A practical reference on alpha-MSH analogue: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-30. Anything still debated is marked as such rather than presented as settled.
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.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
| 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 |
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
=== Applications in semiconductor industry === UPW is used extensively in the semiconductor industry where the highest grade of purity is required. The use of UPW varies; it may be used to rinse the wafer after application of chemicals, to dilute the chemicals themselves, in optics systems for immersion photolithography, or as make-up to cooling fluid in some critical applications. UPW is even sometimes used as a humidification source for the cleanroom environment. The primary, and most critical, application of UPW is in wafer cleaning in and after wet etching step during the FEOL stage. Impurities which can cause product contamination or impact process efficiency (e.g. etch rate) must be removed from the water during cleaning and etching stage. In chemical-mechanical polishing processes, water is used in addition to reagents and abrasive particles. As of 2002 1-2 parts of contaminating molecules per one million of water ones was considered to be an "ultrapure water" (e.g. semiconductor grade).
== Translocation and peptide loading == The peptide translocation from the cytosol into the lumen of the ER is accomplished by the transporter associated with antigen processing (TAP). TAP is a member of the ABC transporter family and is a heterodimeric multimembrane-spanning polypeptide consisting of TAP1 and TAP2. The two subunits form a peptide binding site and two ATP binding sites that face the cytosol. TAP binds peptides on the cytoplasmic side and translocates them under ATP consumption into the lumen of the ER. The MHC class I molecule is then, in turn, loaded with peptides in the lumen of the ER. The peptide-loading process involves several other molecules that form a large multimeric complex called the peptide-loading complex consisting of TAP, tapasin, calreticulin, calnexin, and Erp57 (PDIA3). Calnexin acts to stabilize the class I MHC α chains prior to β2m binding. Following complete assembly of the MHC molecule, calnexin dissociates. The MHC molecule lacking a bound peptide is inherently unstable and requires the binding of the chaperones calreticulin and Erp57. Additionally, tapasin binds to the MHC molecule and serves to link it to the TAP proteins and facilitates the selection of peptide in an iterative process called peptide editing, thus facilitating enhanced peptide loading and colocalization. Once the peptide is loaded onto the MHC class I molecule, the complex dissociates and it leaves the ER through the secretory pathway to reach the cell surface.
Testing for the presence of residual solvents in Active Pharmaceutical Ingredients (APIs) is critical for patient safety and commonly follows United States Pharmacopeia (USP) Method <467> guidelines, or more broadly, International Council for Harmonisation (ICH) Guideline Q3C(R6). The gas chromatography (GC) runtime suggested by USP Method 467 is approximately 60 min. A generic method for residual solvent analysis by GC-MS describes conditions that include a runtime of approximately 30 minutes. A GC-VUV and static headspace method was developed using a chromatographic compression strategy that resulted in a GC runtime of 8 minutes. The GC-VUV method uses a flow rate of 4 mL/min and an oven ramp of 35 °C (held for 1 min), followed by an increase to 245 °C at a rate of 30 °C/min. Figure 5 compares the results when the general conditions of the GC-MS method were followed against the GC-VUV method run with Class 2 residual solvents. Tetralin eluted at approximately 35 minutes using the GC-MS method conditions, whereas the analyte had a retention time of less than 7 minutes when the GC-VUV method was applied. The co-elution of m- and p-xylene occurred in both GC-MS and GC-VUV method runs. VUV software matched the analyte absorbance of both isomers with VUV library spectra (Figure 2) to deconvolve the overlapping signals as displayed in Figure 6. Goodness of fit information ensures that the correct compound assignment takes place during the post-run data analysis.
Mummies have been discovered in Korea that have been dated to around the 15th to 19th centuries, during the Joseon period. This is thought to be because of the rise of Neo-Confucianism in Korea, which prescribed certain burial practices that created conditions favorable to mummification. However, this mummification was likely unintentional, and even culturally seen as ominous and undesirable. Mummification likely occurred due to a number of factors. One such factor was the airtight seal (especially as the Korean climate is unfavorable to mummification) around the bodies, which was achieved using a mix of lime, clay, and sand. Recreations of the sealing process found that chemical reactions with the lime possibly caused a high and prolonged release of heat, which killed bacteria in the bodies. In addition, a large amount of clothing was usually placed inside tombs, which led to a shortage of oxygen inside. Mummies buried using the lime mixture sealing technique reportedly have especially excellently preserved soft skin and hair, which has enabled medical and genetic studies to be performed. Insights have been offered into the lifestyles and pathologies of Korean people during this period. Specific diseases for each individual have been identified.
