The short version of melanocortin fits in a sentence. The long version — which is the one that helps — is below.
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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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
| 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 |
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.
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.
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.
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.
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-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.
Since entering the market around 2003, e-cigarette use has risen rapidly. In 2011 there were about 7 million adult e-cigarette users globally, increasing to 68 million in 2020 compared with 1.1 billion cigarette smokers. There was a further rise to 82 million e-cigarette users in 2021. This increase has been attributed to targeted marketing, and ecigs being cheaper and safer than combustible cigarettes. E-cigarette use is highest in China, the US, and Europe, with China having the most users.
== Causes == DEB is caused by genetic defects (or mutations) within the human COL7A1 gene encoding the protein type VII collagen (collagen VII). DEB-causing mutations can be either dominant or recessive. Most families with family members with this condition have distinct mutations. Collagen VII is a very large molecule (300 kDa) that dimerizes to form a semicircular looping structure: the anchoring fibril. Anchoring fibrils are thought to form a structural link between the epidermal basement membrane and the fibrillar collagens in the upper dermis.
=== Allies === Wolverine is primarily presented as part of the X-Men and has had extensive interactions with all of them and their associates. Nightcrawler is one of his closest friends and was one of the first X-Men to look past Logan's demeanor, which was initially quite abrasive. Wolverine has also teamed up with Gambit on missions separate from the rest of the X-Men. In particular, Wolverine has a complex and ambivalent relationship with Cyclops, with whom he was initially a rival for the affections of Jean Grey. Logan was one of the original member of Alpha Flight, although he left the group out of frustration with their role as Canadian government operatives. He has also been a member of the Avengers, X-Force, and at times has joined the Fantastic Four. Outside his team allegiances, he has frequently allied with Elektra, particularly during periods when it becomes necessary for him to regain control of his impulses.
In his book TiHKAL (Tryptamines I Have Known and Loved), Alexander Shulgin lists the same dose range of 10 to 20 mg orally and duration of 3 to 6 hours for psilocin, psilocybin, and 4-AcO-DMT. Another publication gave a 4-AcO-DMT dose range of 10 to 15 mg orally, with a typical dose of 12.5 mg orally, and a duration of about 5 to 8 hours. A further source gave a dose range for the drug of 5 to 30 mg orally, an onset of 15 to 40 minutes, and a duration of 4 to 7 hours. 4-AcO-DMT is a prodrug of psilocin similarly to psilocybin and its effects are reported to be similar or identical to those of psilocybin and psilocybin-containing mushrooms. However, it is said to produce less nausea and body load than psilocybin-containing mushrooms. The drug is also often described as having a faster onset and shorter duration than psilocybin. 4-AcO-DMT exposure results in modestly lower peripheral plasma concentrations of psilocin by weight than psilocybin in animals when they are given at equimolar doses. Specific effects of 4-AcO-DMT have been reported to include psychedelic visuals, closed-eye imagery, synesthesia, insights, disembodiment, euphoria, feelings of bliss and unity, oceanic boundlessness, ego dissolution, sedation, cognitive impairment, and spiritual experiences, among others. Adverse effects have been reported to include psychological side effects such as anxiety, paranoia, and low mood as well as gastrointestinal side effects such as nausea and vomiting.
== Family == Convulxin is part of the snake venom C-type lectin family, a group of hemorrhagic toxins that disrupt body homeostasis. The name describes their similarity in structure to C-type lectins from other animals, proteins that bind calcium to induce various signalling pathways. Proteins of about 130 amino acids in length, C-type lectins contain at least a carbohydrate recognition domain (CRD), which mediates sugar and calcium binding. They are involved in various biological activities, ranging from cell-cell adhesion, serum glycoprotein turnover, to immune responses and cell apoptosis.
Sources: en.wikipedia.org
== Side effects == The most common side effect of verapamil is constipation (7.3%). While the definite mechanism by which verapamil causes constipation has not been studied, studies have been conducted to rule out mechanisms of actions that might yield this adverse effect. A 1992 study found that verapamil causes a delay in colonic transit but does not affect upper gastrointestinal transit. Other side effects include dizziness (3.3%), nausea (2.7%), low blood pressure (2.5%), and headache 2.2%. Other side effects seen in less than 2% of the population include: edema, congestive heart failure, pulmonary edema, diarrhea, fatigue, elevated liver enzymes, shortness of breath, low heart rate, atrioventricular block, rash and flushing. Along with other calcium channel blockers, verapamil is known to induce gingival enlargement.
=== Other endurance sports === In triathlon, 2004 Hawaii Ironman winner Nina Kraft, was disqualified for a positive test to EPO. She remains the only Hawaii Ironman winner to be disqualified for doping offences. Sports lawyer Michelle Gallen has said that the pursuit of doping athletes has turned into a modern-day witch-hunt.
where j is the position of the amino acid in the four-residue window. If p(t) exceeds an arbitrary cutoff value (originally 7.5e–3), the mean of the p(j)'s exceeds 1, and p(t) exceeds the alpha helix and beta sheet probabilities for that window, then a turn is predicted. If the first two conditions are met but the probability of a beta sheet p(b) exceeds p(t), then a sheet is predicted instead.
=== Redox === Silver(I) salts are mild oxidants, as implicated by their role in silver-based photography and the staining of skin by silver metal upon contact with silver nitrate solutions. Characteristically, silver nitrate reacts with pieces of copper to form hairlike crystals of silver metal and a blue solution of copper nitrate:
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.
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.