Everything below concerns melanocortin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-05-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
Published research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
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.
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
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.
Ca(OH)2 + x/8 S8 → CaSx + by-products (S2O2−3, SO2−3, SO2−4) as reported in a document of the US Department of Agriculture (USDA). This reaction is poorly understood because it is vague and involves the reduction of elemental sulfur, and no reductant appears in the equation, while sulfur oxidation products are also mentioned. The initial pH of the solution imposed by poorly soluble hydrated lime is alkaline (pH = 12.5) while the final pH is in the range 11–12, typical for sulfides, which are also strong bases. When the hydrolysis of calcium sulfide is taken into account, the individual reactions for each of the by-products are:
Hallucinogen antidotes such as the atypical antipsychotics risperidone, quetiapine, and olanzapine are trip killers that are used to block the effects of mescaline and other hallucinogenic drugs. Atypical antipsychotics are serotonin 5-HT2A receptor antagonists that directly block the effects of hallucinogens. The serotonin 5-HT2A receptor antagonist ketanserin has been found to block the psychoactive effects of mescaline. Similarly, the antipsychotic chlorpromazine, which acts as both a dopamine D2 receptor antagonist and to a lesser extent as a serotonin 5-HT2A receptor antagonist, has been reported to reverse the psychoactive effects of mescaline. Other phenothiazines, such as promethazine and diethazine, have also been reported to antagonize the effects of mescaline in humans, whereas prochlorperazine was much less effective and promazine was ineffective. Barbiturates, which are GABAA receptor positive allosteric modulators, have been found to reduce the anxiety induced by mescaline.
Pentachlorophenol (PCP) is an organochlorine compound used as a pesticide and a disinfectant. First produced in the 1930s, it is marketed under many trade names. It can be found as pure PCP, or as the sodium salt of PCP, the latter of which dissolves easily in water. It can be biodegraded by some bacteria, including Sphingobium chlorophenolicum.
Hydrogen–deuterium exchange (also called H–D or H/D exchange) is a chemical reaction in which a covalently bonded hydrogen atom is replaced by a deuterium atom, or vice versa. It can be applied most easily to exchangeable protons and deuterons, where such a transformation occurs in the presence of a suitable deuterium source, without any catalyst. The use of acid, base or metal catalysts, coupled with conditions of increased temperature and pressure, can facilitate the exchange of non-exchangeable hydrogen atoms, so long as the substrate is robust to the conditions and reagents employed. This often results in perdeuteration: hydrogen-deuterium exchange of all non-exchangeable hydrogen atoms in a molecule. An example of exchangeable protons which are commonly examined in this way are the protons of the amides in the backbone of a protein. The method gives information about the solvent accessibility of various parts of the molecule, and thus the tertiary structure of the protein. The theoretical framework for understanding hydrogen exchange in proteins was first described by Kaj Ulrik Linderstrøm-Lang and he was the first to apply H/D exchange to study proteins.
Sources: en.wikipedia.org
=== Third wave (2013–2016) === According to the CDC, the third wave of the opioid epidemic began in 2013, and concluded in 2016. This wave coincided with a significant increase in overdose deaths involving synthetic opioids, particularly illegally produced fentanyl. During this period, deaths related to prescription opioids increased marginally, while heroin-related deaths remained relatively stable. The demographic affected during this wave was younger, less frequently male, and more likely to be white and rural compared to the previous waves. The third wave also witnessed an increase in opioid-related overdoses among Black and Hispanic individuals in urban areas who use drugs. The rise in fentanyl-related deaths is attributed to the fact that fentanyl is 50 to 100 times more potent than morphine, and it is often mixed into heroin or cocaine to increase potency at a low cost. Considering that Black Americans tend to consume cocaine more frequently than heroin or other prescription opioids compared to white populations, the increase in deaths is linked to the greater prevalence of fentanyl-laced cocaine.
Researchers at universities or other institutions outside of the NIH can apply for research project grants (RPGs) from the NIH. There are numerous funding mechanisms for different project types (e.g., basic research, clinical research, etc.) and career stages (e.g., early career, postdoc fellowships, etc.). The NIH regularly issues "requests for applications" (RFAs), e.g., on specific programmatic priorities or timely medical problems (such as Zika virus research in early 2016). In addition, researchers can apply for "investigator-initiated grants" whose subject is determined by the scientist. The total number of applicants has increased substantially, from about 60,000 investigators who had applied during the period from 1999 to 2003 to slightly less than 90,000 in who had applied during the period from 2011 to 2015. Due to this, the "cumulative investigator rate", that is, the likelihood that unique investigators are funded over a 5-year window, has declined from 43% to 31%. R01 grants are the most common funding mechanism and include investigator-initiated projects. The roughly 27,000 to 29,000 R01 applications had a funding success of 17-19% during 2012 though 2014. Similarly, the 13,000 to 14,000 R21 applications had a funding success of 13-14% during the same period. In FY 2016, the total number of grant applications received by the NIH was 54,220, with approximately 19% being awarded funding. Institutes have varying funding rates.
Chemolithotrophy is a type of metabolism found in prokaryotes where energy is obtained from the oxidation of inorganic compounds. These organisms can use hydrogen, reduced sulfur compounds (such as sulfide, hydrogen sulfide and thiosulfate), ferrous iron (Fe(II)) or ammonia as sources of reducing power and they gain energy from the oxidation of these compounds. These microbial processes are important in global biogeochemical cycles such as acetogenesis, nitrification and denitrification and are critical for soil fertility.
