This is a working overview of melanocortin, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
PT-141 is the original development code for bremelanotide, a synthetic peptide first studied as a potential tanning and sexual-response agent in the 1990s. Researchers at a small American biotechnology firm designed it as a shortened analogue of melanotan II, which itself came from work on alpha-melanocyte-stimulating hormone. Early screening focused on pigmentation, but behavioural observations in animal models redirected attention toward sexual motivation. That shift made PT-141 one of the first melanocortin compounds investigated specifically for effects on desire rather than on skin colour.
Clinical development proceeded through two routes of administration. An intranasal formulation advanced first, but variable absorption and tolerability problems led to a switch to subcutaneous injection. The United States Food and Drug Administration approved the subcutaneous product in 2019 for hypoactive sexual desire disorder in premenopausal women. Marketing rights subsequently changed hands, and commercial availability has fluctuated since approval. Use in men, in postmenopausal women, and in combination with other agents remains outside the approved label.
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 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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H68N14O10 | Free base; the drug product is formulated as an acetate salt |
| Molar mass | About 1025 g/mol | Calculated for the free base |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| CAS Registry Number | 189691-06-3 | Common listing for the free base |
| Typical storage | -20 °C, desiccated, protected from light | Repeated freeze-thaw cycles are best avoided |
Bremelanotide is a synthetic cyclic heptapeptide developed under the research code PT-141. The code reflects its position in an internal compound series rather than a chemical classification, and the name bremelanotide was later adopted for regulatory filings. Structurally it belongs to the melanocortin peptide family and shares a core sequence motif with alpha-melanocyte-stimulating hormone. The compound is supplied as an acetate salt in aqueous solution for injection. In reference literature it is indexed under both the code and the generic name, a dual listing that can complicate database searches.
Early work on melanocortin analogs in the 1980s and 1990s produced peptides intended to influence pigmentation and appetite. One of these, melanotan II, was observed to affect sexual desire as an incidental finding in self-administration reports. Researchers then pursued analogs with altered receptor selectivity and improved handling characteristics, and PT-141 emerged from that program in the late 1990s. The development path moved from dermatology and metabolism toward a central nervous system application, a shift that shaped both trial designs and the eventual label.
Regulatory review of bremelanotide concluded in 2019 with approval in the United States for a defined indication in premenopausal women. The reviewed formulation is a single-use prefilled autoinjector given subcutaneously, and its label carries cardiovascular monitoring language tied to blood pressure changes recorded during trials. Availability outside the approving jurisdiction varies, and in several countries the compound remains unapproved or is handled as a prescription-only item. Compounded and research-grade material also circulates, and it differs from the reviewed product in purity, characterization, and chain of custody.
The compound emerged from a research programme examining melanocortin analogues for effects on skin pigmentation. During early human studies, participants reported spontaneous erections as an unexpected side effect, which redirected development toward sexual function rather than tanning. An intranasal formulation was investigated in clinical trials but did not reach market approval. A subcutaneous injectable version later completed the regulatory process, and the nasal route does not appear in approved labelling.
Approved use is narrow and jurisdiction-specific. In the United States, the injectable product is authorised for premenopausal women with acquired, generalised hypoactive sexual desire disorder, a diagnosis that requires documented distress. It is not approved for men, for postmenopausal women, or for use alongside hormonal contraceptives under the approved labelling. Outside regulated markets, the same peptide is frequently sold as a research chemical, where identity, purity, and sterility are not independently verified.
Bremelanotide is a synthetic cyclic heptapeptide developed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation and appetite signalling. Its structure contains seven amino acid residues joined by a lactam bridge that closes the ring between two side chains. The molecular formula is C50H68N14O10 and the nominal molecular mass is near 1025 daltons. Much of the early laboratory literature refers to the same molecule by the development code PT-141.
