If you have been reading about Bremelanotide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-06-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Cyclic heptapeptide | Synthetic analogue of alpha-MSH |
| Molecular formula | C50H68N14O10 | Acetate salt form commonly reported |
| Molecular mass | ~1025 Da | Monoisotopic value near 1025.2 |
| Key structural motif | Lactam bridge | Asp side chain to Lys side chain |
| Solid appearance | White to off-white powder | Lyophilised and hygroscopic |
The lactam ring that closes the peptide backbone improves resistance to exopeptidase attack, but the molecule stays susceptible to hydrolysis and oxidation once dissolved. Degradation accelerates with temperature, extreme pH, and light exposure, and repeated freeze-thaw cycles promote aggregation and material loss. Lyophilized powder held desiccated at or below minus twenty degrees Celsius is the common way to keep reference material. Reconstituted solutions are generally kept cold and used within a short window because their stability is far lower than that of the dry solid.
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.
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.
After subcutaneous administration, plasma concentrations rise within roughly thirty minutes and the elimination half-life is short, on the order of two to three hours. Reported physiological responses include transient increases in blood pressure and nausea, which tended to diminish with repeated dosing in trial settings. Because the peptide clears quickly, effects are not expected to persist long after a dose. Absorption from non-injected routes is poorly characterised, and nasal delivery produced variable plasma levels in older work.
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.
== Common applications == The focus of this section is on the recognised metalloids. Elements less often recognised as metalloids are ordinarily classified as either metals or nonmetals; some of these are included here for comparative purposes. Metalloids and their compounds are used in alloys, biological agents (toxicological, nutritional, and medicinal), catalysts, flame retardants, glasses (oxide and metallic), optical storage media and optoelectronics, pyrotechnics, semiconductors, and electronics.
=== Longevity === Giant tortoises are among the longest-lived vertebrate animals (over 100 years by some estimates) and have been used as a model for studying longevity. DNA analysis of the genomes of Lonesome George, the iconic last member of Chelonoidis abingdonii, and the Aldabra giant tortoise Aldabrachelys gigantea led to the detection of lineage-specific variants affecting DNA repair genes that might contribute to our understanding of increased lifespan.
A clinical trial that is carried out at more than one medical institution. (NCI) A clinical trial conducted according to a single protocol but at more than one site, and, therefore, carried out by more than one investigator. (ICH E6 and ICH E9) Multidisciplinary opinion
=== Marriages and children === Galloway has been married four times and has six children. In 1979, he married Elaine Fyffe, with whom he has a daughter. The couple separated in 1987 and divorced in 1999. In 1994, Galloway married Amineh Abu-Zayyad, a Palestinian biologist, in a non-legally binding Islamic ceremony; a legally binding civil ceremony followed in March 2000. Abu-Zayyad was granted a divorce in February 2009, after an estrangement of several years, on the grounds of "unreasonable behaviour"; her petition was not contested. Galloway married Rima Husseini, his former researcher, in a non-legally binding Islamic ceremony in 2005. Galloway had two sons with Husseini, who is from Lebanon. On 31 March 2012 he married his fourth wife, the Dutch–Indonesian anthropologist Putri Gayatri Pertiwi, then 27, in Amsterdam. The initial event was followed by a traditional Javanese wedding ceremony in Sumatra and a civil marriage at the House of Commons in September 2012. Pertiwi worked as a consultant for a Dutch research firm and as a co-presenter of Galloway's TV show Sputnik. The couple have three children.
=== Putative active functions === Treatment of childhood convulsion Analgesic activity and sedative function Anti-fatigue effects Antitumor activity Amelioration of renal malfunction Immunomodulatory effects Immunoregulatory
Sources: en.wikipedia.org
affected relative pair Any pair of organisms which are related genetically and both affected by the same trait. For example, two cousins who both have blue eyes are an affected relative pair since they are both affected by the allele that codes for blue eyes.
Serine is important in metabolism in that it participates in the biosynthesis of purines and pyrimidines. It is the precursor to several amino acids including glycine and cysteine, as well as tryptophan in bacteria. It is also the precursor to numerous other metabolites, including sphingolipids and folate, which is the principal donor of one-carbon fragments in biosynthesis.
