A practical reference on alpha-MSH analog: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-10. Anything still debated is marked as such rather than presented as settled.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Alpha-MSH analogue with a lactam ring |
| Molecular formula | C50H69N15O9 | Commonly cited value for the neutral peptide |
| Molecular weight | 1024.18 g/mol | Calculated for the free molecule |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water, DMSO and ethanol | Dissolution in pure water is often slow |
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.
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.
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.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
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.
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.
=== Pyrimidine catabolism === Cytosine and uracil are converted into beta-alanine, which is further processed into malonyl-CoA, a key precursor for fatty acid synthesis and other metabolic pathways. Thymine, on the other hand, is converted into β-aminoisobutyric acid, which is then used to form methylmalonyl-CoA. The remaining carbon skeletons, such as acetyl-CoA and succinyl-CoA, can be further oxidized in the citric acid cycle. Pyrimidine degradation ultimately results in the formation of ammonium, water, and carbon dioxide. The ammonium can then enter the urea cycle, which takes place in both the cytosol and mitochondria of cells. Pyrimidine bases can also be salvaged. For example, the uracil base can be combined with ribose-1-phosphate to form uridine monophosphate (UMP). A similar reaction occurs with thymine and deoxyribose-1-phosphate. Deficiencies in enzymes involved in pyrimidine catabolism can lead to diseases such as Dihydropyrimidine dehydrogenase deficiency, which causes neurological impairments.
== History == In February 2003, Nabil Seidah and Jae Byun, a scientist at the Clinical Research Institute of Montreal in Canada, discovered a novel human proprotein convertase, the gene for which was located on the short arm of chromosome 1. Meanwhile, a lab led by Catherine Boileau at the Necker–Enfants Malades Hospital in Paris had been following families with familial hypercholesterolaemia, a genetic condition that, in 90% of cases causes coronary artery disease (FRAMINGHAM study) and in 60% of cases may lead to an early death; they had identified a mutation on chromosome 1 carried by some of these families, but had been unable to identify the relevant gene. The labs got together and by the end of the year published their work, linking mutations in the gene, now identified as PCSK9, to the condition. In their paper, they speculated that the mutations might make the gene overactive. In that same year, investigators at Rockefeller University and University of Texas Southwestern had discovered the same protein in mice, and had worked out the novel pathway that regulates LDL cholesterol in which PCSK9 is involved, and it soon became clear that the mutations identified in France led to excessive PCSK9 activity, and thus excessive removal of the LDL receptor, leaving people carrying the mutations with too much LDL cholesterol. Meanwhile, Helen H. Hobbs and Jonathan Cohen at UT-Southwestern had been studying people with very high and very low cholesterol, and had been collecting DNA samples.
Bektashism originated in Anatolia as the followers of the 13th-century scholar Bektash, who himself studied under the mystic Ahmad Yasawi, who was born in Sayram, now in southern Kazakhstan. The doctrines and rituals of the Bektashis were codified by the mystic Balım Sultan, who is considered the pīr-i thānī (“the Second Elder”) by Bektashis. It was originally founded as a Sufi movement, one of many Sufi orders within Sunni Islam. By the 16th century, the order had adopted some tenets of Twelver Shi'ism—including veneration of Ali, the cousin and son-in-law of the Islamic prophet Muhammad, and the Twelve Imams—as well as a variety of syncretic beliefs.
An index to measure gender equality in higher education programs; Quotas for leadership positions in large companies: 30% of executive managers and governing body members must be women by 2027, rising to 40% by 2030.
Sources: en.wikipedia.org
He is dressed in a bordered and turned-up, collarless tunic with close-fitting sleeves. The tunic, which reaches slightly above the knee, is belted. The pants are of the same color and have the same border. He wears gray calf boots with cruciate ligaments that run under the sole. The figure behind holds a wreath and a kind of censer, is dressed in a black belted lap jacket with tight-fitting sleeves, which is provided with a red border all around, and an ample green dress. Their hair is cut straight to the nuque, a hair style also referenced for the people of Kucha in the contemporary Chinese chronicles Jin Shu. A kneeling monk appeared next to the top left corner of the main mural, in a red robe and with ocher shorn hair, engaged in shaping a ceremonial jar with a hammer, while behind him appeared a painter wearing a tunic similar to those of the donors on the other side, but whose head only remained.
From the 17th century, and before modern developments in organic chemistry nomenclature, acetone was given many different names. They included "spirit of Saturn", which was given when it was thought to be a compound of lead and, later, "pyro-acetic spirit" and "pyro-acetic ester". Prior to the name "acetone" being coined by French chemists, it was named "mesit" (from the Greek μεσίτης, meaning mediator) by Carl Reichenbach, who also said that methyl alcohol consisted of mesit and ethyl alcohol. Names derived from mesit include mesitylene and mesityl oxide which were first synthesised from acetone. In 1839, the name "acetone" began to be used, because it was obtained from acetic acid. Unlike many compounds with the acet- prefix which have a 2-carbon chain, acetone has a 3-carbon chain. That has caused confusion because there can not be a ketone with 2 carbons. The prefix refers to acetone's relation to vinegar (acetum in Latin, also the source of the words "acid" and "acetic"), rather than its chemical structure.
