Everything below concerns salt form. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-06. Numbers and descriptions here follow the published literature rather than marketing material.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
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.
| Property | Value | Notes |
|---|---|---|
| Lyophilised storage | −20 °C, dry, protected from light | Vials are sealed and allowed to reach room temperature before opening |
| Reconstituted storage | 2 to 8 °C, protected from light | Short-term holding; avoid repeated freeze-thaw cycles |
| Reconstitution solvent | Water for injection or bacteriostatic water | Added slowly along the vial wall to reduce foaming and shear |
| Purity measurement | RP-HPLC with area normalisation | Acetonitrile-water gradient monitored at roughly 214 nm |
| Identity confirmation | Electrospray ionisation mass spectrometry | Observed mass compared against the calculated peptide mass |
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Identity testing for a synthetic peptide relies on several complementary methods. Reversed-phase high-performance liquid chromatography separates the target from related impurities and reports purity as a percentage of total peak area. Mass spectrometry confirms molecular mass and can reveal deletions or truncations. Amino acid analysis and peptide mapping provide sequence-level confirmation, while counter-ion content and residual solvents are measured separately. A purity figure alone does not establish identity, so a complete dataset combines chromatographic and spectrometric evidence.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
In October 2025, Moore announced an agreement between the state and Constellation Energy that would allow the Conowingo Dam to continue operations for another 50 years, but required the company to spend $341 million on a series of renovations to support fish migration through the damn and limit pollution flowing through it to the lower Susquehanna River and the Chesapeake Bay.
In September 2017, Pinnacle Health, a seven-hospital system in South Central Pennsylvania, merged with UPMC and also with Hanover Hospital. Cole Memorial hospital partnered with UPMC Susquehanna and merged with the UPMC system in March 2018. Somerset Hospital, located in Somerset, Pennsylvania, merged with UPMC on February 1, 2019. On February 3, 2020, Western Maryland Health System became the first Maryland hospital to join the UPMC system. Washington Health System merged with UPMC in 2024, resulting in the operation of over 35 academic, community, and specialty hospitals in Pennsylvania, Maryland, and New York, as well as over 600 outpatient sites and doctors' offices, more than 50 facilities for physical, occupational, speech and specialty therapies, and 14 retirement and long-term care site, along with its international and for-profit ventures.
Orthogonal protection is a strategy allowing the specific deprotection of one protective group in a multiply-protected structure. For example, the amino acid tyrosine could be protected as a benzyl ester on the carboxyl group, a fluorenylmethylenoxy carbamate on the amine group, and a tert-butyl ether on the phenol group. The benzyl ester can be removed by hydrogenolysis, the fluorenylmethylenoxy group (Fmoc) by bases (such as piperidine), and the phenolic tert-butyl ether cleaved with acids (e.g. with trifluoroacetic acid). A common example for this application, the Fmoc peptide synthesis, in which peptides are grown in solution and on solid phase, is very important. The protecting groups in solid-phase synthesis regarding the reaction conditions such as reaction time, temperature and reagents can be standardized so that they are carried out by a machine, while yields of well over 99% can be achieved. Otherwise, the separation of the resulting mixture of reaction products is virtually impossible (see also § Industrial applications).
Diazepam is mainly used to treat anxiety, insomnia, panic attacks, and symptoms of acute alcohol withdrawal. It is also used as a premedication for inducing sedation, anxiolysis, or amnesia before certain medical procedures (e.g., endoscopy). In 2020, it was approved for use in the United States as a nasal spray to interrupt seizure activity in people with epilepsy. Diazepam is the most commonly used benzodiazepine for "tapering" benzodiazepine dependence due to diazepam's comparatively long half-life, allowing for more efficient dose reduction. Benzodiazepines have a relatively low toxicity in overdose. Diazepam has several uses, including:
Gemtuzumab ozogamicin, sold under the brand name Mylotarg, is an antibody-drug conjugate (a drug-linked monoclonal antibody) that is used to treat acute myeloid leukemia (AML). The most common side effects include infection, febrile neutropenia, decreased appetite, hyperglycemia, mucositis, hypoxia, hemorrhage, increased transaminase, diarrhea, nausea, and hypotension. However, the addition of gemtuzumab ozogamicin to standard chemotherapy regimens does not increase infection rates.
