The short version of MC1R fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-08-31 and is reviewed periodically as new material appears.
Handling guidance for melanotan II follows general practice for small synthetic peptides rather than a product-specific monograph. Lyophilized powder is typically kept at minus twenty degrees Celsius or colder, protected from light and moisture, because warmth and humidity accelerate degradation. Once reconstituted, solutions are usually refrigerated and used within a short window, as hydrolysis and microbial growth both become concerns. Repeated freeze-thaw cycles are generally avoided. These conventions come from laboratory peptide chemistry and not from formal stability studies on this specific compound.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
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.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Dissolves readily in aqueous buffer |
| Typical storage temperature | -20 °C or below | Protect from light and moisture |
| Typical analytical method | Reversed-phase HPLC and LC-MS | Purity estimate plus mass confirmation |
| Unit of measure | Milligram per vial | Content varies by vendor |
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
Published research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
== Further reading == World Health Organization publications: Safety and nutritional adequacy of irradiated food, WHO, Geneva, 1994 High-dose irradiation: Wholesomeness of food irradiated with doses above 10 kGy, WHO, Geneva, 1999, Technical Report Series No. 890 Facts about Food Irradiation, A series of Fact Sheets from the International Consultative Group on Food Irradiation (ICGFI), 1999, IAEA, Vienna, Austria at the Wayback Machine (archived 2006-03-16) Diehl, J.F., Safety of irradiated foods, Marcel Dekker, N.Y., 1995 (2. ed.) Satin, M., Food irradiation, Technomic, Lancaster, 1996 (2. ed.) Urbain, W.M., Food irradiation, Academic Press, Orlando, 1986 Molins, R. (ed.), Food irradiation – Principles and applications, Wiley Interscience, N.Y., 2001 Sommers, C.H. and Fan, X. (eds.), Food Irradiation Research and Technology, Blackwell Publishing, Ames, IA, 2006 The Food That Would Last Forever : Understanding the Dangers of Food Irradiation, by Gary Gibbs, Garden City Park, N.Y. : Avery Pub. Group, c1993 anon., Food Irradiation: Available Research Indicates That Benefits Outweigh Risks, RCED-00-217, August 24, 2000, Government Accountability Office, United States General Accounting Office, Resources, Community, and Economic Development Division, Washington, D.C. 20548 "Food Irradiation" Farkas, József; Mohácsi-Farkas, Csilla (March 2011). "History and future of food irradiation". Trends in Food Science & Technology. 22 (2–3): 121–126. doi:10.1016/j.tifs.2010.04.002.
Carbonate is found frequently in geologic settings and constitutes an enormous carbon reservoir. Calcium carbonate occurs as aragonite, calcite and dolomite as significant constituents of the calcium cycle. The carbonate minerals form the rock types: limestone, chalk, marble, travertine, tufa, and others.
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=== Raid assessment === Another critical function of the CH operators was to estimate the number and type of aircraft in a raid. A gross level of the overall size could be determined by the strength of the return. But a much more accurate determination could be made by observing the "beat" rate of the composite echoes, the way they grew and diminished over time as they entered into different sections of the antenna reception pattern. To aid this, the operator could reduce the pulse length to 6 microseconds (from 20) with a push-button. This improved the range resolution, spreading the blip out on the display at the cost of lower returned energy. Raid assessment was largely an acquired skill and continued to improve with operator experience. In measured tests, experimenters found that acquired skill was so great that experienced operators could often pick out targets with returns less than the current signal-to-noise ratio. How this was accomplished was a great mystery at the time–the operators were spotting blips in static that were larger than the signal. It is currently believed this is a form of stochastic resonance.
Sources: en.wikipedia.org
Utilizing both the freeze-casting and salting-out processing techniques on poly(vinyl alcohol) hydrogels to induce hierarchical morphologies and anisotropic mechanical properties. Directional freezing of the hydrogels helps to align and coalesce the polymer chains, creating anisotropic array honeycomb tube-like structures while salting out the hydrogel yielded out a nano-fibril network on the surface of these honeycomb tube-like structures. While maintaining a water content of over 70%, these hydrogels' toughness values are well above those of water-free polymers such as polydimethylsiloxane (PDMS), Kevlar, and synthetic rubber. The values also surpass the toughness of natural tendon and spider silk.
The unit of account of the bitcoin system is the bitcoin. It is most commonly represented with the symbol ₿ designed in 2010 and the currency code BTC. However, the BTC code does not conform to ISO 4217 as BT is the country code of Bhutan, and ISO 4217 requires the first letter used in global commodities to be 'X'. XBT, a code that conforms to ISO 4217 though not officially part of it, is used by Bloomberg L.P. No uniform capitalization convention exists; some sources use Bitcoin, capitalized, to refer to the technology and network, and bitcoin, lowercase, for the unit of account. The Cambridge Advanced Learner's Dictionary and the Oxford Advanced Learner's Dictionary use the capitalized and lowercase variants without distinction. One bitcoin is divisible to eight decimal places. Units for smaller amounts of bitcoin are the millibitcoin (mBTC), equal to 1⁄1000 bitcoin, and the satoshi (sat), representing 1⁄100000000 (one hundred millionth) bitcoin, the smallest amount possible. 100,000 satoshis are one mBTC.
Christine Coates, Director, Coates Engineering (International Ltd). For services to Economic Development in North West England. Paulene Mary Collins. For services to Legal Education. Charles John Cooper, Principal Professional and Technology Officer, Ministry of Defence. Derek MacDonald Cooper. For services to Radio Broadcasting. Commodore George Richard Cooper, , Chief of Operations, Royal National Lifeboat Institution. For services to the RNLI. David Leonard Court. For services to Tourism in East Anglia. The Honourable Jurat John Alexander Gore Coutanche, lately Jurat, Royal Court of Jersey. For services to the community. Squadron Leader Robert Frederick Craig, Royal Air Force (Retd.), lately Grade 7, Ministry of Defence. Adrian Robert Currie, , Chief Fire Officer, Devon Fire and Rescue Service. For services to the Fire Service. Professor John Darby. For services to Community Relations. William Roch Davies, lately Director, Welsh Centre for International Affairs. For humanitarian services. Sally Dawn Ridley-Day. For political and public service. Peter Denley. For services to the Rehabilitation of Offenders. Brian Charles Dice. For services to British Waterways. James Dick, Director of Social Work Services, The Highland Council. For services to Social Work. Elizabeth Ann Dodsworth. For political service. Margaret Duddy. For political and public service. Andrew Nicholas Duff. For political service. Sister Mary Vincent Duggan. For services to Education. Helen Simpson Dunsmore. For services to Higher Education. Albert John Edwards, .
Sources: en.wikipedia.org
The lyophilized powder is generally held at minus twenty degrees Celsius or below, away from light and moisture. Reconstituted solutions are typically refrigerated and used quickly. These practices derive from general peptide handling rather than a formal stability study.
Reversed-phase liquid chromatography estimates purity, and mass spectrometry confirms molecular mass. Together they distinguish the intended peptide from truncated or modified forms. Sequence-level confirmation may use tandem mass spectrometry or amino acid analysis.
Because it is not made under pharmaceutical standards, purity and content can vary between vendors and batches. Independent testing has documented labeling discrepancies. A certificate of analysis from an accredited laboratory offers more assurance than a vendor's own claim.
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.