If you have been reading about alpha-MSH analog 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 2026-06-27. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 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.
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.
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.
| 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 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.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
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.
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.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
== Awards == 2015 Sundance Film Festival Winner, Special Jury Award for Dramatic Feature: Advantageous Nominee, Grand Jury Prize for Dramatic Feature: Advantageous LA Asian Pacific Film Fest Winner, Editing, score, and directing awards for Advantageous (feature) - 2015 Winner, Golden Reel Award for Excellence in Short Film: Advantageous - 2013 2012 Rhode Island Horror Film Festival Winner, Best Science Fiction Film: Advantageous (Short) Asian American International Film Festival Winner, Best Narrative: Half Life - 2008 Winner, Emerging Director Award for Best Feature: Half Life - 2008 Nominee, Excellence in Short Filmmaking Award: Futurestate - 2013 Austin Fantastic Fest Nominee, Short Film Award: Advantageous (short) - 2012 Cleveland International Film Festival Nominee, Best Women's Short Film: Advantageous (short) - 2013 Nominee, Best Live Action Short Film: Advantageous (short) - 2013 Film Independent Spirit Awards Nominee, John Cassavetes Award: (2016) Shared with Jacqueline Kim, Robert M.
Eurogamer echoed criticism on the game's length; reviewer Tom Bramwell commented that "although I'm hard pressed to criticize what you get, the complete absence of everything we've learnt from the likes of Counter-Strike and everything since is frankly bizarre". Bramwell did, however, criticize the game's artificial intelligence and the occasional bug that caused a player to get stuck on a wall. PC Zone's Mark Hill was more lenient, praising the game's artificial intelligence as "intelligent as you could hope an AI enemy to be". In addition, Hill praised the game for showing more activity in the base, noting that "a whole world goes on around you, with people eating at a cantina and scientists doing their laundry. The complex is more alive than ever before". Hill also praised the focus "on a greater interaction with scientists as proper people rather than the two or three models that were cloned throughout the facility who kept repeating the same phrases", describing this as Blue Shift's "greatest achievement". PC Zone's review closed by commenting that "as a Dreamcast extra it works perfectly, but as a standalone PC title there's not nearly enough to it." In his negative review of the game, Jim Preston of NextGen recommended that players play the Half-Life mods They Hunger or Day of Defeat instead. The game sold around 800,000 units at retail, excluding digital sales on Steam.
The isotopic compositions of ice cores from continental ice sheets and alpine glaciers have been developed as temperature proxies since the 1950s. Samuel Epstein was one of the first to show the applicability of this proxy by measuring oxygen isotopes in Antarctic snow, and also pointed out complications in the stable isotope-temperature correlation caused by the history of the air masses from which the snow formed. Ice cores in Greenland and Antarctica can be thousands of meters thick and record snow isotopic composition of the past few glacial-interglacial cycles. Ice cores can be dated by layer counting on the top and ice flow modeling at depth, with additional age constraints from volcanic ash. Cores from Greenland and Antarctica can be aligned in age at high-resolution by comparing globally well-mixed trace gas (e.g. CH4) concentrations in the air bubbles trapped in the cores. Some of the first ice core records from Greenland and Antarctica with age estimates go back to the last 105 years, and showed a depletion in δD and δ18O in the last ice age. The ice core record has since been extended to the last 800,000 years in Antarctica, and at least 250,000 years in Greenland. One of the best δD-based ice core temperature records is from the Vostok ice core in Antarctica, which goes back to 420,000 years. The δD-temperature (of the inversion layer where snow forms) conversion in east Antarctica based on modern spatial gradient of δD (9‰/°C) is ΔTI=(ΔδDice-8Δδ18Osw)/9, which takes into account variations in seawater isotopic composition caused by global ice volume changes.
Sources: en.wikipedia.org
== Limitations == Despite its aforementioned advantages as a specialized tool, the B1H system does have some drawbacks. First, the B1H selection system is limited in its capacity to determine the binding specificities of transcription factors with lengthy binding sites. This arises from the fact that the number of randomized “prey” clones required to represent all possible target sequences increases exponentially with the number of nucleotides in that target sequence. Second, some eukaryotic factors may not express or fold efficiently in the bacterial system, attributed to differing regulatory networks and transcriptional machinery. Hence when working with DNA-binding proteins of eukaryotic origin, a yeast-based hybrid system may be beneficial. Third, the B1H system may not be ideally suited for transcription factors that recognize binding sites with low affinity. The logic here is that competition created by binding sites elsewhere in the bacterial genome may limit the signal that can be realized from a single binding site that is present upstream of the reporter.
=== Criminal justice === Kennedy opposed the First Step Act, a bipartisan criminal justice reform bill. The bill passed 87–12 on December 18, 2018. Kennedy said the bill did not do enough to protect victims of crime, saying, "This is not a criminal justice bill. It is a prisoner release bill. We should be protecting victims of crimes and not the offenders who committed the crimes." In 2023, he introduced a bill that would lower the amount of fentanyl a dealer must possess to face the mandatory minimum prison sentence. Kennedy has criticized prosecutors for declining to prosecute some offenders. In 2023, he introduced the Prosecutors Need to Prosecute Act, which requires prosecutors to disclose when they decline to prosecute cases. It would also remove funding for prosecutors who fail to report such cases.
== Taxonomy == This species was originally noted and named in 1753 by Carl Linnaeus as Agaricus campestris. It was placed in the genus Psalliota by Lucien Quelet in 1872. Some variants have been isolated over the years, a few of which now have species status, for example, Agaricus bernardii Quel. (1878), Agaricus bisporus (J.E. Lange) Imbach (1946), Agaricus bitorquis (Quel.) Sacc. (1887), Agaricus cappellianus Hlavacek (1987), and Agaricus silvicola (Vittad.) Peck (1872). Some were so similar they did not warrant even varietal status, while others have retained it. Agaricus campestris var. equestris (F.H.Moller) Pilat (1951) is still valid. A. campestris var. isabellinus (F.H.Moller) Pilat (1951), and A. campestris var. radicatus, are possibly still valid too. The Latin specific epithet campestris means "of the fields". Common names given to the fungus include "meadow mushroom", "pink bottom", and "field mushroom". An analysis of ribosomal DNA of a limited number of members of the genus showed A. campestris to be an early offshoot in the genus and sister taxon to A. cupreobrunneus.
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.
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.