afamelanotide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-06-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
| 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 |
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.
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.
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.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
== Diagnosis == Echocardiography is the preferred screening test in the diagnosis of PAH as it accurately estimates pulmonary pressures. Other causes of pulmonary hypertension, such as left heart disease (WHO group 2), pulmonary hypertension due to lung disease (such as COPD)(WHO group 3) and pulmonary hypertension due to chronic blood clots in the pulmonary arteries (WHO group 4) need to be ruled out. Some tests which are commonly used include a CT scan of the chest, ventilation perfusion scan or a CT angiography (to rule out pulmonary hypertension due to chronic blood clots), pulmonary function test, and a cardiac MRI. Cardiac MRI is the preferred test to evaluate right ventricular structure and function in PAH. Pulmonary function testing in PAH may show an obstructive or restrictive defect, and the diffusion capacity of carbon monoxide (used as a surrogate for gas exchange in the alveoli) is reduced. A sleep study helps to rule out sleep disordered breathing, such as sleep apnea, which may contribute to PAH. The N-terminal prohormone of brain natriuretic peptide (NT pro-BNP) may be monitored in those with PAH and is prognostic. A right heart catheterization to measure right heart pressure is required for the diagnosis of PAH.
In July 1974, Fripp, Bruford, and Wetton began recording Red. Before recording began, Fripp, now increasingly disillusioned with the music industry, turned his attention to the works of English mystic John G. Bennett and had a spiritual experience in which "the top of my head blew off". Most of the album had been developed during live improvisations before Fripp "withdrew his opinion", leaving his bandmates to direct the sessions. The album contains one live track, "Providence", recorded on 30 June 1974 in Providence, Rhode Island with Cross on violin. Several guest musicians, including former members Ian McDonald and Mel Collins on saxophones, contributed to the album. Released on 6 October 1974, Red went to No. 45 in the UK and No. 66 in the US. AllMusic later called it "an impressive achievement" for a group about to disband, with "intensely dynamic" musical chemistry between the band members. Two months before the release of Red, King Crimson's future looked bright, with talks regarding the possibility of McDonald rejoining the group. However, Fripp wished not to tour as he felt increasingly disenchanted by the group and the music industry. He also felt the world was going to drastically change by 1981 and that he had to prepare for it. Despite a band meeting while touring the US in which Fripp expressed a desire to end the band, the group did not formally disband until 25 September 1974; the following month Fripp announced in an interview with Trouser Press magazine that King Crimson had "ceased to exist" and was "completely over for ever and ever".
2 CaSO4 + 2 SiO2 + C → 2 CaSiO3 + 2 SO2 + CO2 Until the 1970s commercial quantities of sulfuric acid and cement were produced by this process in Whitehaven, England. Upon being mixed with shale or marl, and roasted, the sulfate liberated sulfur dioxide gas, used in sulfuric acid production, the reaction also produced calcium silicate, a precursor in cement production. On a laboratory scale, the action of hot concentrated sulfuric acid on copper turnings produces sulfur dioxide.
==== Analysis of Nidogen-1 interacting with Laminin γ1 ==== Laminin's are non-collagenous proteins found in basement membranes and form networks through non-covalent self-interactions. Nidogens (also known as entactins) are sulfated monomeric glycoproteins that are ubiquitously present in basement membranes of higher organisms. Nidogens help with the formation of the basement. With both laminins and nidogens present, both interact with each other to have a stoichiometry relationship of 1:1 in a complex. In order to study the short arm of laminin γ1, photo methionine introduced both to nidogen-1, laminin γ1 LEb2-4, and laminin γ1 short arm to see if this photo-cross linking method could map out the structure. MS/MS analysis was done before cross-linking to find only 13-25% of methionine's had been incorporated, but once UV-A-induced or another cross-linker, BS2G-mediated cross-linked (a homobifunctional cross-linker), the percentage of photo-methionine's had increased to 35%. Both cross-linkers had shown extra structural insight both computationally and experimentally to help with understanding the functions.
Sources: en.wikipedia.org
== Bibliography == Golub, A. M. (1971). Общая и неорганическая химия (General and Inorganic Chemistry). Vol. 2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8. Myasoedov, B. (1972). Analytical chemistry of transplutonium elements. Moscow: Nauka. ISBN 978-0-470-62715-0.
