melanocortin receptor comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
It is a member of the family of heme-containing peroxidases. Heme peroxidases catalyse the hydrogen peroxide-dependent oxidation of a wide range of different, usually organic, substrates in biology. This enzyme belongs to the family of oxidoreductases, specifically those acting on a peroxide as acceptor (peroxidases). The systematic name of this enzyme class is L-ascorbate:hydrogen-peroxide oxidoreductase. Other names in common use include L-ascorbic acid peroxidase, L-ascorbic acid-specific peroxidase, ascorbate peroxidase, and ascorbic acid peroxidase. This enzyme participates in the ascorbate and aldarate metabolism. APXs are important in cellular antioxidant networks in photosynthetic organisms; they are the primary component of the ascorbate-glutathione cycle and are important for peroxide scavenging and redox signaling.
There are two independent families of glutamic proteases (G1 and G2), and have a limited distribution. They were originally thought to be limited to filamentous fungi mainly in the Ascomycota phylum. Subsequently, however, glutamic proteases have been identified in bacteria and archaea. A glutamic protease from a plant virus (strawberry mottle virus) has also been identified. The first superfamily of glutamic proteases was identified in the fungi Scytalidium lignicola and Aspergillus niger var. macrosporus, from which scytalidoglutamic peptidase (eqolisin) and aspergilloglutamic peptidase are derived respectively. These two proteases contain active site Glu and Gln residues and are grouped under MEROPS family G1. A convergently evolved glutamic peptidase, the pre-neck appendage protein (bacteriophage phi-29), uses a Glu and Asp dyad at the active site, and is classified as MEROPS family G2.
It's good to be with friends and family as we struggle to deal with this immense loss ... and try to celebrate this immense life. We are looking for all the usual things: comfort, purpose, answers, something to hold on to, a way to let him go in peace. Mostly, we are feeling heartbroken over the death of our beautiful friend. He was a sweet man with a keen sense of humor and a deep sense of humanity. He was an amazing musician, an inspiration, and a comfort to so many. He made great music and gifted it to the world. We are proud to have known him, to be his friend, and to create music with him. For the past decade, Layne struggled greatly—we can only hope that he has at last found some peace. We love you, Layne. Dearly. And we will miss you ... endlessly. In 2010, in an interview on VH1's Celebrity Rehab, former Alice in Chains bass player Mike Starr said that he was the last person to see Staley alive and had spent time with him the day before his death, April 4 (Starr's birthday). Starr claimed that Staley was very sick but would not call 9-1-1. They briefly argued, which ended with Starr storming out. Starr stated that Staley called after him as he left and said: "Not like this, don't leave like this." Starr expressed regret for not calling 9-1-1, and stated that Staley had threatened to sever their friendship if he did. Starr also regretted being high on benzodiazepines that night and having walked out of the door. Staley's mother was insistent that neither she nor anyone in her family blamed Starr for Staley's death, telling Starr: "Layne would forgive you.
== Universities == According to the 2020 QS World University Rankings, Chulalongkorn University (CU) was ranked 247th in the world and earned the top ranking in Thailand for the seventh consecutive year. Also ranked were Mahidol University (314th), and Chiang Mai University and Thammasat University (both in the 601–650 tranche), and four other Thai universities in the 801–1,000 tranche. The Times Higher Education Asia University Rankings 2018 ranked Mahidol University as the top Thai institution. It ranked 97 of some 350 universities (1=best; 350=lowest). King Mongkut's University of Technology Thonburi was ranked 116, Chulalongkorn University 164, and Suranaree University of Technology 168. Thailand had no other universities in the top 200. Chulalongkorn University was ranked number one in Thailand and 45th in Asia in 2016. Mahidol University was ranked the top Thai university among the top 200 Asian (including Middle Eastern) universities in 2016 by Times Higher Education Asia University Rankings 2016.
Perforin's role in protecting the body against lymphoma was emphasized when scientists discovered that p53 did not have as big of a role in lymphoma surveillance as its counterpart perforin. Perforin and granzymes have been found to have a directly related ability to protect the body against the formation of different kinds of lymphomas.