== Definition == Natural uranium contains about 0.72% 235U. Depleted uranium has lower mass fractions—up to three times less—of 235U and 234U than natural uranium. Since 238U has a much longer half-life than the lighter isotopes, DU is about 40% less radioactive than natural uranium. Most of the alpha radiation comes from 238U and 234U whereas beta radiation comes from decay products 234Th and 234Pa that are formed within a few weeks. The United States Nuclear Regulatory Commission (NRC) defines depleted uranium as uranium with a percentage of the 235U isotope that is less than 0.711% by weight (see 10 CFR 40.4). The military specifications designate that the DU used by the U.S. Department of Defense (DoD) contain less than 0.3% 235U. In actuality, DoD uses only DU that contains approximately 0.2% 235U.
==== Mechanism of action ==== The mechanism of action of biguanides is not fully understood, and many mechanisms have been proposed for metformin. Biguanides do not affect the output of insulin, unlike other hypoglycemic agents such as sulfonylureas and meglitinides. Therefore, they are effective in Type 2 diabetics; and in Type 1 diabetes when used in conjunction with insulin therapy. Mainly used in Type II diabetes, metformin is considered to increase insulin sensitivity in vivo, resulting in reduced plasma glucose concentrations, increased glucose uptake, and decreased gluconeogenesis. However, in hyperinsulinemia, biguanides can lower fasting levels of insulin in plasma. Their therapeutic uses derive from their tendency to reduce gluconeogenesis in the liver, and, as a result, reduce the level of glucose in the blood. Biguanides also tend to make the cells of the body more willing to absorb glucose already present in the bloodstream, and there again reducing the level of glucose in the plasma. Biguanides have been shown to interact with copper, specifically in mitochondria, where they interfere with cell metabolism by chelating Copper in its 2+ oxidation state (Cu(II)).
=== South Ossetia === The Government of South Ossetia in Tskhinvali called for Russian help to prevent "genocide" when the Georgian bombardment began, saying that Tskhinvali was under "the most frightful fire".
Sources: en.wikipedia.org
=== Doping === PRP treatments may violate anti-doping rules. As of 2010, it was not clear whether PRP could have a systemic impact on circulating cytokine levels, affecting doping tests and whether PRP treatments had systemic anabolic effects or affect performance. In January 2011, the World Anti-Doping Agency removed intramuscular injections of PRP from its prohibitions after determining that there is a "lack of any current evidence concerning the use of these methods for purposes of performance enhancement".
After this, the June Days uprising broke out, over the course of 24–26 June, when the eastern industrial quarter of Paris, led by the worker Louis Pujol, fought the western quarter, led by general Louis-Eugène Cavaignac, who had been appointed military dictator. The socialist party was defeated and afterwards its members were deported. But the republic had been discredited and had already become unpopular with both the peasants, who were exasperated by the new land tax of 45 centimes imposed in order to fill the empty treasury, and with the bourgeoisie, who were intimidated by the power of the revolutionary clubs and disadvantaged by the economic stagnation. By the "riots" of the June Days, the working classes were also alienated from it. The Duke of Wellington wrote at this time, "France needs a Napoleon! I cannot yet see him..." The granting of universal suffrage to a society with Imperialist sympathies would benefit reactionaries, which culminated in the election of Louis-Napoléon Bonaparte as president of the republic.
Lathyrism is a condition caused by eating certain legumes of the genus Lathyrus. There are three types of lathyrism: neurolathyrism, osteolathyrism, and angiolathyrism, all of which are incurable, differing in their symptoms and in the body tissues affected. Neurolathyrism is the type associated with the consumption of legumes in the genus Lathyrus that contain the toxin oxalyldiaminopropionic acid (ODAP). ODAP ingestion results in motor neuron death. The result is paralysis and muscle atrophy of the lower limbs. Osteolathyrism, a different type of lathyrism, affects the connective tissues, not the motor neurons. Osteolathyrism results from the ingestion of Lathyrus odoratus seeds (sweet peas), and is often referred to as odoratism. It is caused by a different toxin, beta-aminopropionitrile, which affects the linking of the subunits of collagen, a major structural protein found in connective tissue. A third type of lathyrism is angiolathyrism, which is similar to osteolathyrism in its mechanism, employing the toxin beta-aminopropionitrile. The blood vessels are affected, as opposed to bone.
=== 1,400-year-old ginkgo tree at Gu Guanyin === The grounds of the Buddhist temple at Gu Guanyin in the Zhongnan Mountains feature a ginkgo tree reputed to be 1,400 years old. The tree itself is a popular tourist attraction.
=== Tolerance === Clinical research has not demonstrated drug tolerance, a reduction in wakefulness-promoting and anti-fatigue effects, as a common outcome, even with therapeutic use extending up to 40 weeks. However, long-term use can lead to tolerance in some individuals, necessitating higher doses to maintain efficacy. People with current or past substance addictions and those with a family history of addiction are at higher risk. The underlying mechanisms, which may involve dopamine and norepinephrine pathways, are not fully understood. Tolerance appears more likely with off-label use for cognitive enhancement than with therapeutic use for narcolepsy, where effectiveness does not usually diminish with prolonged treatment.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.
No national medicines agency has approved melanotan-2 for clinical use. Afamelanotide, a related but distinct peptide, holds a marketing authorisation in the European Union for a rare photosensitivity disorder. Melanotan-2 itself is handled as a laboratory chemical.
Its broad activity across melanocortin receptors makes it a tool for probing pigmentation, appetite and vascular signalling. Early trials recorded skin darkening and other effects that were not the original focus of the work. Those observations generated hypotheses that later studies have examined.
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.