The sodium–potassium pump (sodium–potassium adenosine triphosphatase, also known as Na+/K+-ATPase, Na+/K+ pump, or sodium–potassium ATPase) is an enzyme (an electrogenic transmembrane ATPase) found in the cell membrane of all animal cells. It performs several functions in cell physiology. The Na+/K+-ATPase enzyme is an enzyme involved in active transport (i.e. it uses energy from ATP). For every ATP molecule that the pump uses, three sodium ions are exported and two potassium ions are imported. Thus, there is a net export of a single positive charge per pump cycle. The net effect is an extracellular concentration of sodium ions 5 times the intracellular concentration, and an intracellular concentration of potassium ions 30 times the extracellular concentration. The sodium–potassium pump was discovered in 1957 by the Danish scientist Jens Christian Skou, who was awarded a Nobel Prize for his work in 1997. Its discovery marked an important step forward in the understanding of how ions get into and out of cells, and its particular significance for excitable cells such as nerve cells, which depend on this pump to respond to stimuli and transmit impulses. All mammals have four different sodium pump sub-types, or isoforms. Each has unique properties and tissue expression patterns. Sodium–potassium ATPase belongs to the family of P-type ATPases.
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Docetaxel is used in the treatment of various cancers, including breast, lung, prostate, gastric, head and neck, and ovarian cancer. Clinical data have shown docetaxel to have cytotoxic activity against breast, colorectal, lung, ovarian, prostate, liver, renal, gastric, and head and neck cancers and melanoma. In hormone-refractory prostate cancer docetaxel improves life expectancy and overall life quality. The optimal dose scheduling of taxanes remains unconfirmed, but most studies find significant mortality benefit following either a three-week or a one-week administration schedule. While a 2010 article in Current Clinical Pharmacology states, "weekly administration has emerged as the optimal schedule," the official docetaxel package insert recommends administration every three weeks.
Joe: The Rise of Cobra Jenny Slate (2004), cast member, Saturday Night Live Anna Paquin* (2004), winner of the Academy Award for The Piano Rider Strong (2004), star of Boy Meets World Julia Jones (2005), actress in The Twilight Saga and Dexter: New Blood Julia Stiles (2005), star of Save the Last Dance and Mona Lisa Smile Kate McKinnon (2006), Emmy winning actress and comedian, Saturday Night Live Grace Parra (2006), actress, screenwriter, TV host Emmy Rossum* (2008), Golden Globe-nominated actress of The Phantom of the Opera and The Day After Tomorrow Hal Scardino (2008), child actor known for his role in The Indian in the Cupboard Jeremy Blackman (2009), appeared in Magnolia Max Minghella (2009), appeared in Syriana and Art School Confidential Spencer Treat Clark (2010), appeared in Gladiator, Mystic River, and Unbreakable Asher Grodman (2010), actor, Ghosts Sarah Steele (2011), actress, Spanglish Remy Zaken (2012), actress on Spring Awakening Jin Ha (2013), actor, Love Life, Devs Devyn Tyler (2013), actress, Clarice and Snowfall Gabby Beans (2014), actress, Tony Award for Best Actress in a Play nominee Kelsey Chow (2014), actress, Pair of Kings Cinta Laura (2014), actress and singer Sofia Vassilieva (2014), actress, Eloise at the Plaza, Eloise at Christmastime Marjana Chowdhury (2015), model, actress, philanthropist and beauty queen Hari Nef (2015), transgender model, actress, and writer; signed to IMG Models Ben Platt* (2016), actor and singer, Pitch Perfect, The Book of Mormon, Dear Evan Hansen, transferred to Columbia University School of General Studies Katie Chang* (2017), actress, The Bling Ring, A Birder's Guide to Everything Timothée Chalamet* (2017), Academy Award-nominated actor, Call Me by Your Name Sami Gayle (2018), actress, Blue Bloods, Candy Jar, Vampire Academy Kenny Ridwan (2021), actor, The Goldbergs Emily Robinson (2021), actress, The Orphans' Home Cycle, Eighth Grade Kiera Allen (2022), actress, Run Peyton Elizabeth Lee (2026), actress, Andi Mack Avantika Vandanapu (2027), actress, Mean Girls
Sources: en.wikipedia.org