== Mechanical characteristics == While many uses of ivory are purely ornamental in nature, it often must be carved and manipulated into different shapes to achieve the desired form. Other applications, such as ivory piano keys, introduce repeated wear and surface handling of the material. It is therefore essential to consider the mechanical properties of ivory when designing alternatives. Elephant tusks are the animal's incisors, so the composition of ivory is unsurprisingly similar to that of teeth in several other mammals. It is composed of dentine, a biomineral composite constructed from collagen fibers mineralized with hydroxyapatite. This composite lends ivory the impressive mechanical properties—high stiffness, strength, hardness, and toughness—required for its use in the animal's day-to-day activities. Ivory has a measured hardness of 35 on the Vickers scale, exceeding that of bone. It also has a flexural modulus of 14 GPa, a flexural strength of 378 MPa a fracture toughness of 2.05 MPam1/2. These measured values indicate that ivory mechanically outperforms most of its most common alternatives, including celluloid plastic and polyethylene terephthalate. Ivory's mechanical properties result from the microstructure of the dentine tissue. It is thought that the structural arrangement of mineralized collagen fibers could contribute to the checkerboard-like Schreger pattern observed in polished ivory samples. This is often used as an attribute in ivory identification.
A styptic (also spelled stiptic) is a specific type of antihemorrhagic agent that works by contracting tissue to seal injured blood vessels. Styptic pencils contain astringents. A common delivery system for this is a styptic or hemostatic pencil (not to be confused with a caustic pencil). This is a short stick of medication. Anhydrous aluminium sulfate is the main ingredient and acts as a vasoconstrictor in order to disable blood flow. The stick is applied directly to the bleeding site. The high ionic strength promotes flocculation of the blood, and the astringent chemical causes local vasoconstriction. Before safety razors were invented, a styptic pencil was a standard part of a shaving kit and was used to seal shaving cuts. Some people continue to use styptic pencils for minor skin wounds from safety or electric razors. Styptic powder is used in the veterinary trade to stop bleeding from nails that are clipped too closely. This powder is generally used on animals, such as cats, dogs, and rabbits, whose vein is found in the center of the nail.
Sources: en.wikipedia.org
Actress Cherylee Houston has hypermobile EDS. She uses a wheelchair and was the first full-time disabled actress on Coronation Street. Drag queen Yvie Oddly, winner of the 11th season of RuPaul's Drag Race Eric the Actor, a regular caller to The Howard Stern Show Actress and activist Jameela Jamil Writer and actress Lena Dunham Australian singer Sia Singer Halsey YouTuber and disability rights activist Annie Elainey Miss America 2020 Camille Schrier Baroque flautist, musicologist, and broadcast classical music presenter Hannah French Deaf singer/songwriter Mandy Harvey YouTuber and disability rights activist Jessica Kellgren-Fozard Singer-songwriter, author and artist Martha Marlow Pornographic actor and writer Lorelei Lee Reality show contestant Trevor Jones, dead from the vascular form of the disorder Scrunchie creator Rommy Hunt Revson, dead from a ruptured aorta Japanese voice actress and singer Tomori Kusunoki Chaz Lucius, an American former professional ice hockey player
=== Local factors === Moisture; keeping a wound moist rather than dry makes wound healing more rapid and with less pain and less scarring Mechanical factors Oedema Ionizing radiation Faulty technique of wound closure Ischemia and necrosis Foreign bodies. Sharp, small foreign bodies can penetrate the skin leaving little surface wound but causing internal injury and internal bleeding. For a glass foreign body, "frequently, an innocent skin wound disguises the extensive nature of the injuries beneath". First-degree nerve injury requires a few hours to a few weeks to recover. If a foreign body passes by a nerve and causes first-degree nerve injury during entry, then the sensation of the foreign body or pain due to internal wounding may be delayed by a few hours to a few weeks after entry. A sudden increase in pain during the first few weeks of wound healing could be a sign of a recovered nerve reporting internal injuries rather than a newly developed infection. Low oxygen tension Perfusion
Components of the ECM are produced intracellularly by resident cells and secreted into the ECM via exocytosis. Once secreted, they then aggregate with the existing matrix. The ECM is composed of an interlocking mesh of fibrous proteins and glycosaminoglycans (GAGs).
==== Fibroblasts ==== The scarring is created by fibroblast proliferation, a process that begins with a reaction to the clot. To mend the damage, fibroblasts slowly form the collagen scar. The fibroblast proliferation is circular and cyclically, the fibroblast proliferation lays down thick, whitish collagen inside the provisional and collagen matrix, resulting in the abundant production of packed collagen on the fibers giving scars their uneven texture. Over time, the fibroblasts continue to crawl around the matrix, adjusting more fibers and, in the process, the scarring settles and becomes stiff. This fibroblast proliferation also contracts the tissue. In unwounded tissue, these fibers are not overexpressed with thick collagen and do not contract. EPF and ENF fibroblasts have been genetically traced with the Engrailed-1 genetic marker. EPFs are the primary contributors to all fibrotic outcomes after wounding. ENFs do not contribute to fibrotic outcomes.
=== Congenital cataract === In humans, a novel mutation of the COL4A1 gene coding for collagen type IV was found to be associated with autosomal dominant congenital cataract in a Chinese family. This mutation was not found in unaffected family members or in 200 unrelated controls. In this study, sequence analysis confirmed that the Gly782 amino acid residue was highly conserved. This report of a new mutation in the COL4A1 gene is the first report of a non-syndromic autosomal dominant congenital cataract that highlights an important role for collagen type IV in the physiological and optical properties of the lens.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
Only a small number of early-stage human studies have been reported, and most were limited in size and duration. No large late-stage program has established a general efficacy or safety profile. The evidence base is therefore thin compared with approved medicines.