If you have been reading about LC-MS/MS 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 2026-04-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Unapproved in the US, EU and Australia | Sale and import restricted; no licensed product |
| Typical test matrices | Urine, serum, seized powder | Urinary detection window is short |
| Primary identification method | LC-MS/MS against a reference standard | High-resolution mass used for confirmation |
| Data sources in the literature | Small trials, case reports, pharmacovigilance | No registrational trial dataset exists |
| Common marketing names | Melanotan 2, MT-II, MT-2 | Label content may not match declared peptide |
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
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.
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.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
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.
The ACE has benefited the most from a thorough knowledge on the enzyme structure and its mechanism of catalysis leading to the better understanding of its role in cardiovascular pathologies and therapeutics. Accordingly, for over 30 years, the treatment of human arterial hypertension has taken advantage of ACE inhibition by active site-directed inhibitors like captopril, enalapril, lisinopril, and others. For the other oligopeptidases, especially those involved in human diseases, the existing studies are promising but not yet as developed as for the ACE. Some examples are: a) the POP of nervous tissues has been suggested to be involved in neuropsychiatric disorders, like in post-traumatic stress, depression, mania, nervous bulimia, anorexia, and schizophrenia, as reviewed in. b) NEP has been involved in cancer; c) the TOP has been involved in tuberculosis and in cancer; d) the EOPA or NUDEL/EOPA (NDEL1/EOPA gene product) has been involved in neuronal migration during the cortex formation in human embryo (lissencephaly) and neurite outgrowth in adults, as in schizophrenia. Coincidentally, an activity related to the development of nervous tissue has been suggested for POP, nevertheless not involving its proteolytic activity. The absence of an oligopeptidase in the intestine was also responsible for the decreased serum zinc levels observed in patients who have the disease Acrodermatitis Enteropathica.
Elevated levels of bile acid and inflammatory proteins linked to GERD and microaspiration suggest that these factors may lead to the development of bronchiolitis obliterans in lung transplant recipients.
== History == 2C-EF was originally named by Alexander Shulgin in his 1991 book PiHKAL (Phenethylamines I Have Known and Loved). However, he only speculated about it and never actually synthesized or tested it himself. Subsequently, 2C-EF was synthesized and tested by others such as Daniel Trachsel.
Sources: en.wikipedia.org
* The daily recommended amounts of niacin and magnesium are higher than the tolerable upper limit because, for both nutrients, the ULs identify the amounts that will not increase the risk of adverse effects when the nutrients are consumed as a serving of a dietary supplement. Magnesium supplementation above the UL may cause diarrhea. Supplementation with niacin above the UL may cause flushing of the face and a sensation of body warmth. Each country or regional regulatory agency decides on a safety margin below when symptoms occur so that the ULs may differ based on the source. EAR U.S. Estimated Average Requirements. RDA U.S. Recommended Dietary Allowances; higher for adults than children and may be even higher for pregnant or lactating women. AI U.S. Adequate Intake; AIs are established when there is insufficient information to set EARs and RDAs. PRI Population Reference Intake is the European Union equivalent of RDA; it is higher for adults than for children and maybe even higher for pregnant or lactating women. For Thiamin and Niacin, the PRIs are expressed as amounts per megajoule (239 kilocalories) of food energy consumed. Upper Limit Tolerable upper intake levels. ND ULs have not been determined. NE EARs, PRIs, or AIs have not yet been established or will not be (EU does not consider chromium an essential nutrient).
In 2013, Germany revealed the existence of their 60-person Computer Network Operation unit. The German intelligence agency, BND, announced it was seeking to hire 130 "hackers" for a new "cyber defence station" unit. In March 2013, BND president Gerhard Schindler announced that his agency had observed up to five attacks a day on government authorities, thought mainly to originate in China. He confirmed the attackers had so far only accessed data and expressed concern that the stolen information could be used as the basis of future sabotage attacks against arms manufacturers, telecommunications companies and government and military agencies. Shortly after Edward Snowden leaked details of the U.S. National Security Agency's cyber surveillance system, German Interior Minister Hans-Peter Friedrich announced that the BND would be given an additional budget of 100 million Euros to increase their cyber surveillance capability from 5% of total internet traffic in Germany to 20% of total traffic, the maximum amount allowed by German law.
=== Bead method === A common laboratory-scale mechanical method for cell disruption uses glass, ceramic, or steel beads, 0.1–2 mm (0.004–0.08 in) in diameter, mixed with a sample suspended in an aqueous solution. First developed by Tim Hopkins in the late 1970s, the sample and bead mix is subjected to high level agitation by stirring or shaking. Beads collide with the cellular sample, cracking open the cell to release the intracellular components. Unlike some other methods, mechanical shear is moderate during homogenization resulting in excellent membrane or subcellular preparations. The method, often called "bead beating", works well for all types of cellular material - from spores to animal and plant tissues. It is the most widely used method of yeast lysis, and can yield breakage of well over 50% (up to 95%). It has the advantage over other mechanical cell disruption methods of being able to disrupt very small sample sizes, process many samples at a time with no cross-contamination concerns, and does not release potentially harmful aerosols in the process. In the simplest example of the method, an equal volume of beads are added to a cell or tissue suspension in a test tube and the sample is vigorously mixed on a common laboratory vortex mixer. While processing times are slow, taking 3–10 times longer than that in specialty shaking machines, it works well for easily disrupted cells and is inexpensive.
== Prevention == Preventing recurrence of hyperkalemia typically involves reduction of dietary potassium, removal of an offending medication, and/or the addition of a diuretic (such as furosemide or hydrochlorothiazide). Sodium polystyrene sulfonate and sorbitol (combined as Kayexalate) are occasionally used on an ongoing basis to maintain lower serum levels of potassium, though the safety of long-term use of sodium polystyrene sulfonate for this purpose is not well understood. High dietary sources include meat, chicken, seafood, vegetables such as avocados, tomatoes and potatoes, fruits such as bananas, oranges and nuts.
Sources: en.wikipedia.org
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.
Reversed-phase LC-MS/MS is the usual approach for both identification and quantitation. High-resolution mass spectrometry and peptide mapping serve as confirmatory methods. Immunoassays are rarely used alone because of cross-reactivity.
Published testing of seized and purchased samples frequently reports discrepancies between declared and measured peptide content. Counter-ion content and residual solvents add further variation. Independent analysis is the only way to confirm composition.
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.