In one interpretation of the film's plot, a scientific process supposedly extracts hydrogen from water, then burns the hydrogen to generate power, and leaves only water as a residue, essentially a chemical perpetual motion. The movie never clarifies how the hydrogen is extracted from the water, nor how water is still left over. The character Dr. Shannon makes contradictory statements in the combination of ideas mashed together: one time he says this is accomplished with a laser with millions of degrees, another time he says frequencies of sound and sonoluminescence. In one scene, the movie shows a bubbling container reminiscent of cold fusion electrolytic cells and another reference sustained fusion. A character in the film claims that a glass of water could power Chicago for weeks, but no clear explanation is ever given as to whether this is by simply burning hydrogen released by highly efficient means or through nuclear processes. The film's title is also misleading, since "chain reaction" is related to nuclear fission, not fusion. The film is based on the premise that free energy suppression is real. The main character is told that his discovery is too disruptive: energy would suddenly be cheap, oil would no longer be necessary, oil companies would go bankrupt, and such sudden economic changes would throw society into chaos.
== See also == Air-free technique – Chemistry laboratory technique Acidic oxide – Type of oxide, a.k.a. acid anhydride Base anhydride – Oxide of a chemical element from alkali- or alkaline earth metals Hydrate – Substance containing water or its constituent elements
Meyer even criticized Hutchinson publicly, prompting a meeting between the three men and team owner August Busch Jr., in which Hutchinson appealed to the owner to "Let me alone to do my job." "That thing with Mizell in Brooklyn, I just wanted to get him over a hump," Hutchinson later explained. Through July 27, Mizell had a 5.32 ERA, but his control started to improve in the middle of the year. Called on for a start on July 29, he held the Pirates to two hits in a 4–0 shutout victory. Thereafter, most of his appearances would be starts. With the second-place Cardinals trailing the NL-leading Milwaukee Braves on August 18, Mizell threw a four-hit shutout, helping the Cardinals sweep a doubleheader and remain in the pennant race. His ERA after July 27 was 2.54. In 33 games (21 starts), he had an 8–10 record, a 3.74 ERA, 87 strikeouts, and 51 walks in 149+1⁄3 innings. Over the 1957–58 offseason, Mizell practiced throwing with a steel ball. He arrived early to 1958 spring training, claiming to have lost 12 pounds from the previous spring. He had a 3–6 record entering June 21, but from that date through July 12, he won four straight games. On June 25, though he walked five batters, he allowed just three hits and one unearned run in a 3–1 victory over the Pirates. Then, on July 12, he threw a shutout in a 2–0 win over the Pirates. He had a pitching duel against Joe Nuxhall of Cincinnati in the first game of a doubleheader on September 1; Mizell prevailed 1–0, setting an NL record for most walks in a shutout with nine.
Sources: en.wikipedia.org
PT-141 is a research code for bremelanotide, a cyclic peptide that activates melanocortin receptors. It was developed for sexual dysfunction and later approved under a brand name as a subcutaneous injection. The same code is widely used by suppliers selling non-pharmaceutical material.
Both are synthetic melanocortin agonists and share a similar peptide backbone, but they are distinct molecules with different receptor profiles. Melanotan II was never approved as a medicine, whereas bremelanotide was. Findings about one compound should not be transferred to the other without direct evidence.
It is typically distributed as a lyophilized powder in sealed vials, sometimes with a separate solvent. Purity statements usually originate from the supplier rather than an independent laboratory. Storage recommendations vary between vendors, which makes comparison across sources difficult.
PT-141 is a laboratory code for bremelanotide, a synthetic peptide that activates melanocortin receptors. It has been developed both as an injectable pharmaceutical product and as a research chemical. The two contexts differ sharply in how identity, purity, and dosing are controlled.