If you have been reading about Melanotan II 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.
Last reviewed on 2026-06-16. 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.
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 II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
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.
| 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 |
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.
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.
== Pathology == It has been suggested that these cell rests are the histogenetic origins of Brenner tumors, due to the histological similarity of the epithelium of Walthard cell rests and Brenner tumors to the urothelium of the lower urinary tract. Also, it has been proposed that Brenner tumors and Walthard cell rests signify urothelial differentiation within the female genital tract.
As an example of varying pressures, a finger can be pressed against a wall without making any lasting impression; however, the same finger pushing a thumbtack can easily damage the wall. Although the force applied to the surface is the same, the thumbtack applies more pressure because the point concentrates that force into a smaller area. Pressure is transmitted to solid boundaries or across arbitrary sections of fluid normal to these boundaries or sections at every point. Unlike stress, pressure is defined as a scalar quantity. The negative gradient of pressure is called the force density. Another example is a knife. If the flat edge is used, force is distributed over a larger surface area resulting in less pressure, and it will not cut. Whereas using the sharp edge, which has less surface area, results in greater pressure, and so the knife cuts smoothly. This is one example of a practical application of pressure. For gases, pressure is sometimes measured not as an absolute pressure, but relative to atmospheric pressure; such measurements are called gauge pressure. An example of this is the air pressure in an automobile tire, which might be said to be "220 kPa (32 psi)", but is actually 220 kPa (32 psi) above atmospheric pressure. Since atmospheric pressure at sea level is about 100 kPa (14.7 psi), the absolute pressure in the tire is therefore about 320 kPa (46 psi). In technical work, this is written "a gauge pressure of 220 kPa (32 psi)".
==== September ==== On 1 September, the National Guard attacked the Walgha, Al-Majdal and Al-Mazraa fronts with a drone, then the Internal Security Forces clashed with the National Guard, leaving 10 members of the Internal Security Forces injured, conversely, the National Guard claimed that the Internal Security Forces launched mortar rounds and fired machine guns. On 4 September, groups considered as "outlaws" forced the expulsion of Atef Hneidi, known as "al-Basha", from the Suwayda governorate, this comes after Atef Hneidi issued a statement criticizing Hikmat al-Hijri. On 6 September, clashes broke out between the National Guard and the Syrian government forces, in the villages of Rima Hazem and Al-Mansoura, involving the use of heavy machine guns. On 10 September, Syrian state television reported that "criminal groups" blocked the al-Matouna checkpoint, meanwhile, a source in Suwayda claimed that Syrian internal security forces stationed in al-Matouna blocked the passage of tourists to Damascus without any explanation. On 24 September, Syrian government forces opened fire with machine guns on the city of Suwayda, and the National Guard responded to the attacks.
Caldwell Dyson was assigned for her second space flight on November 21, 2008. Her second space mission consisted of a six-month trip to the International Space Station. Caldwell Dyson successfully lifted off on April 2, 2010, from the Baikonur spaceport on board the Soyuz TMA-18 as Flight Engineer 2 with Soyuz Commander Aleksandr Skvortsov and Flight Engineer 1 Mikhail Korniyenko. Following a two-day rendezvous and docking maneuver with the ISS, she joined Expedition 23 as a flight engineer and transferred on June 2, 2010, to Expedition 24 again as a flight engineer after the departure of the Soyuz TMA-17. During the first half of her flight, Caldwell Dyson and the Expedition 23 crew were joined by the STS-131 crew from April 7 to April 17. This period was the first and only time that four women were together on board the same spacecraft: Caldwell Dyson, NASA astronauts Stephanie Wilson and Dorothy Metcalf-Lindenburger, and JAXA astronaut Naoko Yamazaki. From May 16 to May 23, the second and last Space Shuttle visiting mission for Caldwell-Dyson's flight, STS-132, joined the Expedition 23 crew for the installation of the Russian-built module Rassvet. The second half of Caldwell Dyson's mission was marked by the failure of a coolant pump at the beginning of August. Caldwell Dyson performed her first spacewalk on August 7, 2010, with NASA astronaut Douglas Wheelock. The task for this first of three contingency EVAs was to prepare the malfunctioning coolant pump for replacement on the next spacewalks; this took place on August 11, 2010, and August 16, 2010.