Sources: en.wikipedia.org
Building automation, access control, smart energy — DASH7's signal propagation characteristics allow it to penetrate walls, windows, doors, and other substances that serve as impediments to other technologies operating at 2.45 GHz, for example. For smart energy and building automation applications, DASH7 networks can be deployed with far less infrastructure than competing technologies and at far lower total cost of ownership. Location-based services — DASH7 is being used today for developing new location-based services using a range of DASH7-enabled devices, including smartcards, keyfobs, tickets, watches and other conventional products that can take advantage of the unique small footprint, low power, long range, and low cost of DASH7 relative to less practical and high-power wireless technologies like Wi-Fi or Bluetooth. Using DASH7, users can "check in" to venues in ways not practical with current check-in technologies like GPS, that are power-intensive and fail indoors and in urban environments. Location-based services like Foursquare, Novitaz, or Facebook can exploit this capability in DASH7 and award loyalty points, allow users to view the Facebook or X, formally known as Twitter, addresses of those walking past, and more. Mobile advertising — DASH7 is being developed for "smart" billboards and kiosks, likewise "smart" posters that can be read from many meters (or even kilometers) away, creating new opportunities for both tracking the effectiveness of advertising expenditures, but also creating new e-commerce opportunities.
complete encasement in concrete square column. wrapping the i-beam in a thin layer of metal lath and then covering it with gypsum plaster. This method is effective because gypsum plaster contains water crystals that are heat resistant. applying multiple layers of gypsum board around the i-beam. applying spray-on fireproofing around the i-beam. Also called spray-applied fire-resistive materials (SFRM) using air pressured spray gun, which can be made from gypsum plaster, mineral fibers mixed with inorganic binder or a cementitious formula using magnesium oxychloride cement. enclosing the i-beam in sheet metal and fill with loose insulation. hollow columns filled with liquid water or antifreeze. When part of the column is exposed to fire, the heat is dissipated throughout by the convection property of the liquid. encasing the i-beam in rigid concrete slab. a layer of suspended plaster ceiling isolating the i-beam
== Origins == In 1927, Sakel, who had recently qualified as a medical doctor in Vienna and was working in a psychiatric clinic in Berlin, began to use low (sub-coma) doses of insulin to treat drug addicts and psychotics, and when one of the patients experienced improved mental clarity after having slipped into an accidental coma, Sakel reasoned the treatment might work for mentally ill patients. Having returned to Vienna, he treated schizophrenic patients with larger doses of insulin in order to deliberately produce coma and sometimes convulsions. Sakel made his results public in 1933, and his methods were soon taken up by other psychiatrists. Joseph Wortis, after seeing Sakel practice it in 1935, introduced it to the US. British psychiatrists from the Board of Control visited Vienna in 1935 and 1936, and by 1938, 31 hospitals in England and Wales had insulin treatment units. In 1936, Sakel moved to New York and promoted the use of insulin coma treatment in US psychiatric hospitals. By the late 1940s, the majority of psychiatric hospitals in the US were using insulin coma treatment.
(WINNER) The contestant won the whole competition. ‡ The contestant won the Pre-Heat challenge. (WIN) The contestant won the Main Heat challenge. (HIGH) The contestant had one of the best dishes for that week. (IN) The contestant performed well enough to move on to the next week. (LOW) The contestant had one of the bottom dishes for that week, but was not eliminated. (OUT) The contestant was eliminated for worst dish.
Sources: en.wikipedia.org
== Therapeutic uses of neohormones == Relaxin has been shown to repair and reverse the symptoms associated with scleroderma (an autoimmune condition affecting connective tissues, blood vessels and internal organs) and fibrosis (thickening, hardening or build up of scar tissue). It also aids in the formation of new blood vessels (angiogenesis). This is also beneficial in wound management and healing. Other potential targets include the use of relaxin within human reproduction, such as in the preparation of the cervix for labour and birth and also as a drug target for breast cancer treatment although much more research is required in this area. Oxytocin is important for many different biological processes including social, maternal and sexual behaviours, pregnancy, milk production, and ejaculation. Agonists and antagonists of oxytocin – development of drugs that can utilise the receptor binding activity of oxytocin is an important therapeutic target as this could be applied to a range of conditions. Oxytocin plays a role in cell proliferation and differentiation in different ways depending on where it is in the body. Understanding the underlying pathways for different localities could help with development of cancer therapies.
