If you have been reading about MC1R 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 2025-10-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms differ |
| Molecular weight | Approximately 1024 g/mol | Calculated for the free base |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and polar solvents | Poorly soluble in non-polar solvents |
| Typical storage | -20 degrees Celsius, dry, protected from light | Refers to the solid form |
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.
Additionally, cortisol facilitates the activation of glycogen phosphorylase, which is necessary for adrenaline to have an effect on glycogenolysis. Paradoxically, cortisol promotes both gluconeogenesis (biosynthesis of glucose molecules) in the liver and glycogenesis (polymerization of glucose molecules into glycogen); cortisol is thus better thought of as stimulating glucose/glycogen turnover in the liver. This is in contrast to cortisol's effect in the skeletal muscle where glycogenolysis is promoted indirectly through catecholamines. In this way, cortisol and catecholamines work synergistically to promote the breakdown of muscle glycogen into glucose for use in the muscle tissue.
=== Cognitive effects === The short-term use of benzodiazepines adversely affects multiple areas of cognition, the most notable being that it interferes with the formation and consolidation of memories of new material and may induce complete anterograde amnesia. However, researchers hold contrary opinions regarding the effects of long-term administration. One view is that many of the short-term effects continue into the long-term and may worsen, and are not resolved after stopping benzodiazepine usage. Another view maintains that cognitive deficits in chronic benzodiazepine users occur only for a short period after the dose, or that the anxiety disorder is the cause of these deficits. While the definitive studies are lacking, the former view received support from a 2004 meta-analysis of 13 small studies. This meta-analysis found that long-term use of benzodiazepines was associated with moderate to large adverse effects on all areas of cognition, with visuospatial memory being the most commonly detected impairment. Some of the other impairments reported were decreased IQ, visiomotor coordination, information processing, verbal learning, and concentration. The authors of the meta-analysis and a later reviewer noted that the applicability of this meta-analysis is limited because the subjects were taken mostly from withdrawal clinics; the coexisting drug, alcohol use, and psychiatric disorders were not defined; and several of the included studies conducted the cognitive measurements during the withdrawal period.
== Mechanism of action == Tedizolid phosphate (TR-701) is a prodrug activated by plasma or intestinal phosphatases to tedizolid (TR-700) following administration of the drug either orally or intravenously. Once activated, tedizolid exerts its bacteriostatic microbial activity through inhibition of protein synthesis by binding to the 50S ribosomal subunit (on the acceptor site) of the bacteria.
Meanwhile, a Chilean squadron set sail on November 15, 1824, to help in the blockade of Callao, commanded by Vice Admiral Blanco Encalada, who had learned of the intentions of Bolívar and other Lima authorities to annex the southern archipelago due to their old ties. with Peru, when he landed with his fleet in Quilca on January 6, 1825, so in June he decided to return to Valparaíso with the Chilean fleet to report that the island should be conquered as soon as possible, even if that was to the detriment of the interests Peruvians.
Sources: en.wikipedia.org
==== Insomnia ==== Tiagabine is used in the treatment of insomnia. Lower doses than those used in epilepsy, in the range of 2 to 16 mg, are used to treat insomnia. The drug has been found to enhance slow wave sleep (SWS) in the context of insomnia. Its effects on SWS are dose dependent, with a 2- to 4-fold increase in SWS at doses of 8 to 16 mg but mixed findings for a dose of 4 mg. Findings are mixed in terms of the influence of tiagabine on sleep onset, sleep duration, nighttime awakenings, self-reported sleep ratings, and ratings of restorative or refreshing sleep. Tiagabine has been found to decrease the cognitive impairment and high cortisol levels caused by sleep restriction, with this being related to the drug's SWS improvement. On the other hand, despite increasing SWS, tiagabine did not improve memory consolidation. The effects of tiagabine on sleep, for instance primarily increasing SWS, resemble those of gaboxadol and muscimol but are very different from those of conventional GABAA receptor positive allosteric modulators like benzodiazepines and Z drugs. The American Academy of Sleep Medicine's 2017 clinical practice guidelines recommended against the use of tiagabine in the treatment of insomnia due to limited effectiveness and very low quality of evidence.
