Everything below concerns alpha-MSH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-02-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Not approved as a medicine | No marketing authorization in major jurisdictions |
| Scheduling example | Prescription-only supply in some countries | Handled as an unlicensed medicine where restricted |
| Sports classification | Prohibited peptide | Appears on anti-doping prohibited lists |
| Reported presentation | Lyophilized vial | Nominal content varies between vendors |
| Detection approach | Liquid chromatography–tandem mass spectrometry | Used in anti-doping and forensic testing |
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.
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.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
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.
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.
Noni tea Oksusu cha, traditional roasted corn tea found in Korea Olive leaf tea Oregano tea Osmanthus tea, dried flowers of the sweet olive tree, are used alone or blended with tea leaves in China. Pandan tea Patchouli tea Pennyroyal leaf, an abortifacient Pine needle tea, or tallstrunt, made from needles of pine trees Qishr, Yemeni drink with coffee husks and ginger Red clover tea Red raspberry leaf Rosa × damascena tea, in the Middle East. Roasted wheat, used in Postum, a coffee substitute Rooibos (red bush), a reddish plant used to make an infusion and grown in South Africa. In the US it is sometimes called red tea. It has many of the antioxidant characteristics of green tea, but because it does not come from tea leaves, it has no caffeine. Rose hip (often blended with hibiscus) Roselle petals (species of hibiscus; known by other names including bissau and dah), consumed in the Sahel and elsewhere Rosemary Sabah snake grass is used as a traditional herbal tea infusion in Southeast Asia. Sagebrush, California sagebrush Sage Sakurayu, Japanese herbal tea made with pickled cherry blossom petals Sassafras roots were steeped to make tea, a practice which was common among Native Americans. They were also used in the flavoring of root beer until being banned by the FDA.
Maximum continuous exertion is limited by the onset of burning sensation from lactate accumulation in muscles. Eventually, all glycogen is exhausted, and the muscle cell enters another semi-stable state. During this transition, up-regulation of the citric acid cycle due to abundance of pyruvate is reversed, and a substantial part of the ATP pool is necessarily discharged down to AMP, which allows the citric acid cycle to be sped up by some other mechanism (perhaps by the allosteric mechanism that reacts to the lower concentration of ATP, or by amplification of the residual AMPD activity by the bloated AMP pool), until ATP production is balanced with ATP consumption. AMP conversion to adenosine, excretion to the blood (as AMP and its various metabolites), further conversion to uric acid and excretion to urine becomes significant for some time, until all AMP is eliminated from the muscle cell. The muscle movements become noticeably less precise. Breathing slows down, and from this moment reacts very weakly to the load and not at all to the perceived effort. It becomes hard to rapidly increase the load on a muscle, as in McArdle's disease, and such a rapid load increase will dump even more purines into blood and urine (looking like translucent or rust-colored sharp shiny crystals and being highly irritating). The same situation would occur if blood flow to muscle cells becomes insufficient (except that somewhat less AMP is spilled over, and somewhat more of it is metabolized inside the muscle cell).
Boletus edulis, as the species epithet edulis (Latin: edible) indicates, is an edible mushroom. Italian chef and restaurateur Antonio Carluccio described it as representing "the wild mushroom par excellence", and hailed it as the most rewarding of all fungi in the kitchen for its taste and versatility. Considered a choice edible, particularly in France, Germany, Poland and Italy, it was widely written about by the Roman writers Pliny the Elder and Martial, although ranked below the esteemed Amanita caesarea. When he was served suilli instead of boleti, the disgruntled Martial wrote: sunt tibi boleti; fungos ego sumo suillos (Ep. iii. 60)("You eat the choice boletus, I have mushrooms that swine grub up.") The flavour of porcini has been described as nutty and slightly meaty, with a smooth, creamy texture, and a distinctive aroma reminiscent of sourdough. Young, small porcini are most appreciated, as the large ones often harbour maggots (insect larvae), and become slimy, soft and less tasty with age. The fruit bodies are collected by holding the stipe near the base and twisting gently. Cutting the stipe with a knife may risk the part left behind rotting and the mycelium being destroyed. Peeling and washing are not recommended. The fruit bodies are highly perishable, due largely to the high water content (around 90%), the high level of enzyme activity, and the presence of a flora of microorganisms.
As of 2008, clinical evidence for pressure immobilization using an elastic bandage was limited. It is recommended as an immediate first-aid treatment for snakebites that have occurred in Australia (due to elapids which are neurotoxic). It is not recommended for bites from non-neurotoxic snakes such as those found in North America and some other regions of the world. The British military recommends pressure immobilization in all cases where the type of snake is unknown. Pressure immobilization is intended as an immediate first-aid measure to delay the systemic spread of venom and to buy time for medical assistance to be obtained. It does not replace definitive medical treatment. The technique aims to delay the movement of venom from a bitten limb through the lymphatic system, by applying pressure to restrict lymphatic drainage and immobilizing the bitten limb to reduce the pumping action of skeletal muscles. Because lymphatic flow is driven largely by muscle movements, the limb needs to be immobilised with a splint after the pressure bandage is applied.
