If you have been reading about MC1R and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-06-19. Numbers and descriptions here follow the published literature rather than marketing material.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
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.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms differ |
| Molecular weight | Approximately 1024 g/mol | Calculated for the free base |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and polar solvents | Poorly soluble in non-polar solvents |
| Typical storage | -20 degrees Celsius, dry, protected from light | Refers to the solid form |
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.
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.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
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.
=== Liquid chromatography === DESI can be coupled to ultra-fast liquid chromatography using an LC eluent splitting strategy. It is a strategy through a tiny orifice on an LC capillary tube. There is negligible dead volume and back pressure that allows for almost real time mass spectrometry detection with a fast elution and purification. This coupling can be used to ionize a wide range of molecules, from small organics to high mass proteins. This is different from ESI (electrospray ionization) in that it can be used to directly analyze salt-containing sample solutions without requiring “make-up” solvents/ acids to be doped into the sample. This set up allows for a high flow rate without splitting. The high resolution that is accomplished by reverse-phase HPLC can be combined with this procedure to produce high throughput screening of natural products as well. The incorporation of the electrochemistry component helps with ionization efficiency via the electrochemical conversion. This method is proved better than ESI in the fact that you don't have to separate the small potential that is applied to the cell from the potential on the spray in DESI. DESI also shows a better tolerance to inorganic salt electrolytes and you can use traditional solvents used in electrolysis.
Sharpe (1973), professor of English at Barnard College Stewart Sterk (1973), professor of law at the Benjamin N. Cardozo School of Law Richard Briffault (1974), professor of law at Columbia Law School David S. Katz (1974), professor of early modern European history at Tel Aviv University James R. Russell (1974), professor of Ancient Near Eastern studies at Harvard University Steven Simon (1974), Middle East expert and former executive director of International Institute for Strategic Studies-US; former senior director in the United States National Security Council Haruo Shirane (1974), professor of Japanese literature of Columbia University Jonathan Crary (1975), art critic, essayist, professor of art at Columbia University Robert S. Levine (1975), professor of American literature at University of Maryland, College Park Alexander J. Motyl (1975), professor of political science at Rutgers University David Albert (1976), professor of philosophy at Columbia University Louis Putterman (1976), professor of economics at Brown University Thomas Alan Schwartz (1976), professor of history at Vanderbilt University Barry Bergdoll (1977), chief curator of Architecture and Design at the Museum of Modern Art M. Gregg Bloche (1977), professor at Georgetown University Law Center Franco Mormando (1977), historian of Italy, professor at Boston College James S.
A wound is any disruption of or damage to living tissue, such as skin, mucous membranes, or organs. Wounds can either be the sudden result of direct trauma (mechanical, thermal, chemical), or can develop slowly over time due to underlying disease processes such as diabetes mellitus, venous/arterial insufficiency, or immunologic disease. Wounds can vary greatly in their appearance depending on wound location, injury mechanism, depth of injury, timing of onset (acute vs chronic), and wound sterility, among other factors. Treatment strategies for wounds will vary based on the classification of the wound, therefore it is essential that wounds be thoroughly evaluated by a healthcare professional for proper management. In normal physiology, all wounds will undergo a series of steps collectively known as the wound healing process, which include hemostasis, inflammation, proliferation, and tissue remodeling. Age, tissue oxygenation, stress, underlying medical conditions, and certain medications are just a few of the many factors known to affect the rate of wound healing.
