The short version of afamelanotide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-28 and is reviewed periodically as new material appears.
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.
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.
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.
| 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 |
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.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
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.
In 2021, the best preserved specimen of a dinosaur's cloacal vent exterior was described for Psittacosaurus, demonstrating lateral swellings similar to crocodylian musk glands used in social displays by both sexes and pigmented regions which could also reflect a signalling function. However, this specimen on its own does not offer enough information to determine whether this dinosaur had sexual signalling functions; it only supports the possibility. Cloacal visual signalling can occur in either males or females in living birds, making it unlikely to be useful to determine sex for extinct dinosaurs.
. It is unitless. A "high-resolution" mass analyzer typically has resolution >1 million. Concretely, that means it can resolve two peaks at ~1 kDa, differing by just ~1 mDa. The absolute accuracy is the ratio of the m/z measurement error to the true m/z. It is defined as
Mary was a first-century Jewish woman of Nazareth, the wife of Joseph and the mother of Jesus. She is a central figure of Christianity, venerated under various titles such as virgin or queen, many of them mentioned in the Litany of Loreto. The Eastern and Oriental Orthodox, Church of the East, Catholic, Anglican, and Lutheran churches believe that Mary, as mother of Jesus, is the Mother of God. Other Protestant views on Mary vary, with some holding her to have lesser status. Christian Marian perspectives include a great deal of diversity. While some Christians such as Catholics and Eastern Orthodox have well established Marian traditions, Protestants at large pay scant attention to Mariological themes. Catholic, Eastern Orthodox, Oriental Orthodox, Anglican, and Lutherans venerate the Virgin Mary. This veneration especially takes the form of prayer for intercession with her Son, Jesus Christ. Additionally, it includes composing poems and songs in Mary's honor, painting icons or carving statues of her, and conferring titles on Mary that reflect her position among the saints. The Druze faith holds the Virgin Mary, known as Sayyida Maryam, in high regard. Although the Druze religion is distinct from mainstream Islam and Christianity, it incorporates elements from both and honors many of their figures, including the Virgin Mary. The Druze revere Mary as a holy and pure figure, embodying virtue and piety. She is respected not only for her role as the mother of Messiah Jesus but also for her spiritual purity and dedication to God.
In consultation with a physician, usage of herbal remedies should be clarified, as some herbal remedies have the potential to cause adverse drug interactions when used in combination with various prescription and over-the-counter pharmaceuticals, just as a customer should inform a herbalist of their consumption of actual prescription and other medication. For example, dangerously low blood pressure may result from the combination of a herbal remedy that lowers blood pressure together with prescription medicine that has the same effect. Some herbs may amplify the effects of anticoagulants. Certain herbs as well as common fruit interfere with cytochrome P450, an enzyme critical to much drug metabolism. In a 2018 study, the FDA identified active pharmaceutical additives in over 700 analyzed dietary supplements sold as "herbal", "natural" or "traditional". The undisclosed additives included "unapproved antidepressants and designer steroids", as well as prescription drugs, such as sildenafil or sibutramine.
Based on crystallography data of homologous NADP-dependent malic enzymes of mammalian origin, a 3D model for C4 pathway NADP-ME in plants has been developed, identifying the key residues involved in substrate-binding or catalysis. Dinucleotide binding involves two glycine-rich GXGXXG motifs, a hydrophobic groove involving at least six amino acid residues, and a negatively charged residue at the end of the βB-strand. The primary sequence of the first motif, 240GLGDLG245, is a consensus marker for phosphate binding, evidencing involvement with NADP binding, while the other glycine rich motif adopts a classical Rossmann fold—also a typical marker for NADP cofactor binding. Mutagenesis experiments in maize NADP-ME have supported the current model. Valine substitution for glycine in either motif region rendered the enzyme completely inactive while spectral analysis indicated no major changes from wild-type form. The data is suggestive of direct impairment at a key residue involved in binding or catalysis rather than an inter-domain residue influencing conformational stability. Additionally, a key arginine residue at site 237 has been shown to interact both with malate and NADP+ substrates, forming key favorable electrostatic interactions to the negatively charged carboxylic-acid and phosphate group respectively. Elucidation of whether the residue plays a role in substrate binding or substrate positioning for catalysis has yet to be determined.