=== Etymology and nomenclature === The term psychedelic was coined by the psychiatrist Humphrey Osmond during written correspondence with author Aldous Huxley (written in a rhyme: "To fathom Hell or soar angelic/Just take a pinch of psychedelic.") and presented to the New York Academy of Sciences by Osmond in 1957. It is irregularly derived from the Greek words ψυχή (psychḗ, meaning 'mind, soul') and δηλείν (dēleín, meaning 'to manifest'), with the intended meaning "mind manifesting" or alternatively "soul manifesting", and the implication that psychedelics can reveal unused potentials of the human mind. The term was loathed by American ethnobotanist Richard Schultes but championed by American psychologist Timothy Leary. Aldous Huxley had suggested his own coinage phanerothyme (Greek phaneroein- "to make manifest or visible" and Greek thymos "soul", thus "to reveal the soul") to Osmond in 1956. Recently, the term entheogen (meaning "that which produces the divine within") has come into use to denote the use of psychedelic drugs, as well as various other types of psychoactive substances, in a religious, spiritual, and mystical context. In 2004, David E. Nichols wrote the following about the nomenclature used for psychedelic drugs:
Jobe Watson (born 8 February 1985) is a former professional Australian rules footballer who played for the Essendon Football Club in the Australian Football League (AFL). Watson, the son of three-time Essendon premiership champion Tim Watson, was drafted by Essendon under the father–son rule in the 2002 national draft, and went on to become one of the best midfielders of the modern era. A dual All-Australian and three-time Crichton Medallist, he captained Essendon from 2010 to early 2016, and was the face of the Essendon playing group during the most turbulent period in the club's history. Watson was one of thirty-four players suspended as part of the Essendon Football Club supplements saga for using the banned performance-enhancing substance Thymosin beta-4 during the 2012 AFL season. He originally won that season's Brownlow Medal as the league's best and fairest player, but was later ruled ineligible in 2016 as a result of the suspension and subsequently handed back the medal. Watson was suspended for the entire 2016 AFL season, before returning the following year; he then played for one more season before retiring. Watson is currently an AFL commentator for the Seven Network, following in the footsteps of his father Tim.
Sources: en.wikipedia.org
However, by careful optimization of instrument parameters which cause ion heating, hydrogen scrambling can be minimized to a degree which preserves the solution phase isotopic labeling until fragmentation can be performed using a technique where scrambling does not occur. More recently, ultraviolet photodissociation (UVPD) has also been investigated as a possible fragmentation technique to localize deuterium within peptides and proteins. In this regard, the conclusions have been mixed, while it is possible to obtain UVPD fragments which has not undergone scrambling under certain conditions, others have shown that scrambling can occur for both peptides and proteins during the UVPD fragmentation step itself. The theory consolidating these apparent contradictions has to do with the dual fragmentation pathway that may arise from UV irradiation of peptides and proteins, i.e. direct and statistical dissociation. That is, if experimental conditions favor direct dissociation and the precursor ion is kept at low internal energies before and during fragmentation the deuterium level of the resulting fragments will correspond to the non-scrambled precursor. However, experimental conditions may favor statistical dissociation during UV irradiation, especially at long irradiation times and low gas pressure, leading to internal conversion of the electronic excitation energy contributed by the UV photons. The result is vibrational excitation of the irradiated molecule which in turn undergo scrambling.
=== Cryogenics === The branches of engineering that involve the study of very low temperatures (ultra low temperature i.e. below 123 K), how to produce them, and how materials behave at those temperatures.
=== Improved radial tires === Goodyear Tire and Rubber Company developed a fibrous material, five times stronger than steel, for NASA to use in parachute shrouds to soft-land the Viking Lander spacecraft on the Martian surface. Recognizing the durability of the material, Goodyear expanded the technology and went on to produce a new radial tire with a tread life expected to be 10,000 miles (16,000 km) greater than conventional radials.
=== Economic Sciences === The medal for the Nobel Memorial Prize in Economic Sciences was designed by Gunvor Svensson-Lundqvist in 1968. The obverse of the medal depicts Alfred Nobel and the words "Sveriges Riksbank till Alfred Nobels Minne 1968" ("The Sveriges Riksbank, in memory of Alfred Nobel, 1968") with the symbol of the Sveriges Riksbank, the horn of plenty, displayed below. The name of the recipient is inscribed on the edge of the medal. The reverse features the emblem of the Royal Swedish Academy of Sciences, the North Star, in a design from 1815. "Kungliga Vetenskaps Akademien" ("The Royal Swedish Academy of Sciences") is inscribed around the edge of the star. It is the only medal without a quotation on its reverse. Since 2012 the economics medal has been manufactured by Svenska Medalj in Eskilstuna.
Since then, the species name Naja/Hoplocephalus bungaroides, originally coined for the king cobra and improperly assigned to the broad-headed snake, became conflated with the broad-headed snake and used as the type species of Hoplocephalus, while the species name Naja bungarus was treated as a junior synonym of the king cobra (until its revival as the species name for the Sunda king cobra in 2024). This longstanding discrepancy, which breaks the principle of priority, was overlooked for nearly two centuries and only discovered in 2024. Due to the long presence of the names Ophiophagus hannah and Hoplocephalus bungaroides in the literature, which would be upended if these two species were reclassified based on this issue, it was decided to maintain the longstanding scientific names for both taxa and designate a new, accurate type specimen for the broad-headed snake.
Sources: en.wikipedia.org
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.
The two compounds share the same cyclic core and are both non-selective melanocortin agonists. They differ chiefly at the C-terminus, where bremelanotide carries a free carboxylic acid and melanotan II a terminal amide.
Receptor binding profiles are well characterised in vitro, but the downstream pathway linking MC4R activation to behavioural effects is not fully mapped. Several intermediate neural circuits have been proposed without definitive confirmation.
It belongs to the melanocortin receptor agonist family of peptides. Its cyclic structure distinguishes it from linear peptides and shapes its receptor binding profile.