This is a working overview of bremelanotide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-27 and is reviewed periodically as new material appears.
Outside the approved product, bremelanotide circulates as a research chemical sold by peptide vendors, often labelled PT-141. Such material is not manufactured under pharmaceutical quality standards, and independent testing has repeatedly found content that differs from the label. Analytical certificates supplied with a purchase are not strong evidence of purity because they are usually generated by the seller. Online discussion tends to blur the distinction between the approved drug and unregulated powder, which complicates interpretation of reported experiences.
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.
The lyophilised solid is relatively stable when kept dry, protected from light and held at reduced temperature, commonly minus 20 degrees Celsius or lower for long-term storage. In solution the peptide is more vulnerable: tryptophan oxidation, hydrolysis of the lactam bridge and aggregation all become relevant over time, and the rate depends on pH, buffer composition and concentration. Repeated freeze-thaw cycles are generally avoided because they promote aggregation. Aqueous working solutions are typically prepared fresh or split into single-use aliquots to limit degradation before analysis.
Published studies differ in design, population and endpoint definition, so results are not always directly comparable across reports. Some trials used patient-reported measures of desire and distress, while others tracked physiological or behavioural outcomes. Questions that remain open include the durability of effects beyond short follow-up periods, the frequency of transient blood pressure elevation observed after administration, and whether a subtype-selective analogue could separate central effects from pigmentation-related activity. These points are usually framed as unresolved rather than settled in review literature.
Routine characterisation of bremelanotide relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nm, where the peptide backbone absorbs. Mass spectrometry, typically in tandem mode with electrospray ionisation, confirms identity and supports quantification in biological matrices. Additional checks include amino acid analysis, peptide mapping after enzymatic digestion, and confirmation of the lactam bridge, since incomplete cyclisation produces a mass-shifted by-product. Purity values above 95 percent are common in reference-grade material, though reports vary in how strictly related substances are resolved from the parent peak.
| 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 |
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.
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.
Clinical programmes in this area have relied mainly on randomised, double-blind, placebo-controlled designs in premenopausal women. Primary endpoints usually combine a validated questionnaire covering desire domains with counts of satisfying sexual events and a separate measure of distress. Reported outcomes show statistically significant but modest average improvement over placebo, with wide individual variation. Adverse events such as nausea, flushing, and headache occur frequently and can limit tolerability. Whether short-term trial gains translate into lasting change for most users is an open question.
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.
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.
=== Deltas === Parts of the protein may have fixed three-dimensional structure without regular structures. They should not be confused with disordered or unfolded segments of proteins or random coil, an unfolded polypeptide chain lacking any fixed three-dimensional structure. These parts are frequently called "deltas" (Δ) because they connect β-sheets and α-helices. Deltas are usually located at protein surface, and therefore mutations of their residues are more easily tolerated. Having more substitutions, insertions, and deletions in a certain region of a sequence alignment maybe an indication of some delta. The positions of introns in genomic DNA may correlate with the locations of loops in the encoded protein . Deltas also tend to have charged and polar amino acids and are frequently a component of active sites.
In physics, a fluid is a liquid, gas, or other material that may continuously move and deform (flow) under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear force applied to them.
The now elderly McCormick reunites with the also elderly Helen and asks her to marry him; she happily accepts, proving that true love does indeed last forever. McCormick introduces Nat to Helen, and the film ends with the three joining hands and going for a seaside stroll together.
=== Regulation of extracellular amyloid β-protein === Reports of IDE localized to the cytosol and peroxisomes have raised concerns regarding how the protease could degrade endogenous Aβ. Several studies have detected insulin-degrading activity in the conditioned media of cultured cells, suggesting the permeability of the cell membrane and thus possible release of IDE from leaky cells. Qiu and colleagues revealed the presence of IDE in the extracellular media using antibodies to the enzyme. They also quantified levels of Aβ-degrading activity using elution from column chromatography. Correlating the presence of IDE and Aβ-degrading activity in the conditioning medium confirmed that leaky membranes are responsible for extracellular IDE activity. However, other reports have indicated that it is released via exosomes.
Sources: en.wikipedia.org
== External links == "Melanocortin Receptors". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Melanocortin+Receptors at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Calculated spatial position of melanocortin-4 receptor in the lipid bilayer, inactive state with antagonist and active state with agonist
This supplementation can offer a protective boost, enhancing the infant's ability to fend off infections and other health threats during the critical years when their immune system is still developing. The importance of this period underscores the need for targeted nutritional interventions to support overall immune health in young children.
=== Agricultural uses === It is used in agriculture for pest control of soil-borne pathogens such as Meloidogyne incognita or Helicotylenchus dihystera. It is also used as a mutagen for crop selection of plants such as rice, barley or oats.
