If you have been reading about melanotan-2 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.
Updated 2026-01-20. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
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.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
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.
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.
Though 5-HTP is found in food only in insignificant quantities, it is a chemical involved intermediately in the metabolism of tryptophan, an amino acid found in all unfractionated foods, with lower total amino acid content correlating with increased tryptophan absorption.
=== Alternative treatments === Elements bordering the metal–nonmetal dividing line are not always classified as metalloids, noting a binary classification can facilitate the establishment of rules for determining bond types between metals and nonmetals. In such cases, the authors concerned focus on one or more attributes of interest to make their classification decisions, rather than being concerned about the marginal nature of the elements in question. Their considerations may or not be made explicit and may, at times, seem arbitrary. Metalloids may be grouped with metals; or regarded as nonmetals; or treated as a sub-category of nonmetals. Other authors have suggested classifying some elements as metalloids "emphasizes that properties change gradually rather than abruptly as one moves across or down the periodic table". Some periodic tables distinguish elements that are metalloids and display no formal dividing line between metals and nonmetals. Metalloids are instead shown as occurring in a diagonal band or diffuse region. The key consideration is to explain the context for the taxonomy in use.
== Possible uses in medicine == An alternative to using GnRH analogues in IVF treatments could be short-term administration of GnSAF. During IVF, the ovaries are stimulated by raising estrogen concentrations to supraphysiological levels, which prevents the mid-cycle LH surge. Premature LH surges are unfavorable during IVF as it is associated with low oocyte viability and low success rates during IVF treatment. GnSAF could be used to influence ovarian hyperstimulation syndrome. Using GnSAF would potentially eliminate the need to use human chorionic gonadotropin. Administration of GnSAF could also be used to prevent ovulation and replace exogenously administered steroids that are often perceived as being risky, or to delay the naturally premature LH surge observed in some hyperstimulated or infertile women. GnSAF could form part of a contraceptive drug or in treatments for infertility that target LH hypersecretion or abnormal ovarian cycles.
=== Mindfulness === Langer is known for her contributions to the study of mindfulness and of mindless behaviour, which provided the basis for many studies focused on individual differences in unconscious behavior and decision-making processes in humans. Although she initially studied meditation as well, she grew to focus more on the study of mindfulness without meditation. In 1989, she published Mindfulness, arguing for the widespread influence and application of mindfulness to business, education, science, art, and interpersonal relationships, and she became known as the "mother of mindfulness". Langer defines mindfulness as "the simple act of noticing new things." The Langer Mindfulness Scale aims to proxy for measures of this form of mindfulness. Langer says that mindfulness can help teach that "uncertainty is the rule rather than the exception."
The rhodophyte, or red algae, group is a large and diverse lineage. Rhodophyte chloroplasts are also called rhodoplasts, literally "red chloroplasts". Rhodoplasts have a double membrane with an intermembrane space and phycobilin pigments organized into phycobilisomes on the thylakoid membranes, preventing their thylakoids from stacking. Some contain pyrenoids. Rhodoplasts have chlorophyll a and phycobilins for photosynthetic pigments; the phycobilin phycoerythrin is responsible for giving many red algae their distinctive red color. However, since they also contain the blue-green chlorophyll a and other pigments, many are reddish to purple from the combination. The red phycoerythrin pigment is an adaptation to help red algae catch more sunlight in deep water—as such, some red algae that live in shallow water have less phycoerythrin in their rhodoplasts, and can appear more greenish. Rhodoplasts synthesize a form of starch called floridean starch, which collects into granules outside the rhodoplast, in the cytoplasm of the red alga.
Sources: en.wikipedia.org
Tensions between Poland and its eastern neighbour, Belarus, reached a new high in June 2024 when Belarus, who had encouraged masses of illegal immigrants to cross the Polish border on foot as part of the undeclared dirty tricks campaign of its CSTO ally Russia, created the conditions in which a Polish border ground was stabbed to death by a would-be immigrant. The Polish state soon tightened controls of its frontier and on 27 July 2024 the Sejm passed a law which liberalized the use of firearms by border patrols. In June 2025 election, Karol Nawrocki, candidate of the national conservative Law and Justice (PiS), was elected Poland's new president.
Resistance has in fact appeared and may be growing. But it is remarkable that despite the sharp shifts in the distribution of power, the other great powers have not yet responded in a way anticipated by balance-of-power theory.
mRNA vaccines offer specific advantages over traditional vaccines. Because mRNA vaccines are not constructed from an active pathogen (or even an inactivated pathogen), they are non-infectious. In contrast, traditional vaccines require the production of pathogens, which, if done at high volumes, could increase the risks of localized outbreaks of the virus at the production facility. Another biological advantage of mRNA vaccines is that since the antigens are produced inside the cell, they stimulate cellular immunity, as well as humoral immunity. mRNA vaccines have the production advantage that they can be designed swiftly. Moderna designed their mRNA-1273 vaccine for COVID-19 in 2 days. They can also be manufactured faster, more cheaply, and in a more standardized fashion (with fewer error rates in production), which can improve responsiveness to serious outbreaks. The Pfizer–BioNTech vaccine originally required 110 days to mass-produce (before Pfizer began to optimize the manufacturing process to only 60 days), which was substantially faster than traditional flu and polio vaccines. Within that larger timeframe, the actual production time is only about 22 days: two weeks for molecular cloning of DNA plasmids and purification of DNA, four days for DNA-to-RNA transcription and purification of mRNA, and four days to encapsulate mRNA in lipid nanoparticles followed by fill and finish. The majority of the days needed for each production run are allocated to rigorous quality control at each stage.
