are not interchangeable and should be read separately. Diagnostic terminology has been revised over time, which complicates comparison between older and newer studies.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-MSH |
| Molecular mass | Approximately 1025 Da | Peptide-scale molecule |
| Route | Subcutaneous injection | Intranasal form used in early research |
| Common synonyms | PT-141; bremelanotide acetate | Research code and salt form |
| Typical storage | 2-8 °C, protected from light | Unopened vial condition |
The melanocortin system comprises five G protein-coupled receptors, designated MC1 through MC5, that signal mainly through cyclic AMP accumulation. MC1R and MC2R are associated with pigmentation and adrenal steroid production, while MC3R and MC4R are expressed in the central nervous system and influence energy balance and behavior. MC5R appears in exocrine tissues. Natural agonists include alpha-melanocyte-stimulating hormone and adrenocorticotropic hormone, and endogenous antagonists such as agouti-related protein modulate the same sites. This receptor family provides the framework within which bremelanotide activity is described.
Bremelanotide acts as an agonist at several melanocortin receptors, with the strongest reported activity at MC4R and measurable activity at MC1R and MC3R. Because MC4R is expressed in hypothalamic and limbic circuits, the proposed mechanism links receptor activation to modulation of central pathways involved in desire rather than to direct effects on peripheral genital tissue. The precise downstream steps remain incompletely characterized, and evidence for the involvement of specific neurotransmitters is suggestive rather than settled. Nausea and blood pressure elevation reported during trials are consistent with melanocortin signaling outside the intended target circuit.
Compared with melanotan II, bremelanotide is a smaller cyclic peptide with a more constrained backbone, which affects receptor selectivity and metabolic stability. Published descriptions give a plasma half-life on the order of a few hours after subcutaneous administration, with elimination through hepatic and renal routes and limited plasma protein binding. Central access is inferred from effects observed in animal models, although direct measurement in humans is limited. Handling and storage requirements follow from the peptide backbone, which is susceptible to hydrolysis and oxidation.
=== Preclinical === AM-510 – undefined mechanism of action – opioid-related disorders ATI-1013 – monoclonal antibody against nicotine – smoking withdrawal CTRX-1001 – immunostimulant – opioid-related disorders CTRX-2001 – immunostimulant – opioid-related disorders Cyclobenzaprine (KRL-102; TNX-102; Tonmya; VLD-cyclobenzaprine) – tricyclic antidepressant (various actions) – alcoholism Cyproheptadine/prazosin (KT-110; Periactine/Alpress) – combination of cyproheptadine (various actions) and prazosin (α1-adrenergic receptor antagonist) – cocaine-related disorders Dimethyltryptamine (DMT; EBRX-101) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and serotonergic psychedelic – alcoholism EQL-101 – undefined mechanism of action (non-hallucinogenic non-cardiotoxic ibogaine derivative) – substance use disorders Flumazenil/naloxone transdermal patch (MX-1607; RescuePatch) – combination of flumazenil (GABAA receptor negative allosteric modulator/benzodiazepine antagonist) and naloxone (opioid receptor antagonist) – substance-related disorders GM-3009 – κ-opioid receptor agonist (noribogaine analogue) – opioid-related disorders INDV-1000 (GABAB PAM) – GABAB receptor positive allosteric modulator – substance-related disorders KB-128 – serotonin 5-HT2C receptor G protein-biased agonist, serotonin 5-HT2A and 5-HT2B receptor antagonist – alcoholism LPH-48 – undefined mechanism of action and serotonergic psychedelic ((shorter-acting LPH-5 analogue) – alcoholism M-101 – GABA receptor antagonist – substance-related disorders 5-Methoxy-2-aminoindane (MEAI; 5-MeO-AI; CMND-100) – serotonin–norepinephrine releasing agent – cocaine-related disorders Metyrapone/oxazepam (EMB-001C; EMB-001) – combination of metyrapone (11β-hydroxylase inhibitor and cortisol synthesis inhibitor) and oxazepam (benzodiazepine/GABAA receptor positive allosteric modulator) – substance-related disorders Midomafetamine microneedle transdermal patch (MDMA; ecstasy) – serotonin, norepinephrine, and dopamine releasing agent, weak serotonin 5-HT2 receptor agonist, entactogen – substance-related disorders Naltrexone controlled-release (BICX101, BICX-101) – opioid receptor antagonist – alcoholism, opioid-related disorders Nicotine degrading enzyme (ATI-3009; NicA2; NicA2-J1) – enzyme – smoking withdrawal PPL-138 (BU10038, BU-10038) – nociceptin