This is a working overview of Melanotan II, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-10. Anything still debated is marked as such rather than presented as settled.
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.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
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.
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.
In 1990, a team of speleologists uncovered eight mummies, dating back to around 1283 AD, during a rescue excavation in the e 'Asi al-Hadath cave in the Qadisha Valley of Lebanon. The well-preserved spontaneous mummies, including an infant named dubbed Yasmine, offer insights into Maronite villagers' lives during the Mamluk era. The grotto's high altitude and dry conditions naturally mummified the bodies. The discovery provides historical context, aligning with documented Mamluk raids in the region. Artifacts, including pottery with inscriptions, manuscripts, and clothing, suggest a Maronite community, and the mummies' burial practices parallel present-day Lebanese customs. The remains were called "Maronite mummies" because the individuals found in the 'Asi-al Hadath cave were believed to be Maronites, an indigenous Christian community in the region. Some of the mummies have been transferred to the National Museum of Beirut.
== Synthesis and Post-translational Modification == Proinsulin is synthesized on membrane associated ribosomes found on the rough endoplasmic reticulum, where it is folded and its disulfide bonds are oxidized. It is then transported to the Golgi apparatus where it is packaged into secretory vesicles, and where it is processed by a series of proteases to form mature insulin. Mature insulin has 35 fewer amino acids; 4 are removed altogether, and the remaining 31 form the C-peptide. The C-peptide is abstracted from the center of the proinsulin sequence; the two other ends (the B chain and A chain) remain connected by disulfide bonds. The post translational modification of proinsulin to mature insulin only occurs in the beta cells of the pancreatic islets. When proinsulin is transported through the Golgi apparatus the C-peptide is cleaved. This cleavage occurs with the aid of two endoproteases. Type I endoproteases, PC1 and PC3, disrupt the C peptide-B chain connection. PC2, a type II endoprotease, cleaves the C peptide-A chain bond. The resulting molecule, now mature insulin, is stored as a hexamer in secretory vesicles and is stabilized with
== Nobel Prize == After the news about the curative properties of penicillin broke in an editorial in The Times on 27 August 1942, Fleming enjoyed the publicity, but Howard Florey did not: he feared that this would create a demand for penicillin that he did not yet have to give. When the press arrived at the Sir William Dunn School, he told his secretary to "send them packing". He also prohibited his team from speaking to the press. Confusion resulted from the fact that the mould juice and the drug produced from it were both called penicillin. Distorted and inaccurate accounts were published and broadcast giving Fleming credit for the development of penicillin, accounts that Fleming and St. Mary's Hospital made little or no effort to correct. The story the media wished to tell was the familiar one of the lone scientist and the serendipitous discovery. The British medical historian Bill Bynum later wrote:The discovery and development of penicillin is an object lesson of modernity: the contrast between an alert individual (Fleming) making an isolated observation and the exploitation of the observation through teamwork and the scientific division of labour (Florey and his group). The discovery was old science, but the drug itself required new ways of doing science.
In early September 2024, Little Caesars announced that it would be exiting Singapore, with the last day of operations for the chain being September 30. The last store was in Funan, after the gradual closure of the chain's six other branches throughout the island. In 2022, Little Caesars had plans to expand into France, Germany, and Portugal. In July 2025, Little Caesars expanded to the United Arab Emirates, opening its first branch in Al Barsha, Dubai In May 2026, Little Caesars expanded to Malaysia, opening its first branch in Damansara Utama.
Australian labour law sets the rights of working people, the role of trade unions, and democracy at work, and the duties of employers, across the Commonwealth and in states. Under the Fair Work Act 2009, the Fair Work Commission creates a national minimum wage and oversees National Employment Standards for fair hours, holidays, parental leave and job security. The FWC also creates modern awards that apply to most sectors of work, numbering 150 in 2024, with minimum pay scales, and better rights for overtime, holidays, paid leave, and superannuation for a pension in retirement. Beyond this floor of rights, trade unions and employers often create enterprise bargaining agreements for better wages and conditions in their workplaces. In 2024, collective agreements covered 15% of employees, while 22% of employees were classified as "casual", meaning that they lose many protections other workers have. Australia's laws on the right to take collective action are among the most restrictive in the developed world, and Australia does not have a general law protecting workers' rights to vote and elect worker directors on corporation boards as do most other wealthy OECD countries. Equal treatment at work is underpinned by a patchwork of legislation from the Fair Work Act 2009, Racial Discrimination Act 1975, Sex Discrimination Act 1984, Disability Discrimination Act 1992, Age Discrimination Act 2004 and a host of state laws, with complaints possible to the Fair Work Commission, the Australian Human Rights Commission, and state-based regulators.
