The short version of melanotan-2 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-19. Anything still debated is marked as such rather than presented as settled.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
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.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
== Treatment == Treatment of GAMT deficiency focuses on restoration of depleted brain creatine with oral creatine supplementation in pharmacologic doses, and removal of toxic intermediate GAA via ornithine supplementation and arginine- or protein-restricted diet. Sodium benzoate supplementation is also sometimes used to decrease GAA levels. All patients are reported to benefit from creatine supplementation, with possible improvements or stabilization in symptoms. Seizures appear to reduce more with dietary arginine restriction and ornithine supplementation. Despite treatment, none of the patients have been reported to return to completely normal developmental level, if significant damage had taken place before treatment. Prior to the addition of GAMT deficiency to newborn screening panels, younger siblings of affected individuals may have been tested at birth and treated early. This early treatment can result in outcomes that are very close to normal.
In the United States the press began using the terms "Jewish National Home", "Jewish State", "Jewish republic" and "Jewish Commonwealth" interchangeably. Treaty expert David Hunter Miller, who was at the conference and subsequently compiled a 22 volume compendium of documents, provides a report of the Intelligence Section of the American Delegation to the Paris Peace Conference of 1919 which recommended that "there be established a separate state in Palestine," and that "it will be the policy of the League of Nations to recognize Palestine as a Jewish state, as soon as it is a Jewish state in fact." The report further advised that an independent Palestinian state under a British League of Nations mandate be created. Jewish settlement would be allowed and encouraged in this state and this state's holy sites would be under the control of the League of Nations. Indeed, the Inquiry spoke positively about the possibility of a Jewish state eventually being created in Palestine if the necessary demographics for this were to exist. Historian Matthew Jacobs later wrote that the US approach was hampered by the "general absence of specialist knowledge about the region" and that "like much of the Inquiry's work on the Middle East, the reports on Palestine were deeply flawed" and "presupposed a particular outcome of the conflict". He quotes Miller, writing about one report on the history and impact of Zionism, "absolutely inadequate from any standpoint and must be regarded as nothing more than material for a future report".
Amino acids (two proteinogenic: cysteine and methionine, and many other non-coded: cystine, taurine, etc.) and two vitamins (biotin and thiamine) are organosulfur compounds crucial for life. Many cofactors also contain sulfur, including glutathione, and iron–sulfur proteins. Disulfides, S–S bonds, confer mechanical strength and insolubility of the (among others) protein keratin, found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for biochemical functioning and is an elemental macronutrient for all living organisms.
In April 2002, Yosri Fouda of Al Jazeera met al-Qaeda member Khalid Sheikh Mohammed and bin al-Shibh, who were in hiding, and they admitted to him their involvement in the attacks. Mohammed had been an organizer and financier of al-Qaeda's 1993 bombing of the World Trade Center, and he was the uncle of Ramzi Yousef, the lead bomber in that attack. Mohammed and Yousef planned another terrorist attack, the Bojinka plot, for January 1995. Despite its failure, and Yousef's imprisonment by the U.S. afterwards, the plot would influence the later September 11 attacks. The 2004 9/11 Commission Report determined that the animosity that Mohammed, the principal architect of 9/11, felt towards the U.S. had stemmed from his "violent disagreement with U.S. foreign policy favoring Israel."
Sources: en.wikipedia.org
=== Brand names === Ethylestrenol is or has been marketed under a variety of brand names including Durabolin O, Duraboral, Fertabolin, Maxibolin, Maxibolin Elixir, Orabolin, Orgabolin, Orgaboral, and Virastine. The brand name Durabolin O is a contraction of "Durabolin Oral", Durabolin being a brand name of the nandrolone ester nandrolone phenylpropionate. Ethylestrenol is or has also been marketed for veterinary use under the brand names Nandoral, Nitrotain, and Oestrotain.
Honey use and production has a long and varied history, with its beginnings in prehistoric times. Several cave paintings in Cuevas de la Araña in Spain depict humans foraging for honey at least 8,000 years ago. While Apis mellifera is an Old World insect, large-scale meliponiculture of New World stingless bees has been practiced by Mayans since pre-Columbian times.
Europe has a basic choice: either it lapses back into the old power politics and balance of power diplomacy of past centuries or it moves ahead along the road leading to a new order of peace and freedom, whether this be based on multinational or supranational cooperation. Our choice is clear: we are going forward.According to historian Sverre Bagge, a balance of power logic may have prevented unification of the three Scandinavian kingdoms (Norway, Sweden and Denmark), as balancing coalitions formed to prevent one kingdom from conquering the other kingdoms.
The Australian National University Act received royal assent on 1 August 1946. The act created the Australian National University (ANU), and gave the medical research institute the name "John Curtin School of Medical Research". H. C. "Nugget" Coombs, an economist and head of the Department of Post-War Reconstruction, accompanied the Prime Minister, Ben Chifley, on an official visit to the UK as his principal advisor. Coombs met with Florey in Oxford in May 1946. They agreed that the success of the new university would depend on the quality of faculty they could attract, and he wanted four eminent scholars to lead the four research schools: Florey for medicine, Mark Oliphant for physics, Keith Hancock for history, and Raymond William Firth for Pacific studies. Each received an official invitation in April 1947, and they were invited to come to Canberra for consultation in December 1947 and January 1948. They would constitute an academic advisory committee, for which they would be paid £250 (equivalent to A$20,242 in 2022) plus £200 (equivalent to A$16,193 in 2022) expenses per annum. Since they were all located in the UK, a London office of the university was opened to provide liaison. Florey never moved to Canberra, but he did accept the position of acting director of the John Curtin School of Medical Research for a five-year term commencing in May 1948 in order to establish it. Brian Lewis had been appointed university architect, but Florey hired Stephen Welsh, the professor of architecture at Sheffield University.
Reactions of acids are often generalized in the form HA ⇌ H+ + A−, where HA represents the acid and A− is the conjugate base. This reaction is referred to as protolysis. The protonated form (HA) of an acid is also sometimes referred to as the free acid. Acid–base conjugate pairs differ by one proton, and can be interconverted by the addition or removal of a proton (protonation and deprotonation, respectively). The acid can be the charged species and the conjugate base can be neutral in which case the generalized reaction scheme could be written as HA+ ⇌ H+ + A. In solution there exists an equilibrium between the acid and its conjugate base. The equilibrium constant K is an expression of the equilibrium concentrations of the molecules or the ions in solution. Brackets indicate concentration, such that [H2O] means the concentration of H2O. The acid dissociation constant Ka is generally used in the context of acid–base reactions. The numerical value of Ka is equal to the product (multiplication) of the concentrations of the products divided by the concentration of the reactants, where the reactant is the acid (HA) and the products are the conjugate base and H+.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
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.