Everything below concerns Alpha-MSH. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
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.
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 absolute speed record for wind at Le Havre – Cap de la Heve was recorded on 16 October 1987 at 180 kilometres per hour (112 miles per hour). The main natural hazards are floods, storms, and storm surges. The lower town is subject to a rising water table. The lack of watercourses within the commune prevents flooding from overflows. Le Havre's beach may rarely experience flooding known as "flooding from storms". These are caused by the combination of strong winds, high waves, and a large tidal range.
Reith revealed in a 2009 letter to the Journal of the Royal College of Physicians of Edinburgh that she and her colleagues made no money from the invention, with the then Greater Glasgow Health Board holding the patent on their behalf and receiving income until it sold the rights to pharmaceutical company Novo.
However the quality and yield of these varieties are poor as compared to non-resistant strains and only Consort is reliably self-fertile. Back-crossing these varieties to a parent have produced new strains such as 'Titania' that have a higher yield, better disease resistance, are more tolerant of adverse weather conditions and are suitable for machine harvesting. Two new releases from a black currant breeding program in British Columbia, Canada, 'Blackcomb' and 'Tahsis', were selected for their immunity to white pine blister rust and their frost tolerance.
Sources: en.wikipedia.org
=== Acidity === Thiols are easily deprotonated. Relative to the alcohols, thiols are more acidic. The conjugate base of a thiol is called a thiolate. Butanethiol has a pKa of 10.5 vs 15 for butanol. Thiophenol has a pKa of 6, versus 10 for phenol. A highly acidic thiol is pentafluorothiophenol (C6F5SH) with a pKa of 2.68. Thus, thiolates can be obtained from thiols by treatment with alkali metal hydroxides.
Recreational users sometimes open dexedrine capsules and crush the contents in order to insufflate (snort) it or subsequently dissolve it in water and inject it. Immediate-release formulations have higher potential for abuse via insufflation (snorting) or intravenous injection due to a more favorable pharmacokinetic profile and easy crushability (especially tablets). Injection into the bloodstream can be dangerous because insoluble fillers within the tablets can block small blood vessels. Chronic overuse of dextroamphetamine can lead to severe drug dependence, resulting in withdrawal symptoms when drug use stops.
An isotope (nuclide) is specified by the name of the element (which implies the atomic number) followed by a hyphen and the mass number (e.g. helium-3, helium-4, carbon-12, carbon-14, uranium-235 and uranium-239). When a element symbol is used, e.g. "C" for carbon, it is standard to use "AZE notation" which has the form AZE, where A is the mass number written as a superscript, Z is the atomic number written as a subscript, and E is the element symbol (e.g. 32He, 42He, 126C, 146C, 23592U, and 23992U). Because the atomic number is already fixed by the element symbol, it is common to state only the mass number in the superscript and leave out the atomic number subscript (e.g. 3He, 4He, 12C, 14C, 235U, and 239U). The letter m (for metastable) is appended after the mass number to indicate a nuclear isomer, a metastable or energetically excited nuclear state (as opposed to the lowest-energy ground state), for example 180m73Ta (tantalum-180m); a number can be appended to it to distinguish different metastable states, though this is rare in practice. The common pronunciation of the AZE notation is different from how it is written: 42He is commonly pronounced helium-four instead of four-two-helium, and 23592U uranium two-thirty-five (American English) or uranium-two-three-five (British) instead of 235-92-uranium or 235-uranium. This is not an error but the original spoken usage for isotope names, originating before AZE notation became established.
Sources: en.wikipedia.org
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.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.