This is a working overview of melanocortin receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-09 and is reviewed periodically as new material appears.
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.
The peer-reviewed record is dominated by small early-phase studies, case reports and pharmacovigilance summaries rather than large randomised trials. Papers typically examine tanning response, receptor selectivity or patterns of reported adverse events. Many note that participants obtained the peptide outside a clinical setting, which limits verification of composition and administered amount. Reported events vary widely, and causality is frequently unclear because the identity and purity of self-sourced material are unknown. Open questions include whether repeated melanocortin receptor stimulation produces cumulative effects, and how often label claims match actual content.
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
Melanotan II holds no marketing authorisation from the Food and Drug Administration, the European Medicines Agency, the UK Medicines and Healthcare products Regulatory Agency or Australia's Therapeutic Goods Administration. Products sold under that name are treated as unapproved new drugs, and their sale or import is prohibited in several jurisdictions. Other countries classify the peptide as a prescription-only medicine or place it among controlled substances, so the legal position changes with the destination market. No pharmacopoeial monograph supplies an official specification, because the material is not a licensed pharmaceutical. Consequently, products offered online are not manufactured to a shared public standard.
| 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 |
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
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.
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.
In an exothermic reaction, the temperature in the sample cell increases upon addition of ligand. This causes the feedback power to the sample cell to be decreased (remember: a reference power is applied to the reference cell) in order to maintain an equal temperature between the two cells. In an endothermic reaction, the opposite occurs; the feedback circuit increases the power in order to maintain a constant temperature (isothermal operation). Observations are plotted as the power needed to maintain the reference and the sample cell at an identical temperature against time. As a result, the experimental raw data consists of a series of spikes of heat flow (power), with every spike corresponding to one ligand injection. These heat flow spikes/pulses are integrated with respect to time, giving the total heat exchanged per injection. By integrating each peak from the baseline, the total heat associated with each injection is obtained, including both reaction-specific and non-reaction-related contributions. The pattern of these heat effects as a function of the molar ratio [ligand]/[macromolecule] can then be analyzed to give the thermodynamic parameters of the interaction under study.
Bacterial infections such as mycoplasma, Legionnaires' disease, syphilis, listeriosis, or E. coli. Viral infections such Epstein-Barr virus, cytomegalovirus, mumps, varicella, rubella, adenovirus, HIV, influenza, or hepatitis C. Parasitic infections such as malaria or trypanosomiasis. Other autoimmune diseases such as systemic lupus erythematosus. Certain types of cancers such as lymphoma, chronic lymphocytic leukemia, Waldenström macroglobulinemia, multiple myeloma, and Kaposi sarcoma. In children, cold agglutinin disease is often secondary to an infection, such as Mycoplasma pneumonia, mononucleosis, and HIV.
== Structure == AMH is a dimeric glycoprotein with a molar mass of 140 kDa. The molecule consists of two identical subunits linked by sulfide bridges, and characterized by the N-terminal dimer (pro-region) and C-terminal dimer. AMH binds to its Type 2 receptor AMHR2, which phosphorylates a type I receptor under the TGF beta signaling pathway.
In addition, one case of mildly elevated liver enzymes (1 of 14; 7%), possibly related to bicalutamide, was observed but resolved spontaneously without discontinuation of therapy. Additional research is necessary to more clearly determine the true effectiveness and safety of bicalutamide and anastrozole in the treatment of FMPP. No long-term results for the BATT study have been published as of yet, but a 5-year follow-up of two of the boys in the study was published and reported continued effectiveness. It is intended that the study will continue until all of the boys reach adult final height, with an additional publication planned in the future. In addition to the BATT study, a variety of case reports and series of bicalutamide in combination with an aromatase inhibitor in male peripheral precocious puberty have been published. These case reports have described similar results as those of the BATT study. Alternatives to bicalutamide in the treatment of male peripheral precocious puberty include spironolactone, cyproterone acetate, and ketoconazole. Bicalutamide with anastrozole is considered to be superior to the combination of spironolactone and testolactone in peripheral precocious puberty, with greater efficacy and fewer side effects. This corresponds to the fact that bicalutamide is a much more potent and selective antiandrogen than spironolactone. Additionally, dosing is easier with bicalutamide, as it requires administration only once daily as opposed to twice daily at 12-hour intervals with spironolactone.
