If you have been reading about alpha-MSH analogue and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-03-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
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.
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 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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms differ |
| Molecular weight | Approximately 1024 g/mol | Calculated for the free base |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and polar solvents | Poorly soluble in non-polar solvents |
| Typical storage | -20 degrees Celsius, dry, protected from light | Refers to the solid form |
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.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
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.
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.
=== Emergency preparation === Guides for surviving emergency conditions in many parts of the world recommend maintaining a store of essential foods. A food storage calculator can help determine how much of these staple foods a person needs to store to sustain life for one full year. In addition to storing basic food items, many people choose to supplement their food storage with frozen or preserved garden-grown fruits and vegetables, as well as freeze-dried or canned produce. An unvarying diet of staple foods prepared in the same manner can cause appetite exhaustion, leading to less caloric intake. Another benefit of having a basic supply of food stored in the home is the potential for cost savings. Costs of dry bulk foods (before preparation) are often considerably less than convenience and fresh foods purchased at local markets or supermarkets. There is a significant market in convenience foods for campers, such as dehydrated food products.
==== Colleges and universities ==== Due to low standards and requirements in high school, many Americans are entering institutions of higher learning, including elite schools, with deficient reading comprehension skills and are unable and unwilling to complete long reading assignments. In addition, about a quarter of American university students failed to graduate within six years in the late 2010s and those who did faced diminishing wage premiums. As Generation Z enters high school and preparing for college, a primary concern is paying for a higher education without acquiring debt. As of 2019, the total college debt has exceeded $1.5 trillion, and two out of three college graduates are saddled with debt. In response to these challenges, many schools have diversified their sources of revenue in order to offer their students greater tuition discounts. Students also report interest in Reserve Officers' Training Corps (ROTC) programs as a means of covering college costs. Indeed, college subsidies are one of the most attractive things about signing up for military service. Another enticement is signing bonuses, whose amounts vary according to specialty. Domestic undergraduate enrollment since the early 2010s. Due to population aging, the number of college-aged people in the United States will fall after 2025, making it easier for people born in the late 2000s and after to get admitted.
=== Structure === There are three important structures in hydrocodone: the amine group, which binds to the tertiary nitrogen binding site in the central nervous system's opioid receptor, the hydroxy group that binds to the anionic binding site, and the phenyl group which binds to the phenolic binding site. This triggers a G protein activation and subsequent release of dopamine.
The units and notation above are used when dealing with the physics of mass spectrometry; however, the m/z notation is used for the independent variable in a mass spectrum. This notation eases data interpretation since it is numerically more related to the dalton. For example, if an ion carries one charge the m/z is numerically equivalent to the molecular or atomic mass of the ion in daltons (Da), where the numerical value of m/Q is abstruse. The m refers to the molecular or atomic mass number (number of nucleons) and z to the charge number of the ion; however, the quantity of m/z is dimensionless by definition. An ion with a mass of 100 Da (daltons) (m = 100) carrying two charges (z = 2) will be observed at m/z 50. However, the empirical observation m/z 50 is one equation with two unknowns and could have arisen from other ions, such as an ion of mass 50 Da carrying one charge. Thus, the m/z of an ion alone neither infers mass nor the number of charges. Additional information, such as the mass spacing between mass isotopomers or the relationship between multiple charge states, is required to assign the charge state and infer the mass of the ion from the m/z. This additional information is often but not always available. Thus, the m/z is primarily used to report an empirical observation in mass spectrometry. This observation may be used in conjunction with other lines of evidence to subsequently infer the physical attributes of the ion, such as mass and charge. On rare occasions, the thomson has been used as a unit of the x-axis of a mass spectrum.
Sources: en.wikipedia.org
Bacalhau – the Portuguese word for cod and, in a culinary context, dried and salted cod. Bacalhau dishes are common in Portugal, Brazil and Galicia, in the northwest of Spain, and to a lesser extent in former Portuguese colonies like Angola, Macau, and Goa. Balyk – salted and dried soft parts of fish, usually coming from large valuable species: acipenseridae (e.g., sturgeon) or salmonidae (salmon). Bokkoms – whole, salted and dried mullet (more specifically the Southern mullet, Liza richardsonii, a type of fish commonly known in the Western Cape of South Africa as "harders"), and is a well-known delicacy from the West Coast region of South Africa. Boknafisk – a variant of stockfish and is unsalted fish partially dried by sun and wind on drying flakes ('hjell') or on a wall. Boknafisk is mostly associated with North Norway, but it is eaten along the entire Norwegian coast down to Bergen. Budu – a sauce traditionally made by mixing anchovy and salt in the range of ratio of 2:1 to 6:1 and then fermenting for 140 to 200 days.
=== Electrical and electronics industry === Corona discharge on electrical apparatus can be detected by its ultraviolet emissions. Corona causes degradation of electrical insulation and emission of ozone and nitrogen oxide. EPROMs (Erasable Programmable Read-Only Memory) are erased by exposure to UV radiation. These modules have a transparent (quartz) window on the top of the chip that allows the UV radiation in.
== Etymology == The term "oxytocin" derives from the Greek ὀξυτόκιον (oxytokion), based on ὀξύς (oxús), meaning "sharp" or "swift", and τόκος (tókos), meaning "childbirth". The adjective form is "oxytocic", which refers to medicines that stimulate uterine contractions, to speed up the process of childbirth. Colloquially, it has been referred to as the "cuddle hormone," "hug hormone," or "love hormone" because of extensive evidence of its involvement in mating and social behavior. It is involved in mating behavior in animals as low as C. elegans.
