The short version of alpha-MSH analogue fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-21. Anything still debated is marked as such rather than presented as settled.
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.
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 |
|---|---|---|
| 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 |
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
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.
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 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.
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.
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.
=== Metals === Pure alkali metals are dangerously reactive with air and water and must be kept away from heat, fire, oxidising agents, acids, most organic compounds, halocarbons, plastics, and moisture. They also react with carbon dioxide and carbon tetrachloride, so that normal fire extinguishers are counterproductive when used on alkali metal fires. Some Class D dry powder extinguishers designed for metal fires are effective, depriving the fire of oxygen and cooling the alkali metal. Experiments are usually conducted using only small quantities of a few grams in a fume hood. Small quantities of lithium may be disposed of by reaction with cool water, but the heavier alkali metals should be dissolved in the less reactive isopropanol. The alkali metals must be stored under mineral oil or an inert atmosphere. The inert atmosphere used may be argon or nitrogen gas, except for lithium, which reacts with nitrogen. Rubidium and caesium must be kept away from air, even under oil, because even a small amount of air diffused into the oil may trigger formation of the dangerously explosive peroxide; for the same reason, potassium should not be stored under oil in an oxygen-containing atmosphere for longer than 6 months.
== Pathophysiology == GOSR2 is a protein that is classified as a t-SNARE and includes SNARE domain which is important for vesicle fusion; in EPM6, GOSR2 function is compromised. In Drosophila model, GOSR2 mutation might cause deficiency in dendritic growth and disrupts evoked and spontaneous release of neurotransmitter.
== Outlook == The long-term course of MCTD may vary. Long-term follow-up studies have shown that MCTD can progress to a moderate disease with a favorable prognosis, or patients can acquire a significant condition with vascular alterations driven by pulmonary hypertension and increased mortality. Approximately one-third of people with MCTD have a benign course and go into remission, while the other one-third have a more aggressive course with a poor response to treatment. Approximately one-third of MCTD patients improved with immunosuppressive medication but continued to require immunosuppressive therapy after several years. The prevalence of pulmonary hypertension was related to the worst prognosis and a high mortality rate, making it the most significant complication in MCTD.
Gun rights organizations pledged to challenge the law in court, saying, "Almost the entire bill is a constitutional issue", according to the Illinois State Rifle Association. An Effingham County judge issued a temporary injunction preventing implementation of the law on January 20, 2023. The Illinois Supreme Court ruled the law constitutional and allowed it to take effect. Lawsuits are also pending in federal court and in Crawford County.
Sources: en.wikipedia.org
The initial effects of exposure were coughing, severe eye irritation, a feeling of suffocation, burning in the respiratory tract, blepharospasm, breathlessness, stomach pains, and vomiting. People alerted by these symptoms fled from the plant. Those who ran inhaled more than those in vehicles. Owing to their height, children and other residents of shorter stature inhaled higher concentrations, as methyl isocyanate gas is approximately twice as dense as air and in an open environment has a tendency to fall toward the ground. Thousands of people had died by the following morning. Primary causes of deaths were choking, reflexogenic circulatory collapse, and pulmonary oedema. Findings during autopsies revealed changes not only in the lungs but also cerebral oedema, tubular necrosis of the kidneys, fatty degeneration of the liver, and necrotising enteritis. The individuals who did not die suffered from cancer, blindness, loss of livelihood, and financial strain.
The large range and marked variability between individuals is due to variation in factors including product matrix, ignition temperature, and inhalational dynamics (e.g., number, duration, and intervals of inhalations, breath hold time, depth and volume of inhalations, size of inhaled particles, deposition site in the lungs). THC is detectable within seconds with inhalation and peak levels of THC occur after 3 to 10 minutes. Smoking or inhaling THC results in greater blood levels of THC and its metabolites and a much faster onset of action than oral administration of THC. Inhalation of THC bypasses the first-pass metabolism that occurs with oral administration. The bioavailability of THC with inhalation is increased in heavy users. Transdermal administration of THC is limited by its extreme water insolubility. Efficient skin transport can only be obtained with permeation enhancement. Transdermal administration of THC, as with inhalation, avoids the first-pass metabolism that occurs with oral administration.
With the exception of biopharmaceuticals, which are manufactured by only a few selected fine chemical companies, the technology toolboxes of all these companies are similar. This means that they can carry out practically all types of chemical reactions. They differentiate on the basis of the breadth and quality of the service offering.
== Diagnosis == The diagnosis of Fuchs dystrophy is often made with slit lamp biomicroscopy. With direct illumination, the clinician can visualize guttae, the characteristic pathological changes in disease. Scheimpflug imaging, anterior segment optical coherence tomography, confocal microscopy, and specular microscopy are additional imaging techniques that can identify the presence of guttae and quantify the thickness of the cornea. While corneal thickness can be a valuable indicator of how the cornea is changing over time, it is affected by multiple factors and is not adequate itself as a screening tool to diagnose Fuchs dystrophy.
== History == Buspirone was first synthesized by a team at Mead Johnson in 1968 but was not patented until 1980. It was initially developed as an antipsychotic acting on the D2 receptor but was found to be ineffective in the treatment of psychosis; it was then used as an anxiolytic. In 1986, Bristol-Myers Squibb gained FDA approval for buspirone in the treatment of GAD. The patent expired in 2001, and buspirone is available as a generic drug.
Sources: en.wikipedia.org
== Adverse effects == The US Food and Drug Administration prescribing information contains a boxed warning for embryo-fetal toxicity. The most common adverse reactions include diarrhea, infusion-related reactions, abdominal pain, and fatigue.
Later, the Portales doctrine would be applied when Chile intervened in the War of the Confederation on the side of the United Restoration Army. However, from the beginning the Chilean press clarified that the war was against Andres de Santa Cruz and not against Peru, therefore, this anti-Peruvianism is particularly associated with the War of the Pacific, a war between Chile and the Peruvian-Bolivian alliance, which began in 1879 and culminated in the loss of Bolivia's access to the sea and the Peruvian territories of the province of Arica and the department of Tarapacá in favor of Chile. In addition, during the Occupation of Lima, there were plans to disappear Peru as a state, under the formula of Annexation or anarchy, which tried to base itself on anti-Peruvian brains, accusing Peru of being a country populated by an inferior race of "rebels by profession.", being an idle, effeminate, cowardly and anarchic people, which is therefore incapable of governing itself; while the solution to Peruvian instability was to annex the Chilean nation, made up of a privileged, progressive and civilizing race, of European extraction. Having consequently an extremely anti-Peruvian policy during the occupation of Tacna, where there were several aggressive altercations with the native population in the Chileanization of Tacna, Arica and Tarapacá. At that time, the Ministry of Foreign Affairs of Chile was assumed by Mr.
=== Undigested food remnants === Sometimes undigested food may make an appearance in feces. Common undigested foods found in human feces are seeds, nuts, and corn, mainly because of their high fiber content. Beets may turn feces different hues of red. Artificial food coloring in some processed foods, such as highly colorful packaged breakfast cereals, can cause an unusual coloring of feces if eaten in sufficient quantities. Undigested objects such as seeds can pass through the human digestive system, and later germinate. One result of this is tomato plants growing where treated sewage sludge has been used as fertilizer.
== Contraindications == Contraindications of tiagabine include hypersensitivity (drug allergy) to tiagabine or its ingredients and severe hepatic impairment. The drug should be avoided in pregnant and nursing women.
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 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.