Any such feature constitutes an epitope. Most antigens have the potential to be bound by multiple antibodies, each of which is specific to one of the antigen's epitopes. Using the "lock and key" metaphor, the antigen can be seen as a string of keys (epitopes) each of which matches a different lock (antibody). Different antibody idiotypes, each have distinctly formed complementarity-determining regions. Antibodies may compete for binding when they recognize overlapping epitopes. Paratope — The specific part of the antibody that binds the antigen (in general, the complementarity-determining region, though sometimes framework regions may contribute). Agretope — The specific peptide sequence recognized by a major histocompatibility complex (MHC). Hapten — A small molecule that can only induce an immune response when attached to a larger carrier molecule, such as a protein. The hapten alone will not be recognized if not associated with a carrier. T-dependent antigen – Antigens that require the assistance of T cells to induce the formation of specific antibodies. T-independent antigen – Antigens that can induce the production of antibodies without the help of T cells.
Sources: en.wikipedia.org
In 1997, Mahathir strongly supported Myanmar's inclusion into ASEAN, stating that "we are going to work very hard to get Burma into ASEAN" despite international criticism and American sanctions against the military regime. Mahathir presided as ASEAN chair over Myanmar's admission, playing a key role in ensuring its membership. However, by 2003, Mahathir's stance toward Myanmar had shifted significantly, particularly following the prolonged detention of pro-democracy leader Aung San Suu Kyi. In an interview, he openly stated that if Myanmar's military government continued to refuse Suu Kyi's release, ASEAN might have to consider expelling the country. This marked the first time an ASEAN leader had raised the possibility of Myanmar's expulsion, drawing considerable international attention.
Prior to publication of the double helix structure, Watson and Crick had little direct interaction with Franklin herself. They were, however, aware of her work, more aware than she herself realised. Watson was present at a lecture, given in November 1951, where Franklin presented the two forms of the molecule, type A and type B, and discussed the position of the phosphate units on the external part of the molecule. In January 1953, Watson was shown an X-ray photograph of B-DNA (called photograph 51), by Wilkins. Wilkins had been given photograph 51 by Rosalind Franklin's PhD student Raymond Gosling. Wilkins and Gosling had worked together in the Medical Research Council's (MRC) Biophysics Unit before director John Randall appointed Franklin to take over both DNA diffraction work and guidance of Gosling's thesis. It appears that Randall did not communicate effectively with them about Franklin's appointment, contributing to confusion and friction between Wilkins and Franklin. In the middle of February 1953, Crick's thesis advisor, Max Perutz, gave Crick a copy of a report written for a Medical Research Council biophysics committee visit to King's in December 1952, containing data from the King's group, including some of Franklin's crystallographic calculations. Franklin was unaware that photograph 51 and other information had been shared with Crick and Watson. She wrote a series of three draft manuscripts, two of which included a double helical DNA backbone.
Half-Life 2: Lost Coast is an additional level for the 2004 first-person shooter game Half-Life 2. Developed by Valve, it was released on October 27, 2005, as a free download for owners of Half-Life 2 on Steam. Players control Half-Life protagonist Gordon Freeman as he travels up a coastal cliff to destroy a Combine weapon in a monastery. Lost Coast is a technology demonstration showcasing the high-dynamic-range rendering implemented in the Source engine. It was designed with environments to emphasize these effects. Lost Coast was the first Valve game with a commentary mode, in which the developers explain elements of design as the player progresses through the level. The Lost Coast level was created for Half-Life 2, but was removed from the game. It was originally going to be a level in "Highway 17" where Gordon ends up in a strange place meeting a Fisherman. As a result, it has several minor story details that were not included in Half-Life 2. It received a generally positive reception, and there was consensus among reviewers that the new features included in Lost Coast should be integrated into future games released by Valve.
==== Experimental oral formulations ==== Estradiol decanoate, estradiol cyclooctyl acetate, estradiol 3-saccharinylmethyl ether, and EC508 (estradiol 17β-(1-(4-(aminosulfonyl)benzoyl)-L-proline)) are estradiol esters and novel oral forms of estradiol that have been developed with improved properties, such as greater bioavailability and reduced first-pass effect. Estradiol decanoate and estradiol cyclooctyl acetate were studied for potential use in menopausal hormone therapy and birth control pills but were never marketed. EC508 is currently under active development for use in menopausal hormone therapy.
11β-hydroxylation of 17OHP or P4 by CYP11B1 in the adrenal cortex into 21dF or 11OHP4, respectively, 5α-reduction by SRD5A1/SRD5A2, cleavage of a side-chain (C17-C20 bond) from the steroid nucleus by 17,20-lyase activity of CYP17A1 which converts a C21 steroid to a C19 steroid, 17β-reduction by AKR1C3 (an oxo (=O) functional group in position 17β replaced to the hydroxyl (−OH) functional group), reversible 11β-reduction/oxidation of the ketone or alcohol (an oxo (=O) functional group or hydroxyl (−OH) functional group, respectively) by HSD11B1/HSD11B2. reversible 3β-reduction/oxidation of the ketone or alcohol (an oxo (=O) functional group or hydroxyl (−OH) functional group, respectively) by AKR1C2 or AKR1C4.
Sources: en.wikipedia.org
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.
The peptide is listed as prohibited in competitive sport, so laboratories develop detection methods and monitor for its presence. Its appearance in enforcement reports reflects that classification rather than any approved athletic use. Analytical work in this area focuses on identifying the molecule and its breakdown products in biological samples.
Chromatographic separation combined with mass spectrometry identifies the peptide and estimates its amount in a sample. Testing can confirm whether the expected molecule is present and at what concentration. It cannot establish how a product was manufactured or whether it meets any purity standard.
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.