Alistair Barkley who goes on the run with Eddie when they are framed for Alistair's murder and the destruction of his laboratory Fred Ward as FBI Agent Leon Ford, who leads the investigation to discover the cause of the destruction of the laboratory; initially focusing on Eddie and Lily, he soon suspects the involvement of government organizations Kevin Dunn as FBI Agent Doyle, Ford's assistant in the investigation who helps Ford track down Eddie, Lily, and later, C-Systems Brian Cox as Lyman Earl Collier, Chairman of C-Systems Research who is behind the conspiracy to keep the hydrogen power plant a secret Joanna Cassidy as Maggie McDermott, an old friend of Eddie's who lives in an observatory in Wisconsin, where Eddie and Lily escape to after a warrant is issued for their arrest Chelcie Ross as FBI Agent Ed Rafferty Nicholas Rudall as Dr. Alistair Barkley, head of the project to develop energy from the water who is later suffocated Tzi Ma as Lu Chen, Project Manager on the Hydrogen Project and Dr. Barkley's right-hand man; when Barkley is killed, Dr. Chen is kidnapped and forced to work at C-Systems Krzysztof Pieczyński as Lucasz Screbneski, the scientist on the original project who is secretly working for C-Systems Eddie Bo Smith Jr. and Danny Goldring as Yusef Reed and Clancy Butler, Collier's right hand men for C-Systems Margaret Travolta as Anita Fermi, Shannon's personal assistant. In addition, Michael Shannon and Neil Flynn make appearances as a van driver and a Wisconsin State Police Trooper, respectively.
Sources: en.wikipedia.org
=== Immediate-spin cross-matching === Immediate-spin cross-matching (ISCM) is an abbreviated form of cross-matching that is faster, but less sensitive; its primary use is to detect a mismatch between ABO blood types. It is an immediate test that involves combining the patient's serum and donor's red blood cells at room temperature, then centrifuging the sample and observing for agglutination or hemolysis. A lack of agglutination or hemolysis indicates a negative test reaction, or compatible match. ISCM is not appropriate in all circumstances; if the recipient's antibody screen is positive, or if they have had a positive antibody screen in the past, a full crossmatch is performed instead.
== Static and dynamic modes == In the field of surface analysis, it is usual to distinguish static SIMS and dynamic SIMS. Static SIMS is the process involved in surface atomic monolayer analysis, or surface molecular analysis, usually with a pulsed ion beam and a time-of-flight mass spectrometer, while dynamic SIMS is the process involved in bulk analysis, closely related to the sputtering process, using a DC primary ion beam and a magnetic sector or quadrupole mass spectrometer. Dynamic secondary-ion mass spectrometry (DSIMS) is a powerful tool for characterizing surfaces, including the elemental, molecular, and isotopic composition and can be used to study the structure of thin films, the composition of polymers, and the surface chemistry of catalysts. DSIMS was developed by John B. Fenn and Koichi Tanaka in the early 1980s. DSIMS is mainly used by the semiconductor industry.
In 1805, American inventor Oliver Evans described a closed vapor-compression refrigeration cycle for the production of ice by ether under vacuum. In 1820, the British scientist Michael Faraday liquefied ammonia and other gases by using high pressures and low temperatures, and in 1834, an American expatriate in Great Britain, Jacob Perkins, built the first working vapor-compression refrigeration system. It was a closed-cycle device that could operate continuously. A similar attempt was made in 1842, by American physician, John Gorrie, who built a working prototype, but it was a commercial failure. American engineer Alexander Twining took out a British patent in 1850 for a vapor compression system that used ether. The first practical vapor compression refrigeration system was built by James Harrison, a Scotsman. His 1856 patent was for a vapor compression system using ether, alcohol or ammonia. He built a mechanical ice-making machine in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Victoria, and his first commercial ice-making machine followed in 1854. Harrison also introduced commercial vapor-compression refrigeration to breweries and meat packing houses, and by 1861, a dozen of his systems were in operation. The first gas absorption refrigeration system (compressor-less and powered by a heat-source) was developed by Edward Toussaint of France in 1859 and patented in 1860. It used gaseous ammonia dissolved in water ("aqua ammonia").
Special Forces received a severe damage to its reputation when in July 1969 Colonel Robert Rheault, Commander of 5th Special Forces Group (Airborne), six subordinate military intelligence officers, attached to MACVSOG's Project GAMMA Operational Detachment B-57 including his headquarters staff intelligence officer, and a sergeant first class (SFC) were arrested for the murder of Thai Khac Chuyen, a suspected North Vietnamese double agent. It was suspected that Chuyen was providing the North Vietnamese Army information about Project GAMMA and the indigenous agents used by the 5th Special Forces Group. Thai Khac Chuyen's name was found on captured documents recovered from a MACV-SOG recon mission in Laos. An attempted cover-up was uncovered when the SFC became concerned that he might be a 'fall guy' and contacted the local Central Intelligence Agency (CIA) office chief. In September 1969 Secretary of the Army Stanley Resor announced that all charges would be dropped since the CIA, in the interests of national security, had refused to make its personnel available as witnesses; implying some sort of involvement.
