bremelanotide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-03-02 and is reviewed periodically as new material appears.
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.
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.
Evidence outside the studied population is sparse. Trials have concentrated on premenopausal women with a defined diagnosis, and data for postmenopausal women, men, and people taking interacting medications remain limited. Non-prescription use of the peptide for comparable goals is widespread but is not supported by published controlled data. Observed changes in blood pressure have drawn attention to cardiovascular monitoring during use. The literature generally frames the compound as a targeted receptor agonist rather than a general libido enhancer, and basic questions about mechanism and long-term safety are unresolved.
Bremelanotide functions as an agonist at several melanocortin receptor subtypes, with the strongest functional activity reported at the MC4 subtype. MC4 receptors sit in hypothalamic circuits that influence appetite, energy balance, and components of sexual behaviour. Rodents lacking functional MC4 receptors show altered mating behaviour, which supports a role for this pathway in desire. The precise sequence of events connecting receptor activation to reported human effects remains only partly characterised. Because the same receptor family governs pigmentation and inflammatory signalling, selectivity is a recurring theme in pharmacological discussion.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Cyclic peptide | Melanocortin receptor agonist family |
| Molecular weight | Approximately 1025 Da | Free base form |
| Appearance | White to off-white powder | Lyophilized product |
| Solubility | Soluble in water | Also dissolves in polar organic solvents |
| Storage temperature | -20 degrees Celsius | Dry and protected from light |
After subcutaneous dosing, peak plasma concentrations appear within roughly one hour, and elimination is fast, with a half-life on the order of a few hours. Degradation is mainly proteolytic, and at least one circulating fragment retains receptor activity, so parent-drug levels alone do not describe total exposure. Clearance does not depend heavily on hepatic cytochrome enzymes, which lowers the likelihood of common metabolic interaction routes. Data in renal or hepatic impairment are limited. Repeated dosing does not appear to produce marked accumulation given the short half-life.
Reported pharmacodynamic effects include transient rises in blood pressure and heart rate, flushing, nausea and headache, appearing soon after dosing and resolving within hours. These responses were dose-related in early studies and shaped the label's cardiovascular cautions and blood pressure monitoring advice. Gastrointestinal upset is the most frequent reason cited for discontinuation in trials. Whether the vascular signal attenuates with repeated use is not settled. Central effects on desire are described as emerging over weeks rather than immediately, which points to a cumulative rather than acute process.
The compound binds several melanocortin receptor subtypes rather than a single target, with the strongest functional activity reported at MC4R and measurable activity at MC1R, MC3R and MC5R. MC4R populations are dense in hypothalamic nuclei that integrate energy balance, autonomic tone and reproductive behaviour, which is the anatomical basis for the proposed pro-desire effect. Because binding is not subtype-selective, pigmentary and vascular effects accompany central activity. Improving subtype selectivity is an active area of analogue design. Direct causal mapping from receptor occupancy to reported desire change in humans is not fully established.
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.
Through a combination of fortune and good political decisions, the Eastern Empire never experienced rebellious barbarian vassals or rule by barbarian warlords—the problems which ensured the downfall of the West. Zeno (r. 474–491) convinced the problematic Ostrogoth king Theodoric to take control of Italy from Odoacer; dying when the empire was at peace, he was succeeded by Anastasius I (r. 491–518). His belief in monophysitism brought occasional issues, but Anastasius was a capable administrator and instituted successful financial reforms including the abolition of the chrysargyron tax. He was the first emperor since Diocletian not to face any serious problems affecting the empire during his reign.
Stanton, along with 33 other Essendon players, was found guilty of using a banned performance-enhancing substance, thymosin beta-4, as part of Essendon's sports supplements program during the 2012 season. He and his team-mates were initially found not guilty in March 2015 by the AFL Anti-Doping Tribunal, but a guilty verdict was returned in January 2016 after an appeal by the World Anti-Doping Agency. He was suspended for two years which, with backdating, ended in November 2016; as a result, he served approximately fourteen months of his suspension and missed the entire 2016 AFL season. On 10 August 2016 Stanton re-committed to the Bombers on a one-year deal. Early in the 2017 season, Stanton played his 250th AFL game against the Brisbane Lions at the Gabba. On 24 August 2017, Stanton announced that he would retire at the end of the 2017 season.