Sources: en.wikipedia.org
But I realised that wasn't the truth." Upon Ceaușescu's return from Iran on the evening of 20 December, the situation became even more tense, and he gave a televised speech from the TV studio inside the Central Committee Building (CC Building) in which he spoke about the events at Timișoara in terms of an "interference of foreign forces in Romania's internal affairs" and an "external aggression on Romania's sovereignty." The country, which had no information about the Timișoara events from the national media, heard about the Timișoara revolt from Western radio stations like Voice of America and Radio Free Europe, and by word of mouth. A mass meeting was staged for the next day, 21 December, which, according to the official media, was presented as a "spontaneous movement of support for Ceaușescu," emulating the 1968 meeting in which Ceaușescu had spoken against the invasion of Czechoslovakia by Warsaw Pact forces.
=== Conflict === Channel conflict can arise when one intermediary's actions prevent another intermediary from achieving their objectives. Vertical channel conflict occurs between the levels within a channel, and horizontal channel conflict occurs between intermediaries at the same level within a channel. Channel conflict is a perennial problem. There are risks that a powerful channel member may coordinate the interests of the channel for personal gain. Territories are often seen as a source of conflict, sometimes because boundaries are only loosely defined.
Recombinant antibodies are monoclonal antibodies generated in vitro using synthetic genes. Recombinant antibody technology involves recovering the antibody genes from the source cells, amplifying and cloning the genes into an appropriate vector, introducing the vector into a host, and achieving expression of adequate amounts of functional antibody. Recombinant antibodies can be cloned from any species of antibody-producing animal, if the appropriate oligonucleotide primers or hybridization probes are available. The ability to manipulate the antibody genes make it possible to generate new antibodies and antibody fragments, such as Fab fragments and scFv in vitro. This can be done at the level of the whole combining site by making new combinations of H and L chains. It can also be done by mutating individual CDRs. Display libraries, commonly expressed in phage or yeast, can be analysed to select for desirable characteristics arising from such changes in antibody sequence.
==== 1988 Seoul Olympics ==== A famous case of AAS use in a competition was Canadian Ben Johnson's victory in the 100 m at the 1988 Summer Olympics. He subsequently failed the drug test when stanozolol was found in his urine. He later admitted to using the steroid as well as Dianabol, testosterone, Furazabol, and human growth hormone amongst other things. Johnson was stripped of his gold medal as well as his world-record performance. Carl Lewis was then promoted one place to take the Olympic gold title. Lewis had also run under the current world record time and was therefore recognized as the new record holder. Johnson was not the only participant whose success was questioned: Lewis had tested positive at the Olympic Trials for pseudoephedrine, ephedrine and phenylpropanolamine. Lewis defended himself, claiming that he had accidentally consumed the banned substances. After the supplements that he had taken were analyzed to prove his claims, the USOC accepted his claim of inadvertent use, since a dietary supplement he ingested was found to contain "Ma huang", the Chinese name for Ephedra (ephedrine is known to help weight loss). Fellow Santa Monica Track Club teammates Joe DeLoach and Floyd Heard were also found to have the same banned stimulants in their systems, and were cleared to compete for the same reason. The highest level of the stimulants Lewis recorded was 6 ppm, which was regarded as a positive test in 1988.