To increase the potency they attached a phenolic group to the aromatic ring, N-methyl-trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine. That structure was used to design and develop other opioid receptors antagonists such as alvimopan. Alvimopan was approved later in 2008 for in-hospital use to increase the gastrointestinal function following a partial large or small bowel resection with primary anastomosis. Naloxegol was approved in September 2014 and naldemedine in March 2017, both for the treatment of OIC in adult patients with chronic cancer.
A liver biopsy (tissue examination) is the only test widely accepted (gold standard) as definitively diagnosing and distinguishing MASLD and MASH from other forms of liver disease. It can be used to assess the severity of inflammation and resultant fibrosis. However, since most people affected by MASLD are likely to be asymptomatic, liver biopsy presents too high a risk for routine diagnosis, so other methods are preferred, such as liver ultrasonography or liver MRI. For young people, guidelines recommend liver ultrasonography, but biopsy remains the best evidence. Liver biopsy is also the gold standard to detect hepatic fibrosis and assess its progression. Routine liver function blood tests are not sensitive enough to detect MASLD, and biopsy is the only procedure that can reliably differentiate MASLD from MASH. There are several liver biopsy techniques available to obtain liver tissue. Percutaneous liver biopsy remains the most common practice. Biopsies can also be performed via the transvenous route, either during surgery or by laparoscopy, especially for people with contraindications to a percutaneous approach. The liver biopsy can also be image-guided, in real-time or not, which is recommended for some clinical situations, such as people with known liver lesions, previous intra-abdominal surgery who may have adhesions, a small liver that is difficult to percuss, people with obesity, and people with evident ascites.
== Incidence == Numerous Laron syndrome patients are found in Israel among the country's diverse Jewish population composed of Jews from around the world, as well as patients outside Israel originally from communities of the Jewish diaspora, such as Egypt and Iraq. The original "Israeli cohort" of patients referred to Zvi Laron and colleagues beginning in 1958 consisted of 64 patients as of 2009, including 4 deceased patients. The countries of origin of these patients include Israel, Palestine, Jordan, Lebanon, Iran, Malta, Italy, Argentina, Ecuador, and Peru. A disproportionate number of people with the condition are found in remote villages in the Loja province of Ecuador. These individuals are descended from colonial-era Jewish-origin New Christian conversos (Sephardi Jews who themselves, or whose forebears, had been compelled to convert to Catholicism back in Spain) who had covertly migrated to Ecuador during the Spanish Conquest despite the Spanish Crown's prohibition of their emigration to its colonies and territories as a result of the Inquisition. Other patients include people of other Semitic non-Jewish origins, including from Saudi Arabia, Japan, and China.
The Ural Cossack Host was formed from the Ural Cossacks, who had settled along the Ural River. Their alternative name, Yaik Cossacks, comes from the river's former name, changed by the government after Pugachev's Rebellion of 1773–1775. The Ural Cossacks spoke Russian, and identified as having primarily Russian ancestry, but also incorporated many Tatars into their ranks. In 1577, twenty years after Moscow had conquered the Volga from Kazan to Astrakhan, the government sent troops to disperse pirates and raiders along the Volga. Among them was Yermak Timofeyevich. Some escaped to flee southeast to the Ural River, where they joined the Yaik Cossacks. In 1580, they captured Saraichik. By 1591, they were fighting on behalf of the government in Moscow. Over the next century, they were officially recognized by the imperial government.
Sources: en.wikipedia.org
Sarcoidosis Granulomatous lung diseases Tuberculosis Fungal infections (e.g., histoplasmosis) Granulomatosis with polyangiitis Idiopathic pulmonary fibrosis Hypersensitivity pneumonitis Asthma Diagnosis of berylliosis is based on history of beryllium exposures, documented beryllium sensitivity, and granulomatous inflammation on lung biopsy. Given the invasive nature of a lung biopsy, diagnosis can also be based on clinical history consistent with berylliosis, abnormal chest x-ray or CT scan findings, and abnormalities in pulmonary function tests. The radiologic and pathologic features of berylliosis are very similar to sarcoidosis. Due to the strong clinical and histopathological resemblance of sarcoidosis and berylliosis, patients are sometimes misdiagnosed with sarcoidosis until the history of exposure to beryllium is elicited and beryllium hypersensitivity demonstrated with specific testing. Some studies suggest that up to 6% of all cases of sarcoidosis are actually berylliosis. The beryllium lymphocyte proliferation test (BeLPT) is the standard way of determining sensitivity to beryllium. The test is performed by acquiring either peripheral blood or fluid from a bronchial alveolar lavage, and lymphocytes are cultured with beryllium sulfate. Cells are then counted and those with elevated number of cells are considered abnormal. Those exposed persons with two abnormal BeLPT tested with peripheral blood, or one abnormal and one borderline result, are considered beryllium sensitized.