MD simulation of the full satellite tobacco mosaic virus (STMV) (2006, Size: 1 million atoms, Simulation time: 50 ns, program: NAMD) This virus is a small, icosahedral plant virus that worsens the symptoms of infection by Tobacco Mosaic Virus (TMV). Molecular dynamics simulations were used to probe the mechanisms of viral assembly. The entire STMV particle consists of 60 identical copies of one protein that make up the viral capsid (coating), and a 1063 nucleotide single stranded RNA genome. One key finding is that the capsid is very unstable when there is no RNA inside. The simulation would take one 2006 desktop computer around 35 years to complete. It was thus done in many processors in parallel with continuous communication between them. Folding simulations of the Villin Headpiece in all-atom detail (2006, Size: 20,000 atoms; Simulation time: 500 μs= 500,000 ns, Program: Folding@home) This simulation was run in 200,000 CPU's of participating personal computers around the world. These computers had the Folding@home program installed, a large-scale distributed computing effort coordinated by Vijay Pande at Stanford University. The kinetic properties of the Villin Headpiece protein were probed by using many independent, short trajectories run by CPU's without continuous real-time communication. One method employed was the Pfold value analysis, which measures the probability of folding before unfolding of a specific starting conformation. Pfold gives information about transition state structures and an ordering of conformations along the folding pathway.
== Military == The Armed Forces of Serbia and Montenegro (Serbian: Војска Србије и Црне Горе/Vojska Srbije i Crne Gore, ВСЦГ/VSCG), previously known as Army of Yugoslavia (Serbian: Војска Југославије/Vojska Jugoslavije, ВЈ/VJ) included ground forces with internal and border troops, naval forces, air and air defense forces, and civil defense. It was established from the remnants of the Yugoslav People's Army (JNA), the military of the SFR Yugoslavia. Several Bosnian Serb units of the VJ were transferred over to the Republika Srpska, during the course of the Bosnian War, leaving only units directly from Serbia and Montenegro in the armed forces. The VJ saw military action during the Yugoslav Wars, including the Siege of Dubrovnik, as well as the Kosovo War, and played combat roles during ethnic insurgencies. Following the Kosovo War, the VJ was forced to evacuate Kosovo, and in 2003 it was renamed the ''Armed Forces of Serbia and Montenegro.'' Following the dissolution of the Union between Serbia and Montenegro, units from each army were assigned to the independent republics of Serbia and Montenegro, as recruitment in the army was on a local, rather than Federal, level. Montenegro inherited the small navy of the FR Yugoslavia, due to Serbia being landlocked.
Sources: en.wikipedia.org
==== Herbal ==== The American College of Rheumatology states that no herbal medicines have health claims supported by high-quality evidence and thus they do not recommend their use. There is no scientific basis to suggest that herbal supplements advertised as "natural" are safer for use than conventional medications as both are chemicals. Herbal medications, although labelled "natural", may be toxic or fatal if consumed. Due to the false belief that herbal supplements are always safe, there is sometimes a hesitancy to report their use which may increase the risk of adverse reactions.
==== Dendrotoxins ==== Dendrotoxins inhibit neurotransmissions by blocking the exchange of positive and negative ions across the neuronal membrane lead to no nerve impulse, thereby paralyzing the nerves. Snake example: mambas
M + Ph2CO → M+Ph2CO•− Generally sodium is used as the alkali metal. Sodium-benzophenone ketyl is used in the purification of organic solvents, particularly ethers, because it reacts with water and oxygen to give non-volatile products. Adsorbents such as alumina, silica gel, and especially molecular sieves are superior and far safer. The sodium-benzophenone method is common since it gives a visual indication that water, oxygen, and peroxides are absent from the solvent. Large scale purification may be more economical using devices which utilize adsorbents such as the aforementioned alumina or molecular sieves. The ketyl is soluble in the organic solvent being dried, which leads to faster purification. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. When excess alkali metal is present a second reduction may occur. The twice reduced specie presents as a clear red (extra-dry) solution. A color transformation from deep opaque blue (pure once-reduced benzophenone) to red with stages of opaque purple, indicate a mix of anion and bisanion.
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== FGE-mechanism of cysteine-formylglycine conversion == The catalytic mechanism of FGE is well studied. A multistep redox reaction with a covalent enzyme: substrate intermediate is proposed. The role of the cysteine residue for the occurring conversion was studied by mutating the cysteine to alanine. No conversion was found using mass spectrometry when the mutated peptide tag was used. The mechanism shows the important role of the redox active thiol group of cysteine in the formation of f(Gly), as seen in Fig. 2. The key step of the catalytic cycle is the monooxidation of the cysteine residue of the enzyme, forming a reactive sulfenic acid intermediate. Subsequently, the hydroxyl group is transferred to the cysteine of the substrate and after hetero-analogous β-elimination of H2O, a thioaldehyde is formed. This compound is very reactive and easily hydrolyzed, releasing the aldehyde and a molecule of H2S,
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.
The peptide is polar and charged, and reversed-phase chromatography with acidic mobile phases resolves it well from related substances. Ultraviolet detection near 214 nm gives adequate sensitivity without derivatisation.