Sources: en.wikipedia.org
If she can only cook as well as Honeywell can compute. Her souffles are supreme, her meal planning a challenge? She's what the Honeywell people had in mind when they devised our Kitchen Computer. She'll learn to program it with a cross-reference to her favorite recipes by N-M's own Helen Corbitt. Then by simply pushing a few buttons obtain a complete menu organized around the entree. And if she pales at reckoning her lunch tabs, she can program it to balance the family checkbook. 84A 10,600.00 complete with two week programming course. 84B Fed with Corbitt data: the original Helen Corbitt cookbook with over 1,000 recipes 5.00 (.75) 84C Her Potluck, 375 of our famed Zodiac restaurant's best kept secret recipes 3.95 (.75) Corbitt Epicure 84D Her Tabard Apron, one-size, ours alone by Clairdon House, multi-pastel provincial cotton 26.00 (.90) Trophy Room
RN=C=NR ↔ RN+≡C-N−R ↔ RN−-C≡N+R The N=C=N core is relatively linear and the C-N=C angles approach 120°. In the case of C(NCHPh2)2, the central N=C=N angle is 170° and the C-N=C angles are within 1° of 126°. The C=N distances are short, nearly 120 pm, as is characteristic of double bonds. Carbodiimides are chiral, possessing C2-symmetry and therefore axial chirality. However, due to the low energy barrier to the molecule rotating and thereby converting quickly between its isomers, the actual isolation of one optical isomer of a carbodiimide is extremely difficult. It has been demonstrated at least once, in the case of conformationally restricted cyclic carbodiimides; though there are other reports of one-handed axially chiral carbodiimides, their validity has since been called into question on experimental and computational grounds. The parent compound, methanediimine, (HN=C=NH), is a tautomer of cyanamide.
The most common side effects of oxycodone include delayed gastric emptying, euphoria, anxiolysis (a reduction in anxiety), feelings of relaxation, and respiratory depression. Common side effects of oxycodone include constipation (23%), nausea (23%), vomiting (12%), drowsiness (23%), dizziness (13%), itching (13%), dry mouth (6%), and sweating (5%). Less common side effects (experienced by less than 5% of patients) include loss of appetite, nervousness, abdominal pain, diarrhea, urinary retention, dyspnea, and hiccups. Most side effects generally become less intense over time, although issues related to constipation are likely to continue for the duration of use. Chronic use of oxycodone and the associated constipation issues can become severe, and have been implicated in life-threatening bowel perforations. A number of specific medications including naloxegol have been developed to address opioid induced constipation. Oxycodone in combination with naloxone in managed-release tablets has been formulated to both deter abuse and reduce opioid-induced constipation.
Hepatotoxicity: elevated transaminases Nephrotoxicity: acute kidney injury from rhabdomyolysis Also, myopathy and rhabdomyolysis have been reported in patients simultaneously taking statins, but whether this is due entirely to the statin or whether daptomycin potentiates this effect is unknown. Due to the limited data available, the manufacturer recommends that statins be temporarily discontinued while the patient is receiving daptomycin therapy. Creatine kinase levels are usually checked regularly while individuals undergo daptomycin therapy. In July 2010, the FDA issued a warning that daptomycin could cause life-threatening eosinophilic pneumonia. The FDA said it had identified seven confirmed cases of eosinophilic pneumonia between 2004 and 2010 and an additional 36 possible cases. The seven confirmed cases were all older than 60 and symptoms appeared within two weeks of initiation of therapy.
Antimicrobial resistance means that a microorganism is resistant to an antimicrobial drug that was once able to treat an infection by that microorganism. Resistance is a property of the microbe, not a person or other organism infected by a microbe. All types of microbes can develop drug resistance. Thus, there are antibiotic, antifungal, antiviral and antiparasitic resistance. Antibiotic resistance is a subset of antimicrobial resistance. This more specific resistance is linked to bacteria and thus broken down into two further subsets, microbiological and clinical. Microbiological resistance is the most common and occurs from genes, mutated or inherited, that allow the bacteria to resist the mechanism to kill the microbe associated with certain antibiotics. Clinical resistance is shown through the failure of many therapeutic techniques where the bacteria that are normally susceptible to a treatment become resistant after surviving the outcome of the treatment. In both cases of acquired resistance, the bacteria can pass the genetic catalyst for resistance through horizontal gene transfer: conjugation, transduction, or transformation. This allows the resistance to spread across the same species of pathogen or even similar bacterial pathogens.
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 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.