=== Prostate cancer === In males aged 55 years old and over finasteride decreases the risk of low-grade prostate cancer but may increase the risk of high-grade prostate cancer and has no effect on overall survival. A 2010 review found a 25% reduction in the risk of prostate cancer with 5α-reductase inhibitors. A follow-up study of the Medicare claims of participants in a 10-year Prostate Cancer Prevention Trial suggests the reduction in prostate cancer is maintained even after discontinuation of treatment. However, 5α-reductase inhibitors have been found to increase the risk of developing certain rare but aggressive forms of prostate cancer (27% risk increase), although not all studies have observed this. No impact of 5-α-reductase inhibitor on survival has been found in people with prostate cancer.
Several species sometimes suffer from a wasting condition caused by Vibrio bacteria. A more widespread sea star wasting disease sporadically causes mass mortalities. The results of a 2025 study of starfish off the coast of central British Columbia suggest that those living in the fjords can better survive outbreaks of the disease due to the lower temperatures and higher salinity of their environment. The protozoan Orchitophrya stellarum is known to infect and damage the gonads of starfish. Starfish are vulnerable to high temperatures. Experiments have shown that the feeding and growth rates of Pisaster ochraceus reduce greatly when their body temperatures rise above 23 °C (73 °F) and that they die when their temperature rises to 30 °C (86 °F). This species has a unique ability to absorb seawater to keep itself cool when it is exposed to sunlight by a receding tide. It also appears to rely on its arms to absorb heat, so as to protect the central disc and vital organs. Starfish and other echinoderms can be vulnerable to marine pollution. The common starfish is considered to be a bioindicator species for marine ecosystems. A 2009 study found that P. ochraceus is unlikely to be affected by ocean acidification as severely as other marine animals with calcareous skeletons. In other groups, structures made of calcium carbonate are vulnerable to dissolution when the pH is lowered. Researchers found that when P. ochraceus were exposed to 21 °C (70 °F) and 770 parts per million of carbon dioxide (beyond rises expected in the next century), they were relatively unaffected.
== As a bioassay == Organisation for Economic Co-operation and Development and U.S. Environmental Protection Agency (US EPA) guidelines describe toxicity testing using L. gibba or L. minor as test organisms. Both of these species have been studied extensively for use in phytotoxicity tests. Genetic variability in responses to toxicants can occur in Lemna, and data are insufficient to recommend a specific clone for testing. The US EPA test uses aseptic technique. The OECD test is not conducted axenically, but steps are taken at stages during the test procedure to keep contamination by other organisms to a minimum. Depending on the objectives of the test and the regulatory requirements, testing may be performed with renewal (semistatic and flow-through) or without renewal (static) of the test solution. Renewal is useful for substances that are rapidly lost from solution as a result of volatilisation, photodegradation, precipitation, or biodegradation.
Sources: en.wikipedia.org
These errors were later corrected by the independent synthetic efforts of researchers at Tohoku University and Harvard University. In 1997, en route to the originally reported structure, researchers under the direction of Masahiro Hirama discovered that the spectroscopic data of the proposed chloroazatyrosyl (S)-α-amino acid derivative were not consistent with those of the degradation product characterized by Leet et al. Instead, an (R)-β-amino acid derivative was proposed and validated by the Hirama group. This revision led Hirama et al. to invert the other aglycone stereocenters as well, affording a revised structure of kedarcidin chromophore that differed only in the relative stereochemistry of the mycarose-bearing carbon, C10. Finally, in 2007, Myers and co-workers synthesized the structure proposed by Hirama et al.; the corresponding NMR spectroscopic data were distinct from that of the natural product, leading the Myers group to revise the stereochemistry of the mycarose-bearing carbon to 10-(S).
Prolyl endopeptidase is a large cytosolic enzyme that belongs to a distinct class of serine peptidases. It was first described in the cytosol of rabbit brain as an oligopeptidase, which degrades the nonapeptide bradykinin at the Pro-Phe bond. The enzyme is involved in the maturation and degradation of peptide hormones and neuropeptides such as alpha-melanocyte-stimulating hormone, luteinizing hormone-releasing hormone (LH-RH), thyrotropin-releasing hormone, angiotensin, neurotensin, oxytocin, substance P and vasopressin. PREP cleaves peptide bonds at the C-terminal side of proline residues. Its activity is confined to action on oligopeptides of less than 10 kD and it has an absolute requirement for the trans-configuration of the peptide bond preceding proline. Prolyl endopeptidases are involved in the maturation and degradation of peptide hormones and neuropeptides.