Sources: en.wikipedia.org
Denys performed another transfusion into a labourer, who also survived. Both instances were likely due to the small amount of blood that was actually transfused into these people. This allowed them to withstand the allergic reaction. Denys's third patient to undergo a blood transfusion was Swedish Baron Gustaf Bonde. He received two transfusions. After the second transfusion Bonde died. In the winter of 1667, Denys performed several transfusions on Antoine Mauroy with calf's blood. On the third account Mauroy died. Six months later in London, Lower performed the first human transfusion of animal blood in Britain, where he "superintended the introduction in [a patient's] arm at various times of some ounces of sheep's blood at a meeting of the Royal Society, and without any inconvenience to him." The recipient was Arthur Coga, "the subject of a harmless form of insanity." Sheep's blood was used because of speculation about the value of blood exchange between species; it had been suggested that blood from a gentle lamb might quiet the tempestuous spirit of an agitated person and that the shy might be made outgoing by blood from more sociable creatures. Coga received 20 shillings (equivalent to £206 in 2025) to participate in the experiment. Lower went on to pioneer new devices for the precise control of blood flow and the transfusion of blood; his designs were substantially the same as modern syringes and catheters. Shortly after, Lower moved to London, where his growing practice soon led him to abandon research.
=== Weight-bearing activity === The results produced by aerobic activity were repeated in 1999 where for 12 weeks, weight-bearing exercise was added for patients not exhibiting marked physical incapacity as measured by the Functional Index in Myositis (see Functional Assessment section). Confirmed by MRI and muscle biopsy, both the 1998 and 1999 studies showed that there were no significant changes in levels of creatine kinase and aldolase, and no increase in muscle inflammation. In 2001, 22 patients were placed on a three-week physical therapy and exercise program, and found that creatine kinase levels actually dropped in 20 of the patients. The longest study to date was a six-month exercise program demonstrating a significant improvement in exercise capacity, VO2, isokinetic strength, and the ability to perform daily tasks compared to controls.
The Treaty on the Functioning of the European Union articles 28 to 37 establish the principle of free movement of goods in the EU, while articles 45 to 66 require free movement of persons, services and capital. These "four freedoms" were thought to be inhibited by physical barriers (e.g. customs), technical barriers (e.g. differing laws on safety, consumer or environmental standards) and fiscal barriers (e.g. different Value Added Tax rates). Free movement and trade is not meant to be a licence for unrestricted commercial profit. Increasingly, the Treaties and the Court of Justice aim to ensure free trade serves higher values such as public health, consumer protection, labour rights, fair competition, and environmental improvement.
== Diagnosis == While heterotopic bone growth can begin spontaneously in FOP patients, Eastlack, like most patients, first experienced a triggered proliferation due to an illness or injury. When he was three or four years old, in 1937, while playing with his sister Helene, on a local street, a car hit him and injured his leg. He was taken to the hospital where his leg was put in a cast before returning home. The fracture never set properly, and when the cast was removed months later, his leg was painfully swollen with a high amount of inflammation. No further action was taken and shortly after, Eastlack began to experience his first set of abnormal bone growths. His hips and knees had become difficult to move. When he was taken to the hospital with this concern, the doctor took X-rays in which the bony deposits on his thigh muscles were revealed. The doctors were not able to diagnose his condition having seen this, and it continued to progress in the anatomically characteristic manner that FOP does. Eastlack soon suffered flare-ups along his back, neck, and chest. In attempts to diagnose and treat Eastlack's condition, the doctors ordered biopsies and performed a total of 11 surgical procedures to remove excess and heterotopic ossification, such as that on his thigh muscles. However, Eastlack's condition was aggravated by such procedures and the bone plates returned thicker and more predominant. It was 1938, the year after the incident, when he was finally diagnosed with myositis ossificans progressiva, which is now known as fibrodysplasia ossificans progressiva (FOP).
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
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.