Sources: en.wikipedia.org
Some Māori tribes from New Zealand would keep mummified heads as trophies from tribal warfare. They are also known as Mokomokai. In the 19th century, many of the trophies were acquired by Europeans who found the tattooed skin to be a phenomenal curiosity. Westerners began to offer valuable commodities in exchange for the uniquely tattooed mummified heads. The heads were later put on display in museums, 16 of them in France alone. In 2010, at a ceremony in the Hôtel de Ville in Rouen, Rouen City Council returned one of the heads to New Zealand, despite earlier protests by the Culture Ministry of France. There is also evidence that some Māori tribes may have practiced full-body mummification, though the practice is not thought to have been widespread. The discussion of Māori mummification has been historically controversial, with some experts in past decades claiming that such mummies have never existed. The historical significance of full-body mummification within Māori culture is acknowledged by science, although there is still debate as to the nature of their exact mummification processes. Some mummies appear to have been spontaneously created by the natural environment, while others exhibit signs of direct human involvement. Generally, modern consensus tends to agree that there could have been a mixture of both types of mummification, similar to that of the Ancient Egyptian culture.
=== Scalp hair loss and excessive hair growth === Dutasteride is approved for the treatment of male androgenetic alopecia in South Korea, Japan, and Taiwan at a dosage of 0.5 mg per day. Several studies have found it to induce hair regrowth in men more rapidly and to a greater extent than even the highest approved dosage of finasteride. The superior effectiveness of dutasteride relative to finasteride for this indication is because the inhibition of 5α-reductase and consequent reduction of dihydrotestosterone (DHT) production within the hair follicles is more complete with dutasteride. Dutasteride is also used off-label in the treatment of female pattern hair loss. Other 5α-reductase inhibitors such as finasteride (a type 2 inhibitor) have been used off-label to treat excessive hair growth in women with hirsutism. Since dutasteride is an inhibitor of both type 1 and 2 5α-reductases, it could theoretically be a more effective therapy for hirsutism. However, dutasteride is not recommended for this indication due to a lack of supportive clinical evidence and a substantial risk of birth defects in female patients who inadvertently become pregnant.
The Washington Post also followed up with a correction of errors in its earlier report on the Smithsonian acquisition, stating that it incorrectly referred to Ayyadurai as the inventor of electronic messaging; the 'bcc', 'cc', 'to' and 'from' fields existed previously; Ayyadurai had not been honored as the "inventor of email". Writing for Gizmodo, Sam Biddle argued that email was developed a decade before EMAIL, beginning with Ray Tomlinson's sending the first text letter between two ARPANET-connected computers in 1971. Biddle quoted Tomlinson: "[We] had most of the headers needed to deliver the message (to:, cc:, etc.) as well as identifying the sender (from:) and when the message was sent (date:) and what the message was about." Biddle allowed for the possibility that Ayyadurai may have coined the term "EMAIL" and used the header terms without being aware of earlier work, but maintained that the historical record isn't definitive on either point. Biddle wrote that "laying claim to the name of a product that's the generic term for a universal technology gives you acres of weasel room.
A 2016 WHO report found that formaldehyde from second-hand vapor was around 20% greater compared to background air levels. Normal usage of e-cigarettes generates very low levels of formaldehyde. Different power settings reached significant differences in the amount of formaldehyde in the e-cigarette vapor across different devices. Later-generation e-cigarette devices can create greater amounts of carcinogens. Some later-generation e-cigarettes let users increase the volume of vapor by adjusting the battery output voltage. Depending on the heating temperature, the carcinogens in the e-cigarette vapor may surpass the levels of cigarette smoke. E-cigarettes devices using higher voltage batteries can produce carcinogens including formaldehyde at levels comparable to cigarette smoke. The later-generation and "tank-style" devices with higher voltages (5.0 V) could produce formaldehyde at comparable or greater levels than in cigarette smoke. A 2015 study hypothesized from the data that at high voltage (5.0 V), a user, "vaping at a rate of 3 mL/day, would inhale 14.4 ± 3.3 mg of formaldehyde per day in formaldehyde-releasing agents." The 2015 study used a puffing machine showed that a third-generation e-cigarette turned on to the maximum setting would create levels of formaldehyde between five and 15 times greater than with cigarette smoke.
electroporation Also electropermeabilization. A molecular biology technique in which a strong electric field is applied to living cells in order to temporarily increase the permeability of their cell membranes, allowing exogenous nucleic acids, proteins, or chemical compounds to easily pass through the membrane and thereby enter the cells. It is a common method of achieving transformation and transfection.
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.
Regulatory treatment varies by country. In the United States, the European Union and Australia it is an unapproved drug and its sale is restricted, while some other jurisdictions list it as prescription-only or controlled. The applicable rules depend on the country of import.