Everything below concerns Melanotan II. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
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.
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.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
In late October, Gaza's premature babies faced a critical situation as Medical Aid for Palestinians and UNICEF warned that 130 infants were at risk of death due to a hospital fuel shortage caused by Israel's siege. The lack of fuel led to power outages, endangering premature babies in neonatal intensive care units (NICUs). Despite assurances from the IDF to assist in evacuations, the Gaza Health Ministry reported a lack of evacuation mechanisms, resulting in the deaths of several infants. The situation escalated in mid-November when Israel launched a raid on al-Shifa Hospital. Evacuations eventually occurred, facilitated by the Palestinian Red Crescent, World Health Organization, and UNOCHA, with 31 premature babies moved to southern Gaza, with most then to Egypt. Not all infants were accompanied by their parents, and two died at al-Shifa before the evacuation. The distress extended to Al-Nasr Children's Hospital, bombed by the IDF in early November, where medical workers had to leave babies in incubators during evacuation. Video footage later revealed the aftermath, with five premature babies found dead in their incubators. The IDF initially denied responsibility, though an Israel official was heard providing assurances to evacuate the hospital in a released audio. In mid-December, a military siege on Kamal Adwan Hospital worsened the situation, as IDF soldiers reportedly prevented staff from supporting 12 babies in intensive care.
==== Juvenile breast hypertrophy ==== In 1993, the Japanese journal Surgery Today reported on the case of a 12-year-old girl. Only 152 centimetres (60 in) tall and weighing 43 kilograms (95 lb), her breasts began to develop at age 11 before the onset of menstruation. Over the next eight months, both breasts grew abnormally large, and physicians treating her found that her physiological development was normal except for her breasts. The weight produced by their symmetrical and massive enlargement resulted in marked curvature of the spine. Lab tests of her blood for hormones and biochemical substances showed normal values, though tests revealed that it might have been caused by hypersensitivity to estrogen. She underwent a bilateral reduction mammoplasty. Surgeons removed 2 kilograms (4.4 lb) of tissue from her right breast and 1.9 kilograms (4.2 lb) from her left breast. She was administered tamoxifen afterward to suppress breast regrowth. A more severe case of juvenile breast hypertrophy of an 11-year-old girl was reported in 2008. The breasts had begun to grow rapidly at puberty and had reached the point of causing physical and psychological impairment and possible respiratory compromise after ten months. The skin was intact without any ulcerations. Blood chemistry and endocrine investigation was normal. A bilateral reduction mammaplasty with free nipple grafts was performed. 6 kg (13 lb) of the right breast and 6.5 kg (14 lb) of the left breast were removed, resulting in a removal of 12.5 kg (28 lb) of tissue in all (24% of the total body weight).
There are varied reasons for e-cigarette use. Most users are trying to quit smoking, but some use is recreational or as an attempt to get around smoke-free laws. Many people vape to relax, and some because vaping is safer than smoking. The wide choice of flavors and lower price compared to cigarettes are also important factors. Other motivations include reduced odor and fewer stains. E-cigarettes also appeal to technophiles who enjoy customizing their devices.
Sources: en.wikipedia.org
The Ottomans, through the Ma'n dynasty, a great Druze feudal family, and the Shihabs, a mixed Sunni Muslim-Druze family that had converted to Christianity. Ma'n dynasty were a family of Druze chiefs of Arab stock based in the rugged Chouf area of southern Mount Lebanon who were politically prominent in the 15th–17th centuries. Deir al-Qamar was the capital and the residence of the Emirate of Mount Lebanon. The Church of Saidet et Tallé is a Maronite church in Deir el Qamar in Lebanon, it is one of the most important historical and religious sites in Deir el Qamar and dates to the 16th century. The second church was destroyed by the Saracens and rebuilt during Fakhreddine 1st Maan's (1518–1544) reign. In 1673, Sheikh Abu Fares Karam of Ehden (Emir Ahmad Ma'n's secretary) and his brother Sheikh Abu Nader enlarged the church and added a vault. During the reign of Bechir II Chehab (1789–1840) it was again enlarged and renovated. Fakhr-al-Din II (1572–1635) was a Druze prince and a leader of the Mount Lebanon Emirate. For uniting modern Lebanon's constituent parts and communities, especially the Druze and the Maronites, under a single authority for the first time in history, he is generally regarded as the country's founder. Christians prospered and played key roles under his rule, with his main enduring legacy being the symbiotic relationship he set in motion between Maronites and Druze, which proved foundational for the creation of a Lebanese entity. Maronite Abū Nādir al-Khāzin was one of his foremost supporters and served as Fakhr-al-Din's adjutant.
Cosmetics are regulated by the Center for Food Safety and Applied Nutrition, the same branch of the FDA that regulates food. Cosmetic products are not, in general, subject to premarket approval by the FDA unless they make "structure or function claims" that make them into drugs (see Cosmeceutical). However, all color additives must be specifically FDA approved before manufacturers can include them in cosmetic products sold in the U.S. The FDA regulates cosmetics labeling, and cosmetics that have not been safety tested must bear a warning to that effect. According to the industry advocacy group, the American Council on Science and Health, though the cosmetic industry is primarily responsible for its own product safety, the FDA can intervene when necessary to protect the public. In general, though, cosmetics do not require pre-market approval or testing. The ACSH says that companies must place a warning note on their products if they have not been tested, and that experts in cosmetic ingredient review also play a role in monitoring safety through influence on ingredients, but they lack legal authority. According to the ACSH, it has reviewed about 1,200 ingredients and has suggested that several hundred be restricted—but there is no standard or systemic method for reviewing chemicals for safety, or a clear definition of what 'safety' even means so that all chemicals get tested on the same basis.
== External links == Quantities, Units and Symbols in Physical Chemistry (IUPAC green book) An introductory video on Mass Spectrometry The Royal Society of Chemistry NIST Standard Reference Database 1A v17
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
Purity is normally stated as an area percentage from high-performance liquid chromatography, for example ninety-five or ninety-eight percent. That figure describes the proportion of ultraviolet-absorbing material eluting as the main peak. It says nothing about water content, counterions, residual solvents or mass fraction of the peptide itself.