=== Follow-up and equity considerations === Ongoing follow-up includes monitoring waist circumference, body weight, blood pressure, lipids, and fasting glucose or HbA1c. Recent guidance emphasises equitable care through culturally appropriate counselling, affordable medication access, and community-based support.
Sources: en.wikipedia.org
==== Heritage Guernsey ==== On 2 July Essendon unveiled their Heritage Guernsey. It feature all the names of past premiership players in the background along with the name and signature of club legend John Colman on the breast. Under the signature include the traditional Essendon Football Club motto 'suaviter in modo, fortiter in re' which dates back to the 1870s and translates as 'gentle in manner, resolute in deed.' The most notable change to the guernsey was the removal of the black background to comply with AFL rules requiring each club to provide a clash guernsey. The new Heritage guernsey made its debut during the Round 15 game between St Kilda and Essendon. This marked the end of a 114-year-long tradition as the first time the Essendon Football Club would play an AFL/VFL game without wearing its famous black and red stripe guernsey.
== Process == The first step of the PEGylation is the suitable functionalization of the PEG polymer at one or both ends. PEGs that are activated at each end with the same reactive moiety are known as "homobifunctional", whereas if the functional groups present are different, then the PEG derivative is referred as "heterobifunctional" or "heterofunctional". The chemically active or activated derivatives of the PEG polymer are prepared to attach the PEG to the desired molecule. The overall PEGylation processes used to date for protein conjugation can be broadly classified into two types, namely a solution phase batch process and an on-column fed-batch process. The simple and commonly adopted batch process involves the mixing of reagents together in a suitable buffer solution, preferably at a temperature between 4 and 6 °C, followed by the separation and purification of the desired product using a suitable technique based on its physicochemical properties, including size exclusion chromatography (SEC), ion exchange chromatography (IEX), hydrophobic interaction chromatography (HIC) and membranes or aqueous two-phase systems (ATPS). The choice of the suitable functional group for the PEG derivative is based on the type of available reactive group on the molecule that will be coupled to the PEG. For proteins, typical reactive amino acids include lysine, cysteine, histidine, arginine, aspartic acid, glutamic acid, serine, threonine and tyrosine.
== History == In 1891 G. Merling obtained a water-soluble bromine-containing compound from the reaction of cycloheptatriene and bromine. Unlike most alkyl bromides, this compound, later named tropylium bromide, is water-soluble but insoluble in many organic solvents. It is purified by crystallization from hot ethanol. Reaction with aqueous silver nitrate immediately gave silver bromide, indicating labile bromide. Tropylium bromide was deduced to be a salt, C7H+7Br−, by Doering and Knox in 1954 by analysis of its infrared and ultraviolet spectra. The ionic structures of tropylium perchlorate (C7H+7ClO−4) and tropylium iodide (C7H+7I−) have been confirmed by X-ray crystallography. The bond length of the carbon-carbon bonds is longer (147 pm) than those of benzene (140 pm) but still shorter than those of a typical single-bonded species like ethane (154 pm).