== Sources == The compound arenobufagin is one of the major components of certain toad toxins. It is derived from the dried skin of giant toads, such as Bufo gargarizans and Bufo melanostictus Suhneider. Arenobufagin is specifically secreted by Rhinella arenarum, which is found in South America. The toxin of these toad species contains about 1.75% of arenobufagin. The other major part of the venom consists mostly of similar looking bufagins, which are all toxic steroids. Toads produce their toxin when they are scared, injured, or provoked, as a defense mechanism against being eaten by their predators.
Sources: en.wikipedia.org
=== Precursor to other peroxide compounds === Hydrogen peroxide is a weak acid, forming hydroperoxide or peroxide salts with many metals. It also converts metal oxides into the corresponding peroxides. For example, upon treatment with hydrogen peroxide, chromic acid (CrO3 and H2SO4) forms a blue peroxide CrO(O2)2.
== Uses == The stilbenoid oxyresveratrol can be isolated from the heartwood of Artocarpus lacucha as well as in Puag Haad, the light brown powder obtained from the aqueous extract of the wood chips of A. lakoocha by boiling, then slow evaporation, followed by cooling. This traditional drug is effective against the intestinal fluke Haplorchis taichui or against taeniasis. Experiments have shown that the heme-peroxidase enzyme from Artocarpus lacucha has the ability to protect against oxidative damage in vitro and possesses wound healing properties. This stable enzyme also has anti-inflammatory properties, making it a potential candidate for use in biotechnological and industrial applications.
The public inquiry into the 2017 Manchester Arena bombing finds that MI5 missed a significant chance to take action that might have stopped the attack when they failed to obtain intelligence that would have led them to follow Salman Abedi to the car where he was storing explosives. Ken McCallum, the director-general of MI5, says he regrets that the intelligence was missed. 3 March COVID-19 in the UK: Lockdown Files: The latest leaked WhatsApp messages published by the Daily Telegraph are reported as appearing to show former Health Secretary Matt Hancock and Cabinet Secretary Simon Case joking about locking people in quarantine hotels. Office for National Statistics data for the week up to 21 February indicates that COVID-19 infections were increasing in England and Wales, but decreasing in Northern Ireland, while the situation in Scotland was uncertain. In England, the number of people testing positive for COVID-19 was estimated to be 1,298,600 (roughly 2.31% of the population around 1 in 45). The Commons Select Committee of Privileges finds that former prime minister Boris Johnson may have misled Parliament over the Partygate scandal after evidence suggested breaches of COVID-19 rules would have been "obvious" to him. In response Johnson says that none of the evidence shows he "knowingly" misled parliament, and that "it is clear from this report that I have not committed any contempt of parliament". Buckingham Palace announces the first state visit to be made by Charles III and Camilla as King and Queen Consort; they will travel to France and Germany from 26 to 31 March.
=== Novel applications === Due to the versatility of SPR instrumentation, this technique pairs well with other approaches, leading to novel applications in various fields, such as biomedical and environmental studies. When coupled with nanotechnology, SPR biosensors can use nanoparticles as carriers for therapeutic implants. For instance, in the treatment of Alzheimer's disease, nanoparticles can be used to deliver therapeutic molecules in targeted ways. In general, SPR biosensing is demonstrating advantages over other approaches in the biomedical field due to this technique being label-free, lower in costs, applicable in point-of-care settings, and capable of producing faster results for smaller research cohorts. In the study of environmental pollutants, SPR instrumentation can be used as a replacement for former chromatography-based techniques. Current pollution research relies on chromatography to monitor increases in pollution in an ecosystem over time. When SPR instrumentation with a Kretschmann prism configuration was used in the detection of chlorophene, an emerging pollutant, it was demonstrated that SPR has similar precision and accuracy levels as chromatography techniques. Furthermore, SPR sensing surpasses chromatography techniques through its high-speed, straightforward analysis.
26 July – Three men are killed in a car crash on a road near Dunmore; a woman also involved in the incident is being treated in hospital. The Flow Country of Caithness and Sutherland is named as a World Heritage Site. 30 July – Unison confirms that refuse workers in 14 Scottish council areas will strike from 14 to 22 August. 31 July – The Unite and GMB unions announce eight days of strike action for refuse workers beginning on 14 August, which will include those working for Edinburgh City Council and occur during the Edinburgh Festival.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
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.