receptor agonist, μ-opioid receptor agonist, opioid peptide agonist – alcoholism, cocaine-related disorders PSIL-001 (DMT analogue) – non-hallucinogenic serotonin 5-HT1 receptor modulator – substance-related disorders PSIL-002 (DMT analogue) – non-hallucinogenic serotonin 5-HT1 receptor modulator – substance-related disorders Psilacetin (O-acetylpsilocin; 4-AcO-DMT) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, serotonergic psychedelic – substance-related disorders Pudafensine (IP-2015; IP-2017; IPNP-2015; IPTN-2021) – serotonin–norepinephrine–dopamine reuptake inhibitor – substance-related disorders Research programme: psychedelic-based neurological therapeutics - Psilera – undefined mechanism of action and serotonergic psychedelics – alcoholism Research programme: psychoplastogen therapeutics - Collaborations Pharmaceuticals – undefined mechanism of action – opioid-related disorders SVN-015 – serotonin–dopamine reuptake inhibitor – substance-related disorders SXC-2023 – cystine–glutamate antiporter (SLC7A11; System xc- or Sxc) activator – cocaine-related disorders, smoking withdrawal [15] [16] TACT411 – serotonin 5-HT1B receptor modulator and monoamine transporter modulator – alcoholism TACT523 – undefined mechanism of action – alcoholism TACT833 – serotonin 5-HT1B receptor modulator and monoamine transporter modulator – alcoholism VS-01 (VS-01-HAC) – ammonia scavenger – substance-related disorders
Most Moluccans in northern Maluku (present-day province of North Maluku) are Muslim. Central and southern Maluku (present-day province of Maluku) have approximately equal numbers of Muslims and Christians. There is significant number of native Hindus (Tanimbar Kei people) living in the Kei Islands, which is a predominantly Catholic region. This is because, according to oral traditions, their ancestors came from Bal (Bali) during the Majapahit era. Additionally, they practice local customary law called Larvul Ngabal (transl. "red blood and spear from Bali"). The most common religion amongst Moluccans in the Netherlands is Protestantism, followed by Islam.
B1007 provides a road link to Basildon, via the A127; it passes from just south of the town centre as Laindon Road, then Sun Corner, and northwards as Billericay's High Street and Stock Road. The road continues north to Chelmsford, via the village of Stock and an interchange to the A12 A129 provides an east-west link between Hadleigh, Wickford and Shenfield.
Sources: en.wikipedia.org
=== Public awareness === Public awareness of the disease, which is spread through the exchange of bodily fluids, is not as high as it is for HIV and AIDS. In some rural areas, doctors have reused syringes and unknowingly spread the disease, particularly among children.
== Brand names == Brand names for Oxymetazoline include Afrin, ClariClear, Dristan, Drixine, Drixoral, Nasivin, Nasivion, Nezeril, Nostrilla, Logicin, Vicks Sinex, Visine L.R., Sudafed OM, Otrivin, Oxy, SinuFrin, Vicks Sinex Severe (Spray), and Mucinex Sinus-Max. A topical cream formulation is sold under the brand name Rhofade. Oxymetazoline ophthalmic solution for the treatment of acquired blepharoptosis is marketed as Upneeq. In the United Arab Emirates, oxymetazoline nasal sprays are sold under imported brand names such as Otrivin. The UAE does not manufacture oxymetazoline but domestic pharmaceutical companies such as Julphar produce xylometazoline, a structurally related imidazoline decongestant.
The two substrates of this enzyme are galactitol-1-phosphate and oxidised nicotinamide adenine dinucleotide (NAD+). Its 3 products are L-tagatose 6-phosphate (shown in its open-chain keto form), reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is galactitol-1-phosphate:NAD+ oxidoreductase. This enzyme participates in galactose metabolism. It employs one cofactor, zinc.
Sources: en.wikipedia.org
It is a synthetic cyclic peptide that activates melanocortin receptors. It is given by injection and was approved in the United States in 2019 for a specific low-desire diagnosis in premenopausal women. It is not a hormonal therapy.
Earlier approaches were largely hormonal or psychological in focus, whereas this compound acts on central melanocortin signalling. It is not a vasodilator and does not share the mechanism of phosphodiesterase inhibitors. Head-to-head comparative data are limited.
Placebo responses in desire trials are large, so the average drug-placebo separation is small. Reporting therefore relies on validated questionnaires with statistical ranges. Individual responses vary widely.
PT-141 was the development code used for bremelanotide during its preclinical and early clinical programme. The peptide is now generally referred to by its international nonproprietary name.