=== Intramural and extramural research === In 2019, the NIH devoted 10% of its funding to research within its own facilities (intramural research), and gave >80% of its funding in research grants to extramural (outside) researchers. Of this extramural funding, a certain percentage (2.8% in 2014) must be granted to small businesses under the SBIR/STTR program. As of 2011, the extramural funding consisted of about 50,000 grants to more than 325,000 researchers at more than 3000 institutions. By 2018, this rate of granting remained reasonably steady, at 47,000 grants to 2,700 organizations. In FY 2010, the NIH spent US$10.7bn (not including temporary funding from the American Recovery and Reinvestment Act of 2009) on clinical research, US$7.4bn on genetics-related research, US$6.0bn on prevention research, US$5.8bn on cancer, and US$5.7bn on biotechnology.
Sources: en.wikipedia.org
== Exact mass == The exact mass of an isotopic species (more appropriately, the calculated exact mass) is obtained by summing the masses of the individual isotopes of the molecule. For example, the exact mass of water containing two hydrogen-1 (1H) and one oxygen-16 (16O) is 1.0078 + 1.0078 + 15.9949 = 18.0105 Da. The exact mass of heavy water, containing two hydrogen-2 (deuterium or 2H) and one oxygen-16 (16O) is 2.0141 + 2.0141 + 15.9949 = 20.0229 Da. When an exact mass value is given without specifying an isotopic species, it normally refers to the most abundant isotopic species (monoisotopic mass).
In 1820, Michael Faraday liquefied ammonia and other gases by using high pressures and low temperatures, and in 1834, Jacob Perkins built the first working vapor-compression refrigeration system in the world. It was a closed-cycle that could operate continuously, as he described in his patent, "I am enabled to use volatile fluids for the purpose of producing the cooling or freezing of fluids, and yet at the same time constantly condensing such volatile fluids, and bringing them again into operation without waste." His prototype system worked although it did not succeed commercially. In 1842, a similar attempt was made by physician John Gorrie, who built a working prototype, but it was a commercial failure. Like many of the medical experts during this time, Gorrie thought too much exposure to tropical heat led to mental and physical degeneration, as well as the spread of diseases such as malaria. He conceived the idea of using his refrigeration system to cool the air for comfort in homes and hospitals to prevent disease. American engineer Alexander Twining took out a British patent in 1850 for a vapour compression system that used ether. The first practical vapour-compression refrigeration system was built by the journalist James Harrison. His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. He built a mechanical ice-making machine in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Victoria, and his first commercial ice-making machine followed in 1854.
== Water activity == The water activity, aw, in a fish is defined as the ratio of the water vapour pressure in the flesh of the fish to the vapour pressure of pure water at the same temperature and pressure. It ranges between 0 and 1, and is a parameter that measures how available the water is in the flesh of the fish. Available water is necessary for the microbial and enzymatic reactions involved in spoilage. There are a number of techniques that have been or are used to tie up the available water or remove it by reducing the aw. Traditionally, techniques such as drying, salting and smoking have been used, and have been used for thousands of years. These techniques can be very simple, for example, by using solar drying. In more recent times, freeze-drying, water binding humectants, and fully automated equipment with temperature and humidity control have been added. Often a combination of these techniques is used.
This suggested that it was evolutionarily more difficult to increase the UV-sensitivity of the eyes of the males than to increase the UV-signals emitted by the females. Many insects use the ultraviolet wavelength emissions from celestial objects as references for flight navigation. A local ultraviolet emitter will normally disrupt the navigation process and will eventually attract the flying insect.
Sources: en.wikipedia.org
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.
Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.
Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.