== Production == In January 1995, it was reported that 20th Century Fox had secured deals with Keanu Reeves and Andrew Davis to star in and direct respectively the action thriller Dead Drop. Reeves was reportedly paid $7 million upfront against at least 5% of first-dollar gross for his role while Davis was reportedly paid $5 million. Large portions of the film were shot on location in and around Chicago, Illinois, including the University of Chicago, Argonne National Laboratory, the Museum of Science and Industry, the Field Museum of Natural History, Michigan Avenue, and the James R. Thompson Center (Atrium Mall). Additional scenes were shot at Yerkes Observatory in Williams Bay, Wisconsin, on Geneva Lake in southern Wisconsin, interiors of the U.S. Capitol were shot at the Wisconsin State Capitol, in Madison, Wisconsin, at Inland Steel Company (now known as Cleveland-Cliffs Inc.) in East Chicago, Indiana, and at a private residence in Barrington Hills, Illinois. Because of the cold Great Lakes winter and filming taking place during record-breaking winter weather, unique challenges were present for the cast and crew. Morgan Freeman noted "It was difficult for everyone, particularly for me because I'm tropical," he said. "I don't do cold weather. This is Chicago...in the winter. I was ill and in bed [for] four days at a crack. It was really rough."
Sources: en.wikipedia.org
=== 2010–2013: Films with high-profile directors === DiCaprio continued to collaborate with Scorsese in the 2010 psychological thriller film Shutter Island, based on the 2003 novel of the same name by Dennis Lehane. He played Edward "Teddy" Daniels, a U.S. Marshal investigating a psychiatric facility located on an island, who comes to question his own sanity. DiCaprio and Scorsese became interested in the project in 2007, and the former co-produced the film under Appian Way with Phoenix Pictures. Because of the film's disturbing scenes, DiCaprio had nightmares of mass murder during production and considered relaxing with his friends a form of therapy. The film was released to mixed reviews; Peter Bradshaw of The Guardian praised Scorsese's direction and the acting but criticized its twist ending. Peter Travers called it DiCaprio's "most haunting and emotionally complex performance yet", and particularly liked his cave scene with co-star Patricia Clarkson. The film was a commercial success, grossing $294 million worldwide against a budget of $80 million.
=== Neuromyotonia === Neuromyotonia refers to muscle twitching and cramping at rest that is exacerbated with exercise. It is caused by sustained or repetitive spontaneous muscle activity of peripheral nerve origin. Myokymia, or spontaneous rippling and twitching movements of muscles, is a visible component of neuromyotonia. Electromyography (EMG) discloses spontaneous, repetitive motor unit or single fiber discharges firing in irregular rhythmic bursts at high intraburst frequencies. Some of the muscles exhibiting twitching include the bilateral gastrocnemii, quadriceps femoris, biceps brachii, and right masseter. In vivo electrophysiological studies suggest at least some dysfunction of the muscle cell membrane. In the examined muscles, no abnormal insertional activity or fibrillation potentials were noted. Nerve conduction studies were normal.
For isotopes occurring at extremely low levels, accelerator mass spectrometry (AMS) can be used. For example, the decay rate of the radioisotope 14C is widely used to date organic materials, but this approach was once limited to relatively large samples no more than a few thousand years old. AMS extended the range of 14C dating to about 60,000 years BP, and is about 106 times more sensitive than conventional IRMS. AMS works by accelerating negative ions through a large (mega-volt) potential, followed by charge exchange and acceleration back to ground. During charge exchange, interfering species can be effectively removed. In addition, the high energy of the beam allows the use of energy-loss detectors, that can distinguish between species with the same mass/charge ratio. Together, these processes allow the analysis of extreme isotope ratios above 1012.
==== Dual compartment designs ==== Refrigerators with two compartments need special design to control the cooling of refrigerator or freezer compartments. Typically, the compressors and condenser coils are mounted at the top of the cabinet, with a single fan to cool them both. This arrangement has a few downsides: each compartment cannot be controlled independently and the more humid refrigerator air is mixed with the dry freezer air. Multiple manufacturers offer dual compressor models. These models have separate freezer and refrigerator compartments that operate independently of each other, sometimes mounted within a single cabinet. Each has its own separate compressor, condenser and evaporator coils, insulation, thermostat, and door. A hybrid between the two designs is using a separate fan for each compartment, the Dual Fan approach. Doing so allows for separate control and airflow on a single compressor system.
