alpha-MSH analogue raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-24. Anything still debated is marked as such rather than presented as settled.
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.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
| 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 |
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
=== Strength === Strong salts or strong electrolyte salts are chemical salts composed of strong electrolytes. These salts dissociate completely or almost completely in water. They are generally odorless and nonvolatile. Most group 1 and 2 metals form strong salts. Strong salts are especially useful when creating conductive compounds as their constituent ions allow for greater conductivity. Weak salts or weak electrolyte salts are composed of weak electrolytes. These salts do not dissociate well in water. They are generally more volatile than strong salts. They may be similar in odor to the acid or base they are derived from. For example, sodium acetate, CH3COONa, smells similar to acetic acid CH3COOH.
=== Transportation === Rhodesia had its own road and rail network along with an airline, Air Rhodesia. The road network largely was found in white areas and there were by 1975 "about" 45,000 miles (72,000 km) of paved roads. The railroad network was 1,568 miles (2,523 km) long and matched the South African railroad gauge. Rhodesia also had connections via road and rail to neighboring countries.
Histiocytoma is a common, benign, cutaneous neoplasm in dogs. Histiocytomas usually occur as solitary lesions, which spontaneously regress, and seldom recur. They can occur in dogs of all ages, but are more likely in dogs under three years of age. Epidermal invasion by cells of histiocytoma frequently occurs and intra-epidermal nests of histiocytes resemble Pautrier's aggregates, characteristically found in epidermotropic lymphoma (Mycosis Fungoides or MF). Epidermal invasion in histiocytoma, or presence of simultaneous multiple histiocytomas, especially in aged dogs, can appear similar to MF or non-epidermotropic cutaneous lymphoma (NECL). Multiple histiocytomas may look like cutaneous histiocytosis, although morphologically histiocytomas are consistently epidermotropic and commonly epidermally invasive, these are not features of cutaneous histiocytosis. Delayed regression of multiple histiocytomas can occur and lesions can persist for up to 10 months.
LSD was initially explored for psychiatric use due to its structural similarity to the neurotransmitter serotonin and its safety profile. In the 1950s and 1960s, it was used in psychiatry to enhance psychotherapy, known as psychedelic therapy. In the United States, the earliest research began in the 1950s. Albert Kurland and his colleagues published research on LSD's therapeutic potential to treat schizophrenia. In Canada, Humphry Osmond and Abram Hoffer completed LSD studies as early as 1952. Some psychiatrists, such as Ronald A. Sandison, who pioneered its use at Powick Hospital in England, believed that LSD was especially useful at helping patients to "unblock" repressed subconscious material through other psychotherapeutic methods, and also for treating alcoholism. One study concluded, "The root of the therapeutic value of the LSD experience is its potential for producing self-acceptance and self-surrender," presumably by forcing the user to face issues and problems in that individual's psyche. By the 1960s, however, controversies surrounding "hippie" counterculture began to deplete institutional support for continued study. In 2001, the United States Drug Enforcement Administration (DEA) stated that LSD "produces no aphrodisiac effects, does not increase creativity, has no lasting positive effect in treating alcoholics or criminals, does not produce a "model psychosis", and does not generate immediate personality change." In more recent years, there has been renewed clinical research on and interest in LSD for potential therapeutic uses.
Sources: en.wikipedia.org
As in all other tetrapods, mammals have a larynx that can quickly open and close to produce sounds, and a supralaryngeal vocal tract which filters this sound. The lungs and surrounding musculature provide the air stream and pressure required to phonate. The larynx controls the pitch and volume of sound, but the strength the lungs exert to exhale also contributes to volume. More primitive mammals, such as the echidna, can only hiss, as sound is achieved solely through exhaling through a partially closed larynx. Other mammals phonate using vocal folds. The movement or tenseness of the vocal folds can result in many sounds such as purring and screaming. Mammals can change the position of the larynx, allowing them to breathe through the nose while swallowing through the mouth, and to form both oral and nasal sounds; nasal sounds, such as a dog whine, are generally soft sounds, and oral sounds, such as a dog bark, are generally loud.
=== Synthesis === For the synthesis of alprazolam the same method can be used as for triazolam, except that it starts from 2-amino-5-chlorobenzophenone. However, an alternative easier synthesis starting with 2,6-dichloro-4-phenylquinoline has been suggested, in which it reacts with hydrazine giving 6-chloro-2-hydrazino-4-phenylquinoline. Boiling the mixture with triethyl orthoacetate results in cyclization with the formation of the triazole ring. The product undergoes oxidative degradation in the presence of periodate and ruthenium dioxide in acetone solution, giving 2-[4-(3'-methyl-1,2,4-triazolo)]-5-chlorobenzophenone. Oxy-methylation with formaldehyde results in a product that is treated with phosphorus tribromide when 2-[4-(3'-methyl-5'-bromomethyl-1,2,4-triazolo)]-5-chlorobenzophenone is obtained. By substituting the bromine atom with an amino group conferred by ammonia, it forms alprazolam triazolobenzophenone, following which an intramolecular heterocyclization takes place to obtain alprazolam.
Merck & Co. adapted the 1936 laboratory-scale synthesis, allowing them to manufacture thiamine in Rahway in 1937. However, an alternative route using the intermediate Grewe diamine (5-(aminomethyl)-2-methyl-4-pyrimidinamine), first published in 1937, was investigated by Hoffman La Roche and competitive manufacturing processes followed. Efficient routes to the diamine have continued to be of interest. In the European Economic Area, thiamine is registered under REACH regulation and between 100 and 1,000 tonnes per annum are manufactured or imported there.
Computational techniques are used to analyse high-throughput, low-measurement single cell data, such as that obtained from flow cytometry. These methods typically involve finding populations of cells that are relevant to a particular disease state or experimental condition.
which means that the divergence of the velocity field is zero everywhere. Physically, this is equivalent to saying that the local volume dilation rate is zero, hence a flow of water through a converging pipe will adjust solely by increasing its velocity as water is largely incompressible.
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.
The dry powder is more stable during transport and storage than a solution. It also allows a known amount of material to be reconstituted at a chosen concentration.