== Adverse effects == Depolarizing drug Succinylcholine: Succinylcholine presents several undesirable side effects which affect its application as it interacts with both muscarinic and nicotinic receptors, due to its acetylcholine-mimicking properties. Firstly, hyperkalemia is the most seen adverse effect of succinylcholine due to its stimulatory effect of the drug on skeletal muscles. This results in an increase in serum potassium levels as high as 0.5 mEq/L. This increase is clinically insignificant in normal patients but can be detrimental for patients with predisposed hyperkalemia caused by up-regulation of post-junctional acetylcholine receptors. Therefore, succinylcholine use is contraindicated for this category of patients. Further consideration is also required for patients with chronically elevated potassium or traumatic injuries, as there is a high probability of acute hyperkalemia which can lead to dysrhythmia or death. Secondly, succinylcholine causes the activation of muscarinic receptors in the SA node, causing bradycardia. This effect is especially highlighted in use with patients with high vagal tone (traumatic or young patients). In adults with a normal vagal tone, bradycardia has only been reported on repeated incremental dosages of succinylcholine. Anticholinergic drugs such as atropine and glycopyrrolate can be used as secondary therapy in treating or prophylaxis of bradycardia.
SPINA-GBeta is a calculated biomarker for pancreatic beta cell function. It represents the maximum amount of insulin that beta cells can produce per time-unit (e.g. in one second). The method of calculation is based on a time-discrete nonlinear feedback model of insulin-glucose homeostasis that is rooted in the MiMe-NoCoDI modeling platform for endocrine systems.
==== Foreign body reactions ==== Foreign body reactions appear as red or red and white, possibly painful longstanding lesions similar to desquamative gingivitis, or be granulomatous or lichenoid in nature. Tiny particles of dental materials (e.g. abrasive polishing pastes) may become impregnated in the gingival tissues and trigger a chronic inflammatory cell response.
=== Gas === Although nitrogen is non-toxic, when released into an enclosed space it can displace oxygen, and therefore presents an asphyxiation hazard. This may happen with few warning symptoms, since the human carotid body is a relatively poor and slow low-oxygen (hypoxia) sensing system. An example occurred shortly before the launch of the first Space Shuttle mission on March 19, 1981, when two technicians died from asphyxiation after they walked into a space located in the Space Shuttle's mobile launcher platform that was pressurised with pure nitrogen as a precaution against fire. When inhaled at high partial pressures (more than about 4 bar, encountered at depths below about 30 m in scuba diving), nitrogen is an anaesthetic agent, causing nitrogen narcosis, a temporary state of mental impairment similar to nitrous oxide intoxication. Nitrogen dissolves in the blood and body fats. Rapid decompression (as when divers ascend too quickly or astronauts decompress too quickly from cabin pressure to spacesuit pressure) can lead to a potentially fatal condition called decompression sickness (formerly known as caisson sickness or the bends), when nitrogen bubbles form in the bloodstream, nerves, joints, and other sensitive or vital areas. Bubbles from other "inert" gases (gases other than carbon dioxide and oxygen) cause the same effects, so replacement of nitrogen in breathing gases may prevent nitrogen narcosis, but does not prevent decompression sickness.
