This is a working overview of melanotan-2, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-22. Anything still debated is marked as such rather than presented as settled.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
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.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Exercise intolerance, Abnormal muscle fatigue (premature fatigue and/or inability to get into second wind), muscle pain (myalgia), cramping or muscle stiffness during and/or after exercise, Shortness of breath (dyspnea), or rapid breathing (tachypnea), or heavy breathing (hyperpnea), or both (exercise hyperventilation) Inappropriate rapid heart rate in response to exercise (tachycardia), Exaggerated cardiorespiratory (breath and heart rate combined) response to exercise (dyspnea/tachypnea/hyperpnea and tachycardia), Exercise-induced myogenic hyperuricemia (exercise-induced accelerated breakdown of purine nucleotides in muscle via adenylate kinase reaction and purine nucleotide cycle), Transient muscle contracture or pseudomyotonia (like a really bad cramp that can last for hours, which is myogenic and EMG silent), May have progressive muscle weakness, May have a pseudoathletic appearance (hypertrophy or pseudohypertrophy) especially of the calves, Reddish-brown urine (myoglobinuria) and considerable breakdown of muscle tissue (rhabdomyolysis). The degree of symptoms varies greatly from person to person and is dependent on the severity of enzymatic or transport protein defect. In extreme cases it can lead to rhabdomyolysis. The symptoms experienced also depend on which metabolic pathway is impaired, as different metabolic pathways produce ATP at different time periods during activity and rest, as well as the type of activity (anaerobic or aerobic) and its intensity (level of ATP consumption).
Mode I – Opening mode (a tensile stress normal to the plane of the crack), Mode II – Sliding mode (a shear stress acting parallel to the plane of the crack and perpendicular to the crack front), and Mode III – Tearing mode (a shear stress acting parallel to the plane of the crack and parallel to the crack front). When the size of the plastic zone at the crack tip is too large, elastic-plastic fracture mechanics can be used with parameters such as the J-integral or the crack tip opening displacement. The characterising parameter describes the state of the crack tip which can then be related to experimental conditions to ensure similitude. Crack growth occurs when the parameters typically exceed certain critical values. Corrosion may cause a crack to slowly grow when the stress corrosion stress intensity threshold is exceeded. Similarly, small flaws may result in crack growth when subjected to cyclic loading. Known as fatigue, it was found that for long cracks, the rate of growth is largely governed by the range of the stress intensity
== Reform and replacement == The Local Transport Act 2008 reconstituted it as the Greater Manchester Integrated Transport Authority. The integrated transport authority was replaced by Transport for Greater Manchester in 2011, which is accountable to the Greater Manchester Combined Authority.
Sources: en.wikipedia.org
253No In 1971, Bemis et al. was able to determine an isomeric level decaying with a half-life of 31 s from the decay of 257Rf. This was confirmed in 2003 at the GSI by also studying the decay of 257Rf. Further support in the same year from the FLNR appeared with a slightly higher half-life of 43.5 s, decaying by M2 gamma emission to the ground state.
Furthermore, Atracium produces a toxic metabolite called laudanosine when administered and can accumulate in patients with impaired renal function. This may lead to potential seizures and epilepsy. Thus, the dosage of the atracium should be compensated for patients with decreased renal functions. Vecuronium: Most of vecuronium's adverse effects is correlated to the drug's extension of pharmacological effects past the desired time of use. Serious adverse effects include bronchospasm, anaphylaxis, apnea, and prolonged paralysis. In some instances, hypersensitivity-associated histamine release may occur, leading to allergy-like symptoms or severe anaphylaxis in rare cases. Vecuronium has a relatively favourable safety profile when compared to pancuronium or other aminosteroid non-depolarizing drugs. Pancuronium: Pancuronium produces more significant adverse effects due to the blockade of muscarinic M2 receptors in the atria. Therefore, pancuronium may increase cardiac output, mean arterial pressure, and heart rate. To add on, patients with renal failure may experience a 30-50% decrease in plasma clearance, hence an increase in neuromuscular blockade duration. The use of pancuronium with insufficient anesthetic agents leads to morbidity and psychological trauma. Acetylcholinesterase inhibitor Donepezil: Donepezil may exhibit cardiac issues such as hypertension, cardiac arrhythmia, atrioventricular block, and bradycardia due to its vagotonia properties.