Sources: en.wikipedia.org
Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed. But he precedes that remark by, "Analogy would lead me one step further, namely, to the belief that all animals and plants have descended from some one prototype. But analogy may be a deceitful guide." And in the subsequent edition, he asserts rather, "We do not know all the possible transitional gradations between the simplest and the most perfect organs; it cannot be pretended that we know all the varied means of Distribution during the long lapse of years, or that we know how imperfect the Geological Record is. Grave as these several difficulties are, in my judgment they do not overthrow the theory of descent from a few created forms with subsequent modification". Common descent was widely accepted amongst the scientific community after Darwin's publication. In 1907, Vernon Kellogg commented that "practically no naturalists of position and recognized attainment doubt the theory of descent." In 2008, biologist T. Ryan Gregory noted that:
Many buildings in the city are classified as "historical monuments", but the 2000s marked the real recognition of Le Havre's architectural heritage. The city received the label "City of Art and History" in 2001, then in 2005 UNESCO inscribed the city of Le Havre as a World Heritage Site. The oldest building still standing in Le Havre is the Graville Abbey. The other medieval building in the city is the Chapel of Saint-Michel of Ingouville. Because of the bombing in 1944, heritage from the modern era is rare: Le Havre Cathedral, the Church of Saint Francis, the Museum of the Hotel Dubocage of Bleville, the House of the ship-owner and the old palace of justice (now the Natural History Museum) are concentrated in the Notre-Dame and Saint-François areas. The buildings of the 19th century testify to the maritime and military vocations of the city: the Hanging Gardens, the Fort of Tourneville, Vauban docks, and the Maritime Villa. The heritage of the 1950s and 1960s which were the work of the Auguste Perret workshop forms the most coherent architecture: the Church of Saint Francis and the Town Hall are the centrepieces. The all curved architecture of the "Volcano", designed by Oscar Niemeyer, contrasts with that of the rebuilt centre. Finally, the reconstruction of many districts is a showcase for the architecture of the 21st century. Among the achievements by renowned architects are the Chamber of Commerce and Industry (René and Phine Weeke Dottelond), Les Bains Des Docks (Jean Nouvel). °
== Sticky-end ligation == Restriction enzymes can generate a wide variety of ends in the DNA they digest, but in cloning experiments most commonly used restriction enzymes generate a 4-base single-stranded overhang called the sticky or cohesive end (exceptions include NdeI which generates a 2-base overhang, and those that generate blunt ends). These sticky ends can anneal to other compatible ends and become ligated in a sticky-end (or cohesive end) ligation. EcoRI for example generates an AATT end, and since A and T have lower melting temperature than C and G, its melting temperature Tm is low at around 6°C. For most restriction enzymes, the overhangs generated have a Tm that is around 15°C. For practical purposes, sticky end ligations are performed at 12-16°C, or at room temperature, or alternatively at 4°C for a longer period. For the insertion of a DNA fragment into a plasmid vector, it is preferable to use two different restriction enzymes to digest the DNA so that different ends are generated. The two different ends can prevent the religation of the vector without any insert, and it also allows the fragment to be inserted in a directional manner. When it is not possible to use two different sites, then the vector DNA may need to be dephosphorylated to avoid a high background of recircularized vector DNA with no insert. Without a phosphate group at the ends the vector cannot ligate to itself, but can be ligated to an insert with a phosphate group.
== Distribution and habitat == The death cap is native to Europe, where it is widespread. It is found from the southern coastal regions of Scandinavia in the north, to Ireland in the west, east to Poland and western Russia, and south throughout the Balkans, in Greece, Italy, Spain, and Portugal in the Mediterranean basin, and in Morocco and Algeria in north Africa. In west Asia, it has been reported from forests of northern Iran. There are records from further east in Asia but these have yet to be confirmed as A. phalloides. By the end of the 19th century, Charles Horton Peck had reported A. phalloides in North America. In 1918, samples from the eastern United States were identified as being a distinct though similar species, A. brunnescens, by George Francis Atkinson of Cornell University. By the 1970s, it had become clear that A. phalloides does occur in the United States, apparently having been introduced from Europe alongside chestnuts, with populations on the West and East Coasts. A 2006 historical review concluded the East Coast populations were inadvertently introduced, likely on the roots of other purposely imported plants such as chestnuts. The origins of the West Coast populations remained unclear, due to scant historical records, but a 2009 genetic study provided strong evidence for the introduced status of the fungus on the west coast of North America. Observations of various collections of A. phalloides, from conifers rather than native forests, have led to the hypothesis that the species was introduced to North America multiple times.
== Retirement == Meurgues retired to Saint-Germain-de-Modéon, continuing to write articles in specialist magazines, sharing her knowledge in museology and scriptwriting, as well as restoring the family farm and creating an animal rescue refuge. She donated her scientific library to the Muséum d'Autun and is preparing a book Inventions et bricolages de la nature. She published Du jardin de Buffon à l'Afghanistan: mémoires d'une naturaliste in 2019. Geneviève Meurgues died on 21 December 2021, in her 91st year. According to her last wishes, her cremation was private and her ashes will be spread in the "Les Grands Bouchons" wood, where her vocation as a naturalist was born.
Sources: en.wikipedia.org
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.
Liquid chromatography coupled to mass spectrometry is the most common approach because it combines a retention time with a mass measurement. A chromatographic peak alone cannot establish which peptide is present, so mass determination or amino acid analysis is used as an orthogonal confirmation alongside the separation.
This depends on buffer, pH, and concentration, and published stability data for this peptide are limited. In practice laboratories work through a refrigerated solution within a few weeks and discard samples that show cloudiness or visible particles. Freezing and thawing repeatedly is generally discouraged.
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.