== External links == "Melanocortin Receptors: MC4". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2016-03-03. Retrieved 2008-12-05. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
Secondary immunodeficiencies, also known as acquired immunodeficiencies, can result from various immunosuppressive agents, for example, malnutrition, aging, particular medications (e.g., chemotherapy, disease-modifying antirheumatic drugs, immunosuppressive drugs after organ transplants, glucocorticoids) and environmental toxins like mercury and other heavy metals, pesticides and petrochemicals like styrene, dichlorobenzene, xylene, and ethylphenol. For medications, the term immunosuppression generally refers to both beneficial and potential adverse effects of decreasing the immune system's functions. The term immunodeficiency generally refers solely to the adverse effect of increased risk of infection. Many specific diseases directly or indirectly cause immunosuppression. This includes many types of cancer, particularly those of the bone marrow and blood cells (leukemia, lymphoma, multiple myeloma), and certain chronic infections. Immunodeficiency is also the hallmark of acquired immunodeficiency syndrome (AIDS), caused by the human immunodeficiency virus (HIV). HIV directly infects a small number of T helper cells, and also impairs other immune system responses indirectly. Various hormonal and metabolic disorders can also result in immune deficiency, including anemia, hypothyroidism, and hyperglycemia. Smoking tobacco, heavy alcohol use, and substance use also depress the immune response. Heavy schedules of training and competition in athletes increases their risk of immune deficiencies.
Sources: en.wikipedia.org
EGTA (ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid), also known as egtazic acid (INN, USAN), is an aminopolycarboxylic acid, a chelating agent. It is a white solid that is related to the better known EDTA. Compared to EDTA, it has a lower affinity for magnesium, making it more selective for calcium ions. It is useful in buffer solutions that resemble the environment in living cells where calcium ions are usually at least a thousandfold less concentrated than magnesium. The pKa for binding of calcium ions by tetrabasic EGTA is 11.00, but the protonated forms do not significantly contribute to binding, so at pH 7, the apparent pKa becomes 6.91. See Qin et al. for an example of a pKa calculation. EGTA has also been used experimentally for the treatment of animals with cerium poisoning and for the separation of thorium from the mineral monazite. EGTA is used as a compound in elution buffer in the protein purification technique known as tandem affinity purification, in which recombinant fusion proteins are bound to calmodulin beads and eluted out by adding EGTA. EGTA is often employed in dentistry and endodontics for the removal of the smear layer.
== Overdose == Psilocybin has low toxicity, meaning that it has a low risk of inducing life-threatening events like breathing or heart problems. Research shows that health risks may develop with use of psilocybin. Nonetheless, hospitalizations from it are rare, and overdoses are generally mild and self-limiting. The lethal dose of psilocybin in humans is unknown, but has been estimated to be approximately 200 times a typical recreational dose. A review of the management of psychedelic overdoses suggested that psilocybin-related overdose management should prioritize managing the immediate adverse effects, such as anxiety and paranoia, rather than specific pharmacological interventions, as psilocybin's physiological toxicity tends to be rather limited. One analysis of people hospitalized for psilocybin poisoning found high urine concentrations of phenethylamine (PEA), suggesting that PEA might contribute to the effects of psilocybin poisoning. Despite acting as non-selective serotonin receptor agonists, psilocybin and other major serotonergic psychedelics like lysergic acid diethylamide (LSD) do not cause serotonin syndrome even in the context of extreme overdose. This is thought to be because they act as partial agonists of serotonin receptors like the serotonin 5-HT2A receptor, in contrast to serotonin itself, which is a full agonist. In rats, the median lethal dose (LD50) of psilocybin when administered orally is 280 mg/kg, approximately 1.5 times that of caffeine.
=== tRNA === Ψ is ubiquitous in this class of RNAs and facilitates common tRNA structural motifs. One such structural motif is the TΨC stem loop which incorporates Ψ55. Ψ is commonly found in the D stem and anticodon stem and loop of tRNAs from each domain. In each structural motif, the unique physicochemical properties of Ψ stabilize structures that would not be possible with the standard U. During translation, Ψ modulates interactions of tRNA molecules with rRNAs and mRNAs. Ψ and other modified nucleotides affect the local structure of the tRNA domains they are found in, without impacting the overall fold of the RNA. In the anticodon stem-loop (ASL), Ψ seems critical for proper binding of tRNAs to the ribosome. Ψ stabilizes the dynamic structure of the ASL and promotes stronger binding to the 30S ribosome. The stabilized conformation of the ASL helps maintain correct anticodon-codon pairings during translation. This stability may increase translational accuracy by decreasing the rate of peptide bond formation and allowing for more time for incorrect codon-anticodon pairs to be rejected. Despite Ψ's role in local structure stabilization, pseudouridylation of tRNA is not essential for cell viability and is not usually required for aminoacylation.
==== 2005 Tbilisi grenade attack ==== On May 10, 2005, while President Bush was giving a speech in Freedom Square, Vladimir Arutyunian, a native Georgian who was born to a family of ethnic Armenians, threw a live Soviet-made RGD-5 hand grenade toward the podium. It landed in the crowd about 61 feet (19 m) from the podium after hitting a girl, but it did not detonate because a red tartan handkerchief was wrapped tightly around it, preventing the safety lever from detaching. Georgian president Mikheil Saakashvili was seated nearby. After escaping that day, Arutyunian was arrested in July 2005. During his arrest, he killed an Interior Ministry agent. He was convicted in January 2006 and given a life sentence.
Sources: en.wikipedia.org
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.
Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.
Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.
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.