alpha-MSH analog comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-06-30. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
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.
=== Synthetic organic chemistry === BCATs have been used in the synthesis of some pharmaceutical drugs as an alternative to heavy metal catalysts, which can be expensive/environmentally unfriendly. Aminotransferases (transaminases) in general have been used to create unnatural amino acids, important building blocks for peptidomimetic drugs and agricultural products. BCAT from E. coli is typically engineered to be overexpressed and extracted from whole cells to be used for chemical synthesis. Aminotransferases are used because they can accomplish a typically multi-step reaction in one step, can perform reactions on a wide range of substrates, and have high regioselectivity and enantioselectivity. In synthetic organic chemistry, BCATs are typically used for the conversion of L-Leucine to 2-ketoglutarate.
== Phylogeny == The five currently known genera of FAP organisms are Chloroflexus, Choronema, Oscillochloris, Roseiflexus, and Heliothrix. Of these five, only two do not contain chlorosomes: Roseiflexus and Heliothrix. Roseiflexus and Heliothrix are both red due to only having Bchl a as a photosynthetic pigment. In most other aspects, both phenotypically and genetically, the genera Roseiflexus and Heliothrix are different from each other. Little is known about the taxonomy of the Roseiflexus genus due to it only containing one known species: Roseiflexus casternholzii.
=== U.S. relations with Marshall Islands === Section 177 of the 1983 Compact of Free Association between the governments of the United States and the Marshall Islands establishes a process for Marshallese to make a claim against the United States government as a result of damage and injury caused by nuclear testing. That same year, an agreement was signed to implement Section 177, which established a US$150 million trust fund. The fund was intended to generate US$18 million a year, which would be payable to claimants on an agreed-upon schedule. If the US$18 million a year generated by the fund was not enough to cover claims, the principal of the fund could be used. A Marshall Islands Nuclear Claims Tribunal was established to adjudicate claims. In 2000, the tribunal made a compensation award to the people of Enewetak consisting of US$107.8 million for environmental restoration; US$244 million in damages to cover economic losses caused by loss of access and use of the atoll; and US$34 million for hardship and suffering. In addition, as of the end of 2008, another US$96.658 million in individual damage awards were made. Only US$73.526 million of the individual claims award has been paid, however, and no new awards were made between the end of 2008 and May 2010. Due to stock market losses, payments rates that have outstripped fund income, and other issues, the fund was nearly exhausted, as of May 2010, and unable to make any additional awards or payments.
Sources: en.wikipedia.org
Hitchens supported Ralph Nader in the 2000 US presidential election. He elaborated on his support for Nader in a discussion with Eric Alterman on Bloggingheads.tv, indicating that he was disenchanted with the candidacy of both George W. Bush and Al Gore. Prior to the September 11 attacks in 2001, and the invasion of Iraq and Afghanistan, Hitchens was critical of President George W. Bush's "non-interventionist" foreign policy. He also criticised Bush's support for intelligent design and capital punishment. Hitchens defended Bush's post-11 September foreign policy, but he also criticised the actions of US troops in Abu Ghraib and Haditha, and the US government's use of waterboarding, which, after voluntarily undergoing it, he argued was definitely torture. After Dick Cheney chief of staff Scooter Libby was found guilty of obstruction of justice and perjury, Hitchens defended Libby and called on Bush to pardon him. Hitchens supported George W. Bush in the 2004 US presidential election. He made a brief return to The Nation just before the election and wrote that he was "slightly" for Bush; shortly afterwards, Slate polled its staff on their positions on the candidates and mistakenly printed Hitchens' vote as pro-John Kerry. Hitchens shifted his opinion to "neutral", saying: "It's absurd for liberals to talk as if Kristallnacht is impending with Bush, and it's unwise and indecent for Republicans to equate Kerry with capitulation. There's no one to whom he can surrender, is there? I think that the nature of the jihadist enemy will decide things in the end".
Dermal macrophages are primarily populated in the dermis of the skin as they are specialised in skin homeostasis and repair. There are three inter-linked stages in skin wound healing: inflammation, tissue formation, and maturation. Dermal macrophages serve the function of bridging the three stages of wound healing. The first stage occurs from day 0 to 5 post-injury. This stage is an inflammatory response induced by dermal macrophages to initiate the tissue repairing process. Similar to their functions in innate immunity, dermal macrophages stimulate an inflammatory response during the first stage of wound repair by releasing pro-inflammatory factors. This allows infiltration of immune cells and factors facilitating tissue regeneration. Dermal macrophages are associated with the production of proliferation factors such as TGFβ1 and VEGF-A. The factors are produced to initiate the second stage, tissue formation. Tissue formation occurs from day 5 to 10 post-injury. In this stage, dermal macrophages' primary role is to generate a primary structure for wound repairing via granulation and collagen deposition. They also mediate re-epithelialisation and neo-angiogenesis by producing TGFβ1 and VEGF-A, as in the inflammation stage. Dermal macrophages are essential in the transition between the second and third stages. Deficiency in dermal macrophages might induce unfavourable morphological changes in the wound because of compromised removal of tissue debris via phagocytosis. Dermal macrophages mediate the final stage of tissue maturation and wound remodelling.
patent 2,666,298 was issued on January 19, 1954 – Methods and means of defrosting a cold diffuser. U.S. patent 2,696,086 was issued on December 7, 1954 – Method and means for air conditioning. U.S. patent 2,780,923 was issued on February 12, 1957 – Method and means for preserving perishable foodstuffs in transit. U.S. patent 2,850,001 was issued on September 2, 1958 – Control device for internal combustion engine. U.S. patent 2,926,005 was issued on February 23, 1960 – Thermostat and temperature control system.
Sources: en.wikipedia.org
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
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.