Students who received the copies flagged blurred answer sheets, missing pages, and, in some cases, received another student’s answer book. The controversy intensified significantly when a Delhi-based student, Vedant Shrivastava, shared evidence on social media that his Physics answer sheet uploaded under his roll number featured different handwriting and belonged to someone else. Soon after, he became the target of trolling and abusive comments online. Some called him "anti-national", while others labelled him "Pakistani". Among those who initially called the student a "Pakistani" was Doordarshan News journalist Ashok Shrivastav. He later apologised, but his remarks sparked massive backlash online. After the complaint went viral, CBSE officially acknowledged the technical error, issued the correct answer sheet to the student, and promised to rectify his result. The board faced further backlash following allegations that it attempted to manage public perception rather than addressing structural evaluation errors. Reports surfaced indicating that CBSE had allegedly circulated a communication toolkit to schools and forced school principals to flood social media with coordinated videos and posts defending its controversial On-Screen Marking System (OSM). Independent observers and online watchdogs noted a coordinated pattern where multiple school principals and institutions published videos using identical phrasing to praise the digital evaluation system.
Acetylcysteine was patented in 1960 as a mucolytic agent. In the 1960s, it was used for managing the mucous symptoms of illnesses including cystic fibrosis, asthma, and chronic bronchitis, as well as other uses, such as a chelating agent in gold therapy. In the late 1960s, the popularity of acetaminophen led to an increase in overdose hepatotoxicity. In 1974, it was discovered that the mechanism was oxidation via cytochrome P450, and administering glutathione-like reducing agents, such as IV cysteine, or oral methionine, were successful in preventing hepatotoxicity. In the US, the then-common formulation of NAC was not certified as pyrogen-free, and thus not approved for IV use. The producer, Mead Johnson, was unwilling to take the expense of certification. In 1977, there was the first case report of oral NAC preventing acetaminophen overdose hepatoxicity in the US. Meanwhile, in the UK, IV NAC (trade name, Parvolex) was found to be more effective and has less side effect than IV cysteamine (associated with a "general feeling of misery") or methionine. There was a dispute concerning whether the oral NAC and the IV NAC is more effective, with the conclusion reached in 1999, that they are roughly equally effective. Another producer finally obtained approval for the IV form of NAC (trade name, Acetadote) in the US in 2004. Amazon removed acetylcysteine for sale in the US in 2021, due to claims by the Food and Drug Administration (FDA) of it being classified as a drug rather than a supplement.
==== Recreational use ==== A 1989 article in the European Journal of Clinical Pharmacology reports that benzodiazepines accounted for 52% of prescription forgeries in Sweden, suggesting that benzodiazepines were a major prescription drug class of abuse. Nitrazepam accounted for 13% of forged prescriptions, and accounted for 44% of forgeries specifically for benzodiazepines while flunitrazepam, diazepam, and oxazepam accounted for the majority of the rest of benzodiazepine forgeries. Prescription forgeries for other benzodiazepines marketed in Sweden (alprazolam, clonazepam, lorazepam, clobazam, and bromazepam) were negligible. When calculated in relation to utilization, the narcotic analgesics codeine, pentazocine, and ketobemidone were at the top of the list for the highest number of overall prescription forgeries, suggesting a higher abuse potential of these drugs. In neighboring Finland, temazepam accounts for roughly 40–50% benzodiazepine prescription forgeries annually, while flunitrazepam accounts for approximately ~15% of benzodiazepine prescription forgeries. Flunitrazepam and other sedative hypnotic drugs are detected frequently in cases of people suspected of driving under the influence of drugs. Other benzodiazepines and nonbenzodiazepines (anxiolytic or hypnotic) such as zolpidem and zopiclone (as well as cyclopyrrolones, imidazopyridines, and pyrazolopyrimidines) are also found in high numbers of suspected drugged drivers.
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.
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.