Currently, very few methods are used to synthesize (S)-dapoxetine. This novel approach consists of only six steps in which three main steps are shown above. The initial reactant is trans-cinnamyl alcohol, which is commercially available. Sharpless asymmetric epoxidation and Mitsunobu reaction have been used to produce expected (S)-dapoxetine. The overall yield is 35%. This method is considered a good choice compared to the known methods due to high yield and easily obtainable reactants.
=== Metabolism === 2-Coumarate reductase is an enzyme that converts o-coumaric acid to melilotic acid using reduced nicotinamide adenine dinucleotide (NADH). This enzyme participates in phenylalanine metabolism.
When making transmission measurements, the spectrophotometer quantitatively compares the fraction of light that passes through a reference solution and a test solution, then electronically compares the intensities of the two signals and computes the percentage of transmission of the sample compared to the reference standard. For reflectance measurements, the spectrophotometer quantitatively compares the fraction of light that reflects from the reference and test samples. Light from the source lamp is passed through a monochromator, which diffracts the light into a "rainbow" of wavelengths through a rotating prism and outputs narrow bandwidths of this diffracted spectrum through a mechanical slit on the output side of the monochromator. These bandwidths are transmitted through the test sample. Then the photon flux density (watts per meter squared usually) of the transmitted or reflected light is measured with a photodiode, CCD or other light sensor. The transmittance or reflectance value for each wavelength of the test sample is then compared with the transmission or reflectance values from the reference sample. Most instruments will apply a logarithmic function to the linear transmittance ratio to calculate the 'absorbency' of the sample, a value which is proportional to the 'concentration' of the chemical being measured. In short, the sequence of events in a scanning spectrophotometer is as follows:
== NAAS selected bibliography == 1955 Nuclear magnetic resonance saturation and rotary saturation in solids. Physical Review 98(6):1787–1809. 1959 With A. G. Anderson. Nuclear spin-lattice relaxation in metals. Physical Review 116(3):583–591. 1963. Pure nuclear electric quadrupole resonance in impure copper. Physical Review 130(2):589–595. 1963 With M. Eisenstadt. Nuclear spin relaxation by translational diffusion in solids. Physical Review 132(2):635–643. Pure nuclear electric quadrupole resonance in impure copper. Physical Review 130(2):589–595. 1965 The theory of relaxation processes. In Advances in Magnetic and Optical Resonance, pp. 1–32. 1967 Local-field mapping in mixed-state superconducting vanadium by nuclear magnetic resonance. Physical Review 162(2):367–374. 1969 Nuclear spin thermodynamics in the rotating frame. Science 164(3883):1015–1023. 1970 With R. K. Gupta. Double nuclear magnetic resonance observation of electron exchange between ferri- and ferrocytochrome c. Science 169(3951):1204–1206. 1971 With H. E. Bleich. Higher resolution NMR of rare spins in solids [1]. The Journal of Chemical Physics 55(11):5405–5406. 1971 With R. K. Gupta. Pulsed Fourier transform nuclear magnetic resonance spectrometer. In Advances in Magnetic and Optical Resonance, pp. 81–115. 1973 With A. Z. Genack. Nuclear spin diffusion and its thermodynamic quenching in the field gradients of a Type-II superconductor. Physical Review Letters 31(19):1204–1207. 1975 With S. D. Kunz and E. K. Ralph. Dynamic range in Fourier transform proton magnetic resonance.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
Laboratory confirmation typically combines retention time matching on a chromatographic system with mass measurement. A reference standard of known identity is needed for a meaningful comparison. Sequence-level techniques can add further confirmation.