Sources: en.wikipedia.org
Cross-linking of soluble hydrophilic monomers forms a 3D insoluble netted structure which can incorporate a large amount of water. The 3D polymeric network of hydrogels is highly hydrated with 90-99% water w/w; it is capable of binding many times more water molecules when assembled than in the uncross-linked state. Hydrogel dressings can absorb up to 600 times their initial amount of water, including fluid-based wound exudates. Hydrogels are effective biomaterials for wound dressings and tissue engineering because they exchange fluid, hydrating necrotic tissues. The absorption of secretions causes the hydrogel dressing to swell, expanding the cross links in the polymer chains. The expanded 3D cross-linked network can irreversibly incorporate pathogens and detritus, thereby removing them from the wound. Some hydrogel dressings have intrinsic antimicrobial properties. Hydrogel dressings formed from antimicrobial peptides (AMPs) and chitosan have inherent antimicrobial activity. The antimicrobial properties of hydrogel dressings can be enhanced by addition of metal nanoparticles, antibiotics, or other antimicrobial agents. Silver and gold nanoparticles can also be incorporated into hydrogel dressings to enhance antimicrobial activity. Some hydrogel dressings have antibiotics such as ciprofloxacin and amoxicillin incorporated into their structure which are unloaded into the wound as fluid is exchanged. Some hydrogel dressings have incorporated stimuli-responsive nitric oxide-releasing agents and other antimicrobial agents.
Digital forensics, one application of which is to recover hidden or deleted data. Ballistics analysis which involves the evaluation of ammunition and firearms to determine which weapon might have been used in a crime. Forensic anthropology which analyzes skeletal remains to determine their cause of death or any other relevant information. Mobile forensics and social media which, since their creation, have had increased involvement in any police case, cold or not. Forensic psychology which can be used to analyze crime scenes and identify suspect profiles. Facial recognition which has been used to identify suspects based on their facial features. Artificial intelligence (AI) which is used in all of the above systems to help analyze data and information from crime scenes.
== Methods == There is a range of IQF technologies, but the main concept is to transport the product into the freezer with the help of a processing line belt or infeed shaker. Inside the freezer, the product travels through the freezing zone and exits the other side. Product transport inside the freezer uses different technologies. Some freezers use transport belts similar to a conveyor belt. Others use bed plates that hold the product, and an asymmetrical movement makes the plate advance by itself through the freezer. There are two main IQF technologies: mechanical IQF freezers and cryogenic IQF freezers. Mechanical IQF freezers work on the principle of cold air circulation, which flows from underneath the bed plate or transport belt with the help of fans. The cold airflow passes through the pieces of product in circular motions while the product is also advancing through the freezer towards the exit. The design and efficiency of this type of IQF freezers varies among manufacturers who seek to find the perfect balance of aerodynamics for an optimal freezing result. This technology has seen impressive improvements and developments during the past 20 years, being suited for an increasing range of products. Cryogenic IQF freezers immerse the product in liquid nitrogen at very low temperatures, freezing it rapidly while continuously moving the product to avoid block or lump formation. Although this method shows good freezing results, it might lead to higher processing costs per weight of product due to the cost of the liquid nitrogen required.
=== Naming === The term "type 1 diabetes" has replaced several former terms, including childhood-onset diabetes, juvenile diabetes, and insulin-dependent diabetes mellitus. Likewise, the term "type 2 diabetes" has replaced several former terms, including adult-onset diabetes, obesity-related diabetes, and noninsulin-dependent diabetes mellitus. Beyond these two types, there is no agreed-upon standard nomenclature. Diabetes mellitus is also occasionally known as "sugar diabetes" to differentiate it from diabetes insipidus. Diabetes insipidus is an unrelated disease with symptoms that can mimic diabetes mellitus.
Testosterone is the primary male sex hormone and androgen in males. In humans, testosterone drives the development of male reproductive tissues such as testicles and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. It is associated with increased aggression, sex drive, dominance, courtship display, and a wide range of behavioral characteristics. In addition, testosterone in both sexes is involved in health and well-being, where it has a significant effect on overall mood, cognition, social and sexual behavior, metabolism and energy output, the cardiovascular system, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty, accumulation of adipose fat tissue within the body, anxiety and depression, sexual performance deficits, and bone loss. Excessive levels of testosterone in men may be associated with hyperandrogenism, higher risk of heart failure, increased mortality in men with prostate cancer, and male pattern baldness. Testosterone is a steroid hormone from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites. It exerts its action through binding to and activation of the androgen receptor. In humans and most other vertebrates, testosterone is secreted primarily by the testicles of males and, to a lesser extent, the ovaries of females.
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.
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.