Everything below concerns MC1R. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-08-13. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms add to total mass |
| Molecular mass | About 1024 daltons | Calculated for the free base |
| Structural class | Cyclic heptapeptide | Contains D-phenylalanine and norleucine |
| Parent hormone | Alpha-melanocyte-stimulating hormone | Endogenous tridecapeptide of 13 residues |
| Receptor profile | Non-selective melanocortin agonist | Interacts with MC1R, MC3R, MC4R and MC5R |
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.
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.
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.
== Mechanism of action == Antipsychotic drugs such as haloperidol and chlorpromazine tend to block dopamine D2 receptors in the dopaminergic pathways of the brain. This means that dopamine released in these pathways has less effect. Excess release of dopamine in the mesolimbic pathway has been linked to psychotic experiences. Decreased dopamine release in the prefrontal cortex, and excess dopamine release in other pathways, are associated with psychotic episodes in schizophrenia and bipolar disorder. In addition to the antagonistic effects of dopamine, antipsychotics (in particular atypical antipsychotics) also antagonize 5-HT2A receptors. Different alleles of the 5-HT2A receptor have been associated with schizophrenia and other psychoses, including depression. Higher concentrations of 5-HT2A receptors in cortical and subcortical areas, in particular in the right caudate nucleus have been historically recorded. Typical antipsychotics are not particularly selective and also block dopamine receptors in the mesocortical pathway, tuberoinfundibular pathway, and the nigrostriatal pathway. Blocking D2 receptors in these other pathways is thought to produce some unwanted side effects that the typical antipsychotics can produce (see above). Antipsychotics were commonly classified on a spectrum of low potency to high potency, where potency referred to the ability of the drug to bind to dopamine receptors, and not to the effectiveness of the drug.
=== Drugs === The anti-diabetic medication pioglitazone was shown in a mouse model of ALD to be effective at treating the metabolic effects of ALD, including metabolic failure and increased oxidative stress. Pioglitazone was also shown to prevent axonal degeneration and increase mitochondria levels, as well as stop the progression of locomotor decline in ALD model mice. Subsequently, the experimental drug leriglitazone has been developed as a more brain penetrant metabolite of pioglitazone. As of 2023, leriglitazone is in phase 2/3 clinical trials for adult and childhood cALD in the USA and the EU, and has completed a clinical trial for AMN.
On May 20, 2025, U.S. president Donald Trump announced plans for a new space-based missile defense system called the "Golden Dome" intended to shield the United States from long-range and hypersonic missiles. The name alludes to Israel's Iron Dome but the system is planned to be orders of magnitude broader in scope. Technical details and deployment plans were not released. Trump said the project would be completed within three years and cost about $175 billion, a feasibility, timeline, and price estimate that were quickly and widely disputed. The Congressional Budget Office estimated that it could cost between $161 billion and $542 billion over 20 years, while Republican senators involved in the program predicted it would ultimately cost "trillions of dollars." In April 2025 the Director, Operational Test and Evaluation (DOT&E) determined that the Golden Dome fell under its oversight, as they are required by law to analyze testing plans for defense programs with procurements above $3 billion. Days later, Elon Musk's Department of Government Efficiency (DOGE) investigated the office and slashed its resources. A defense official told CNN that they believed DOGE wanted to prevent DOT&E conducting independent oversight of the Golden Dome. In May 2025, 42 members of US Congress formally asked the DoD Inspector General to review Elon Musk’s involvement in the Golden Dome.
Sources: en.wikipedia.org
26 October In two studies, scientists report findings about the role of epigenetics – which is shaped during lifetime – in colorectal cancer, including that it is a major component of how an individual tumor varies and findings about its influences on the accumulation of DNA mutations and cancer phenotypes. At the 30th anniversary of the World Scientists' Warning to Humanity, scientists conclude that "We are now at 'code red' on planet Earth", facing a climate emergency, warning citizens and world leaders to take necessary actions with information about tracked "recent climate-related disasters, assess[ed] planetary vital signs, and [...] policy recommendations". A study concludes that cosmic radiation events in the tree-ring radiocarbon record called "Miyake events", don't appear to be caused by the solar cycle (i.e. solar flares) as thought previously and have extended durations. They occurred every ~1,000 years on average and may threaten global technologies this century. A magnetical guidance system with engineered bacterial microbots (see also 22 September above) for 'precision targeting' is demonstrated to be effective for fighting cancer in mice. 31 October Multiple traces of monkeypox are detected in non-sewered wastewater with sparse sampling from a densely populated metropolitan area in Asia. A new record for the longest-frozen embryos to ever result in a live birth is reported in the United States, with twins born after storage for 30 years.
Provides straightforward information about effects arising from individual compounds in complex or natural samples separated in parallel. Combines chromatographic separation with effect-directed detection using enzymatic or biological assays. Helps to select important compounds from a sample for further characterization using high-resolution mass spectrometry. Offers unique benefits such as super-hyphenation, minimum sample preparation requirements, detection of multi-modulating compounds, and distinguishing agonistic versus antagonistic effects.
I am so relieved. I can't even believe it. Exactly two years ago I was forced to have as much security as possible due to threats. Ever since then, i have never walked alone in the streets. It was heavy. Fortunately, I could still do my job. It was a difficult time in my career. When you hear such news, it is an incredible relief. In 2017, writer Raf Sauviller published his book Borgerokko Maffia, which was distributed to many libraries across Flanders (Belgium) and the Netherlands. In his book, he discusses the corruption that takes place in the Port of Antwerp amongst police officers and Customs controls. According to research which was carried out in 2018, the municipality of Borgerhout, Antwerp, had an illegal economy which was larger than the regular economy due to the influx of funds by the Moroccan mafia. During an interview by the newspaper De Morgen on the context of this book, the mayor of Antwerp, Bart De Wever, admitted that there were many difficulties on intercepting the main commanders of the Moroccan mafia in Antwerp. He also stated:
Sources: en.wikipedia.org
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.
Melanotan-1, also called afamelanotide, is a linear analogue with greater selectivity for MC1R and has received approval in some jurisdictions for a specific photosensitivity disorder. Melanotan-2 is cyclic, less selective, and reaches central receptors more readily. The two are often confused in online discussion despite different pharmacology and regulatory status.
Alpha-MSH is an endogenous tridecapeptide derived from pro-opiomelanocortin. Melanotan-2 reproduces its core receptor-binding sequence inside a shortened, stabilised ring. The result is a molecule with a longer effective half-life and higher potency than the parent hormone.
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.