{\displaystyle {\begin{aligned}y:\ &\rho \left({\partial _{t}u_{y}}+u_{x}{\partial _{x}u_{y}}+u_{y}{\partial _{y}u_{y}}+u_{z}{\partial _{z}u_{y}}\right)\\&\quad =-{\partial _{y}p}+\mu \left({\partial _{x}^{2}u_{y}}+{\partial _{y}^{2}u_{y}}+{\partial _{z}^{2}u_{y}}\right)+{\frac {1}{3}}\mu \ \partial _{y}\left({\partial _{x}u_{x}}+{\partial _{y}u_{y}}+{\partial _{z}u_{z}}\right)+\rho g_{y}\\\end{aligned}}}
NASA engineers had not yet worked out the idiosyncrasies of orbital mechanics involved in rendezvous, which are counter-intuitive. Simply thrusting the spacecraft toward the target changed its orbital altitude and velocity relative to the target. When McDivitt tried this, he found himself moving away and downward, as the retrograde thrust lowered his orbit, increasing his speed. The stage was dumping its residual propellant, causing it to move around in various directions relative to the Gemini. There were only two running lights on the stage, which made it hard at times for McDivitt to determine its orientation. McDivitt concluded that a rendezvous target should have at least three lights. There was no radar on board Gemini 4 to give a precise range to the target, so the astronauts had to rely on their visual depth perception to estimate the range, and this differed for the two men. Initially McDivitt estimated the distance at 400–500 feet (120–150 m), while White believed that it was closer ("a little over 200 feet (61 m)"). At the worst point, McDivitt estimated it was about a half mile (800 meters) away, while White's estimate was three-quarters of a mile (1200 meters). McDivitt estimated that he was able to get as close as 200 feet (61 m), but now White's estimate was between 850 and 1,000 feet (260 and 300 m). After expending almost half his thruster fuel, McDivitt finally gave up, in order to concentrate on the more important EVA objective.
Sources: en.wikipedia.org
== History == Developed and proposed for the first time in England by Stephen Lewis and Ken Heaton at the University Department of Medicine, Bristol Royal Infirmary, it was suggested by the authors as a clinical assessment tool in 1997 in the Scandinavian Journal of Gastroenterology after a previous prospective study, conducted in 1992 on a sample of the population (838 men and 1,059 women), had shown an unexpected prevalence of defecation disorders related to the shape and type of stool. The authors of the former paper concluded that the form of the stool is a useful surrogate measure of colon transit time. That conclusion has since been challenged as having limited validity for Types 1 and 2; however, it remains in use as a research tool to evaluate the effectiveness of treatments for various diseases of the bowel, as well as a clinical communication aid.
== History == Carbamazepine was discovered by chemist Walter Schindler at J.R. Geigy AG (now part of Novartis) in Basel, Switzerland, in 1953. It was first marketed as a drug to treat epilepsy in Switzerland in 1963 under the brand name Tegretol; its use for trigeminal neuralgia (formerly known as tic douloureux) was introduced at the same time. It has been used as an anticonvulsant and antiepileptic in the United Kingdom since 1965, and has been approved in the United States since 1968. Carbamazepine was studied for bipolar disorder throughout the 1970s.
== Max Jaffe == Max Jaffe was a distinguished 19th-century German biochemist, pathologist, pharmacologist, and professor. He was born on July 25, 1841, in what was formerly Grünberg, Silesia and is now Zielona Góra, Poland. While attending medical school at the University of Berlin, he studied under Ludwig Traube and Wilhelm Kühne. Afterward, he worked as an assistant in a medical clinic in Königsberg. There, he co-authored a paper on putrid sputum with Ernst Viktor von Leyden that led to the discovery of certain characteristic putrid processes in the lungs. After earning his degree in internal medicine, he served in the Franco-Prussian War and was decorated with the Iron Cross Second Class. The title of Extraordinary Professor of Medicinal Chemistry was awarded to him in 1872 and the following year he became the first Ordinary Professor of Pharmacology at the University of Königsberg. He was promoted to director of the Laboratory for Medical Chemistry and Experimental Pharmacology in 1878 and became a member of the Deutsche Akademie der Naturforscher Leopoldina in 1882. Aside from studying creatinine, he is also known for discovering urobilin and urobilinogen in urine and found that these compounds originated in bile. He died on October 26, 1911, in Berlin and is buried in the Weißensee Cemetery.
Sources: en.wikipedia.org
It belongs to the melanocortin receptor agonist family of peptides. Its cyclic structure distinguishes it from linear peptides and shapes its receptor binding profile.
It emerged from research on melanotan II. Investigators exploring derivatives observed distinct pharmacological features related to sexual function.
Common names include bremelanotide and PT-141. Chemical databases may also list early development codes and descriptive names.
The approved formulation is given by subcutaneous injection and is used on an as-needed basis rather than on a fixed daily schedule. An intranasal version was studied earlier but did not reach the same stage of development. Route of delivery strongly affects how quickly the peptide appears in circulation.