The short version of peptide drug fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-08-29 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Research code | PT-141 | Used in early literature before the generic name became common |
| Generic name | Bremelanotide | International nonproprietary name |
| Peptide class | Cyclic heptapeptide | Seven residues joined by a lactam bridge |
| Primary receptor | MC4R | Lower affinity reported at MC1R, MC3R and MC5R |
| Route studied clinically | Subcutaneous injection | Intranasal route was abandoned after pressor effects |
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.
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.
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.
Compared with the related compound melanotan II, PT-141 shows markedly weaker activation of receptors tied to pigmentation. This difference stems from subtle structural variations that alter affinity distribution across receptor subtypes. Investigators propose that such selectivity produces a different side effect profile in specific applications. However, downstream consequences of prolonged receptor activation remain uncertain in the literature. Published studies do not fully agree on the duration of signaling pathway activity and the mechanisms of desensitization.
From a pharmacokinetic standpoint, the peptide is usually delivered by injection because oral bioavailability is very low; proteases in the digestive tract degrade it rapidly. After subcutaneous administration, plasma concentrations reach a peak within roughly one hour. Its elimination half-life is relatively short, with most reports placing it in the range of a few hours. Nasal formulations have also been examined, though absorption varies widely between individuals. Metabolism proceeds mainly through peptidase cleavage, and the resulting products are excreted by the kidneys.
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.
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.
The absorption rate constant Ka is a value used in pharmacokinetics to describe the rate at which a drug enters into the system. It is expressed in units of time−1. The Ka is related to the absorption half-life (t1/2a) per the following equation: Ka = ln(2) / t1/2a. Ka values can typically only be found in research articles. This is in contrast to parameters like bioavailability and elimination half-life, which can often be found in drug and pharmacology handbooks.
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== Other uses == Recurrent pyogenic cholangitis, a medical condition Red Paraguaya de Comunicación, a TV operator in Paraguay Rei Publicae Constituendae, part of the title of the members of the Second Triumvirate, appearing on Roman coins République populaire de Chine, República popular China, República popular da China, the French, Spanish and Portuguese names for the People's Republic of China RPC, a Panamanian national television network
In soil, microorganisms that reside in the rhizosphere (a zone that includes the root surface and the soil that adheres to the root after gentle shaking) carry out nitrogen fixation, converting nitrogen gas to nitrogenous compounds. This serves to provide an easily utilisable form of nitrogen for many plants, which cannot fix nitrogen themselves. Many other bacteria are found as symbionts in humans and other organisms. For example, the presence of over 1,000 bacterial species in the normal human gut flora of the intestines can contribute to gut immunity, synthesise vitamins, such as folic acid, vitamin K and biotin, convert sugars to lactic acid (see Lactobacillus), as well as fermenting complex undigestible carbohydrates. The presence of this gut flora also inhibits the growth of potentially pathogenic bacteria (usually through competitive exclusion) and these beneficial bacteria are consequently sold as probiotic dietary supplements. Nearly all animal life is dependent on bacteria for survival as only bacteria and some archaea possess the genes and enzymes necessary to synthesise vitamin B12, also known as cobalamin, and provide it through the food chain. Vitamin B12 is a water-soluble vitamin that is involved in the metabolism of every cell of the human body. It is a cofactor in DNA synthesis and in both fatty acid and amino acid metabolism. It is particularly important in the normal functioning of the nervous system via its role in the synthesis of myelin.
=== Two-dimensional === In this technique a square or rectangular paper is used. Here the sample is applied to one of the corners and development is performed at a right angle to the direction of the first run.
Sources: en.wikipedia.org
Fricasé is a traditional soup in Bolivian cuisine prepared with pork, pork ribs or chicken, hominy, chuño (a freeze-dried potato product) or potatoes, onion, garlic, salt, pepper and spices. It is sometimes consumed as a hangover food, as having a theoretical potential for easing or alleviating symptoms associated with the hangover. Fricasé is a common soup in Bolivia, and is often sold and consumed in the morning. It is a spicy soup that is typically prepared using large chunks of meat, and chuno potatoes are typically used in the Altiplano region of Bolivia. The aji pepper is sometimes used as an ingredient, and bread crumbs are sometimes used to thicken the soup.
=== Environmental and food safety tests === Paper-based microfluidic devices have several applications outside of the medical field. For example, paper-based biosensors have been used extensively in environmental monitoring. Two recent devices were developed for the detection of Salmonella and E. coli. The latter device was specifically used to detect E. coli in seven field water samples from Tucson, Arizona. Antibody-conjugated polystyrene particles were loaded in the middle of the microfluidic channel, after the sample inlet. Immunoagglutination occurs when samples containing Salmonella or E. coli, respectively, come into contact with these particles. The amount of immunoagglutination can be correlated with increased Mie scattering of light, which was detected with a specialized smartphone application under ambient light. Paper-based microfluidics has also been used to detect pesticides in food products, such as apple juice and milk. A recent design used piezoelectric inkjet printing to imprint paper with the enzyme acetylcholinesterase (AChE) and the substrate indophenyl acetate (IPA), and this paper-based microfluidic device was used to detect organophosphate pesticides (AChE inhibitors) via a decrease in blue-purple color. This device is distinguished by its use of bioactive paper instead of compartments with pre-stored reagents, and it was demonstrated to have good long-term stability, making it ideal for field use.
== Awards and honors == Raphael Katzen Award, Society for Industrial Microbiology, 2009. Fellow, Class of 2008, American Society for the Advancement of Science (AAAS). Featured profile, Nature Biotechnology, November 2007. Fellow, Society of Industrial Microbiology, 2003. College of Fellows, Class of 2001, American Institute of Medical and Biological Engineering (AIMBE).
=== Funding and revenue === In 2023, Breakthrough T1D raised $224 million; of this, 78% went toward programs including research funding, 15% was spent on fundraising, and 7% was spent on administrative costs. Cumulatively, Breakthrough T1D was funding approximately $568 million in T1D research projects worldwide in 2018.
Sources: en.wikipedia.org
The code designates bremelanotide, a cyclic heptapeptide melanocortin receptor agonist. It served as an internal research identifier before the compound entered formal clinical development. The code and the generic name refer to the same molecule.
MC4R is generally described as the principal target, based on binding affinity and functional assays. Activity at MC1R, MC3R and MC5R is reported as weaker. Receptor selectivity is one reason the compound was pursued for central rather than vascular effects.
Both are synthetic melanocortin analogues built on a similar cyclic peptide scaffold. Bremelanotide is described in the literature as a metabolite-derived analogue of melanotan II rather than the same substance. The two differ in terminal modifications, which affect half-life and receptor profile.
PT-141 was the internal development code assigned to bremelanotide during preclinical research. Reference sources sometimes index the peptide under the code rather than the generic name. The two terms describe the same molecule.