In April 1978, the communist People's Democratic Party of Afghanistan (PDPA) seized power in Afghanistan in the Saur Revolution. Within months, opponents of the communist regime launched an uprising in eastern Afghanistan that quickly expanded into a civil war waged by guerrilla mujahideen against government forces countrywide. The Islamic Unity of Afghanistan Mujahideen insurgents received military training and weapons in neighboring Pakistan and China, while the Soviet Union sent thousands of military advisers to support the PDPA government. Meanwhile, increasing friction between the competing factions of the PDPA—the dominant Khalq and the more moderate Parcham—resulted in the dismissal of Parchami cabinet members and the arrest of Parchami military officers under the pretext of a Parchami coup. By mid-1979, the United States had started a covert program to assist the mujahideen. In September 1979, Khalqist President Nur Muhammad Taraki was assassinated in a coup within the PDPA orchestrated by fellow Khalq member Hafizullah Amin, who assumed the presidency. Distrusted by the Soviets, Amin was assassinated by Soviet special forces during Operation Storm-333 in December 1979. Afghan forces suffered losses during the Soviet operation; 30 Afghan palace guards and over 300 army guards were killed while another 150 were captured. In the aftermath of the operation, a total of 1,700 Afghan soldiers who surrendered to Soviet forces were taken as prisoners, and the Soviets installed Babrak Karmal, the leader of the PDPA's Parcham faction, as Amin's successor.
Sources: en.wikipedia.org
The Schengen rules do not require any other procedures; thus, the Schengen states are free to regulate further details on the content of the registration forms, and identity documents which are to be produced, and may also require the persons exempted from registration by Schengen laws to be registered. A Schengen state is also permitted to reinstate border controls with another Schengen country for a short period where there is a serious threat to that state's "public policy or internal security" or when the "control of an external border is no longer ensured due to exceptional circumstances". When such risks arise out of foreseeable events, the state in question must notify the European Commission in advance and consult with other Schengen states. Since the implementation of the Schengen Agreement, this provision has been invoked frequently by member states, especially in response to the European migrant crisis.
Indoors ozone (O3) is produced by certain high-voltage electric devices (such as air ionizers), and as a by-product of other types of pollution. It appears in lower concentrations indoors than outdoors, usually at 0.2–0.7 of the outdoor concentration. Typically, most ozone is lost to surface reactions indoors, rather than to reactions in air, due to the large surface to volume ratios found indoors. Outdoor air used for ventilation may have sufficient ozone to react with common indoor pollutants as well as skin oils and other common indoor air chemicals or surfaces. Particular concern is warranted when using "green" cleaning products based on citrus or terpene extracts, because these chemicals react rapidly with ozone to form toxic and irritating chemicals as well as fine and ultrafine particles. Ventilation with outdoor air containing elevated ozone concentrations may complicate remediation attempts. The WHO standard for ozone concentration is 60 μg/m3 for long-term exposure and 100 μg/m3 as the maximum average over an 8-hour period. The EPA standard for ozone concentration is 0.07 ppm average over an 8-hour period.
The matrix (4) is often referred to as the transfer matrix. It is used to evaluate whether an ion will have stable motion. If the absolute value of the trace of this matrix is less than 2 the ion is said to have stable motion. Stable motion simply means that the secular oscillation of the ion has a maximum displacement. When the absolute value of the trace is greater than 2 ion motion is not stable and the displacement of the ion increases with each secular oscillation. Ion trajectories in a linear or 3D DIT as well as in a digital mass filter, may also be calculated using a similar procedure. Unlike stability calculation it is advantageous for the purpose of resolution and accuracy to represent each period of the waveform with an adequate number of constant voltage steps. The trajectory for the constant potential step,
=== Differential diagnosis === Symptoms of early scabies infestation mirror other skin diseases, including dermatitis, syphilis, erythema multiforme, various urticaria-related syndromes, allergic reactions, ringworm-related diseases, and other ectoparasites such as lice and fleas.
Adenomatous polyposis coli protein 2 is a protein that in humans is encoded by the APC2 gene. This is a dual-functional protein which is especially prevalant in the developing brain, and involved in cell signaling (specifically Wnt signaling) and stabilizing the cytoskeleton. Frizzled receptors are a type of cell receptor involved in a variety of functions including embryonic development and cell proliferation. These receptors trigger a cascade of reactions called the Wnt signaling pathway that eventually leads to interaction with the DNA via the protein beta-catenin, which affects which proteins get produced by the cell. The APC2 protein promotes the formation of a protein complex which is involved in breaking down the protein beta-catenin. The APC2 protein stabilizes microtubules, which are part of the cell cytoskeleton. It may also be involved in the regulation of actin fibers my means of GTPase activation (specifically the Rho family).
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.
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.