=== July === July 1 Recreational cannabis becomes legal in Connecticut and Virginia. Medical cannabis becomes legal in South Dakota. COVID-19 vaccination – Michigan Governor Gretchen Whitmer announces a month-long vaccination raffle in which residents can win a total of $5 million in cash (one grand prize of $2 million or three prizes of $1 million) and $500,000 total in college scholarships for children ages 12–17 years old (nine prizes of $55,000). The winners were drawn on August 4. July 2 – Hundreds of businesses are hit by a large-scale cyberattack, linked to the Russian REvil ransomware gang. July 2–5 – At least 233 people were killed and 618 people were injured in over 500 shootings nationwide during the Independence Day weekend. July 6 – 2021 New York City mayoral election – Eric Adams was declared the winner of the Democratic primary for mayor of New York City. July 7 – The Tampa Bay Lightning defeat the Montreal Canadiens (4-1) in the 2021 Stanley Cup Finals to win their second consecutive Stanley Cup. July 8 – Attorney Michael Avenatti is sentenced to 2.5 years in prison for attempting to extort Nike. July 9 Twitter suspensions – Twitter announces that they have suspended political commentator and nationalist Nick Fuentes. President Biden signs a 72-point executive order placing tighter regulations and scrutiny on major corporations in a variety of sectors, including Big Tech companies.
Sources: en.wikipedia.org
== Track listing == "The Death of a Dream" - 0:48 "Control Alt Delete" - 2:15 "Do You Have a Map, Because I'm Lost in Your Eyes" - 3:08 "The Girl That Destroyed Me" - 2:34 "Candycanes and Cola" - 3:06 "Audrey in Sacramento" - 2:41 "Photograph" - 2:27 "Until Her Heart Stops" - 2:56 "I'm Not Crying, My Eyeballs Are Sweating" - 2:35
Mammals regulate their core temperature using input from thermoreceptors in the hypothalamus, brain, spinal cord, internal organs, and great veins. Apart from the internal regulation of temperature, a process called allostasis can come into play that adjusts behaviour to adapt to the challenge of very hot or cold extremes (and to other challenges). These adjustments may include seeking shade and reducing activity, seeking warmer conditions and increasing activity, or huddling. Behavioral thermoregulation takes precedence over physiological thermoregulation since necessary changes can be affected more quickly and physiological thermoregulation is limited in its capacity to respond to extreme temperatures. When the core temperature falls, the blood supply to the skin is reduced by intense vasoconstriction. The blood flow to the limbs (which have a large surface area) is similarly reduced and returned to the trunk via the deep veins which lie alongside the arteries (forming venae comitantes). This acts as a counter-current exchange system that short-circuits the warmth from the arterial blood directly into the venous blood returning into the trunk, causing minimal heat loss from the extremities in cold weather. The subcutaneous limb veins are tightly constricted, not only reducing heat loss from this source but also forcing the venous blood into the counter-current system in the depths of the limbs.
17 August – SNP MSP John Mason is stripped of the party whip after a Twitter post in which he said that Israel's actions in Gaza did not amount to "genocide", something a party spokesperson describes as "completely unacceptable". 19 August – A rocket being developed by Rocket Factory Augsburg, a German company hoping to launch the UK's first space flight, explodes during a launch test at the Shetland Space Centre. The Scottish Government announces it will hold no further talks with Israeli ambassadors until there is "real progress" in resolving the Gaza conflict. Christina McKelvie, the Scottish Government's Minister for Drugs and Alcohol Policy, announces she will step back from the role while receiving treatment for secondary breast cancer. Her duties will be assumed by fellow ministers Neil Gray and Jenni Minto. 20 August – Data released by National Records of Scotland shows a 12% increase in the number of drug related deaths in Scotland during 2023, with 1,172 deaths that year, an increase of 121 from 2022. Transport Scotland announces that its pilot scheme of subsidising peak-time ScotRail fairs will end in September, having not achieved the goal of encouraging more people to travel by train rather than by road. 21 August – Aberdeen City Council announces that several hundred properties in Aberdeen affected by Reinforced Autoclaved Aerated Concrete are to be demolished and rebuilt at a cost of £150m. 22 August – Edinburgh City Council votes to introduce a tourist tax that it hopes will raise around £50m a year.
Sources: en.wikipedia.org
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.