Sources: en.wikipedia.org
In cancer, there are substantial metabolic derangements that occur to ensure the proliferation of tumor cells, and consequently metabolites can accumulate which serve to facilitate tumorigenesis, dubbed oncometabolites. Among the best characterized oncometabolites is 2-hydroxyglutarate which is produced through a heterozygous gain-of-function mutation (specifically a neomorphic one) in isocitrate dehydrogenase (IDH) (which under normal circumstances catalyzes the oxidation of isocitrate to oxalosuccinate, which then spontaneously decarboxylates to alpha-ketoglutarate, as discussed above; in this case an additional reduction step occurs after the formation of alpha-ketoglutarate via NADPH to yield 2-hydroxyglutarate), and hence IDH is considered an oncogene. Under physiological conditions, 2-hydroxyglutarate is a minor product of several metabolic pathways as an error but readily converted to alpha-ketoglutarate via hydroxyglutarate dehydrogenase enzymes (L2HGDH and D2HGDH) but does not have a known physiologic role in mammalian cells; of note, in cancer, 2-hydroxyglutarate is likely a terminal metabolite as isotope labelling experiments of colorectal cancer cell lines show that its conversion back to alpha-ketoglutarate is too low to measure. In cancer, 2-hydroxyglutarate serves as a competitive inhibitor for a number of enzymes that facilitate reactions via alpha-ketoglutarate in alpha-ketoglutarate-dependent dioxygenases. This mutation results in several important changes to the metabolism of the cell.
Following the invasion and annexation of Kuwait by Iraq, on September 25, 1990, the Italian Government sent eight multirole fighter bombers Tornado IDS (plus two spare) in the Persian Gulf, belonging to the 6º, 36º and 50º Stormo, which were deployed at the Al Dhafra Air Base, near Abu Dhabi, in the United Arab Emirates. During the 42 days of war, Italian fighters made 226 sorties for a total of 589 flight hours. The Italian Air Force lost one aircraft in the Gulf War. The use of Italian aircraft as part of the Desert Storm operation represented the first operational employment in combat missions of Italian Air Force aircraft since the end of World War II.
Hyperphosphorylation of the tau protein (tau inclusions, pTau) can result in the self-assembly of tangles of paired helical filaments and straight filaments, which are involved in the pathogenesis of Alzheimer's disease, frontotemporal dementia and other tauopathies. All of the six tau isoforms are present in an often hyperphosphorylated state in paired helical filaments in the Alzheimer's disease brain. In other neurodegenerative diseases, the deposition of aggregates enriched in certain tau isoforms has been reported. When misfolded, this otherwise very soluble protein can form extremely insoluble aggregates that contribute to a number of neurodegenerative diseases. Tau protein has a direct effect on the breakdown of a living cell caused by tangles that form and block nerve synapses. Gender-specific tau gene expression across different regions of the human brain has recently been implicated in gender differences in the manifestations and risk for tauopathies. Some aspects of how the disease functions also suggest that it has some similarities to prion proteins.
DMT is used either in pure form or in the form of naturally sourced materials. It occurs naturally in many plants, among the more notable species including Psychotria viridis, Mimosa tenuiflora, and Diplopterys cabrerana. The drug is often present alongside its close analogues 5-MeO-DMT (mebufotenin) and bufotenin (5-HO-DMT). It has widely been used as an entheogen or for shamanistic purposes in Central and South America, for instance among Amazonian peoples. This includes as the traditional beverage ayahuasca and other forms. Ayahuasca is a boiled mixture of different plants, including a DMT-containing plant like Psychotria viridis, Psychotria carthagenensis, or Diplopterys cabrerana together with another plant known as Banisteriopsis caapi. A variety of different recipes may be used to make the brew. DMT is usually the main active constituent of ayahuasca, but ayahuasca is sometimes also brewed with plants that do not contain DMT. The drug is also found as a minor alkaloid in hallucinogenic snuffs such as those made from Virola or Anadenanthera plant materials but in which the major active drugs are instead 5-MeO-DMT and/or bufotenin. In addition to its use as an entheogen, DMT is used recreationally. DMT is not orally active on its own and is given by parenteral administration, such as smoking, intramuscular injection, subcutaneous injection, or intravenous injection. Other routes like intranasal, buccal, or rectal administration have also been tried but were all reported to be inactive.
Sources: en.wikipedia.org
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.
Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.
Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.
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.