alpha-MSH analog raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-11-21. Anything still debated is marked as such rather than presented as settled.
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 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 II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Log-odds matrices based on the Dayhoff PAM model were commonly used to assess the significance of homology search results, although the BLOSUM matrices have superseded the PAM log-odds matrices in this context because the BLOSUM matrices appear to be more sensitive across a variety of evolutionary distances, unlike the PAM log-odds matrices. The Dayhoff PAM matrix was the source of the exchangeability parameters used in one of the first maximum-likelihood analyses of phylogeny that used protein data and the PAM model (or an improved version of the PAM model called DCMut) continues to be used in phylogenetics. However, the limited number of alignments used to generate the PAM model (reflecting the limited amount of sequence data available in the 1970s) almost certainly inflated the variance of some rate matrix parameters (alternatively, the proteins used to generate the PAM model could have been a non-representative set). Regardless, it is clear that the PAM model seldom has as good of a fit to most datasets as more modern empirical models (Keane et al. 2006 tested thousands of vertebrate, bacterial, and archaeal proteins and they found that the Dayhoff PAM model had the best-fit to at most <4% of the proteins). Starting in the 1990s, the rapid expansion of sequence databases due to improved sequencing technologies led to the estimation of many new empirical matrices (see for a complete list).
Singapore and Malaysia: Woodlands Train Checkpoint (Malay: Pusat Pemeriksaan Kereta Api Woodlands, Chinese: 兀兰火车关卡, Tamil: ஊட்லண்ட்ஸ் இரயில் மசாதலைச்சாவடிப): For cross-border rail passengers, Singaporean exit and Malaysian entry preclearance border controls are co-located at the Woodlands Train Checkpoint in Singapore, whilst Malaysian exit controls are located separately at Johor Bahru Sentral railway station in Malaysia. Johor Bahru – Singapore Rapid Transit System (Malay: Sistem Transit Aliran Johor Bahru–Singapura, Chinese: 新山－新加坡捷运系统, Tamil: ஜோகூர் பாரு – சிங்கப்பூர் விரைவான போக்குவரத்து அமைப்பு, RTS): The upcoming RTS connecting Singapore and Johor Bahru will feature border control preclearance both on the Singaporean side and on the Malaysian side. This will enable passengers arriving in Singapore from Malaysia or vice versa to proceed straight to their connecting transport, since the RTS will link to both the Singapore MRT system (Thomson–East Coast Line) and Johor Bahru Sentral. Unlike the preclearance systems adopted in America and Hong Kong, but similar to the United Kingdom's juxtaposed controls, this system will mitigate the need for arrival border controls on both sides of the border. Malaysia and Thailand: Padang Besar railway station (Thai: สถานีรถไฟปาดังเบซาร์, Malay: Stesen keretapi Padang Besar): The Padang Besar railway station in Padang Besar, Malaysia has co-located border control facilities for both Malaysia and Thailand. However, the station is entirely within Malaysian territory (albeit just 200 metres south of the Malaysia-Thailand border).
Victoria confronts her father, General Byng, about the town's problems, and he instructs her to start taking her Joy again and check in on Dr. Verloc at Haworth Labs, where he is working on a permanent replacement for Joy. However, her progress is halted by a strike by the lab workers, who demand that Sally be reinstated to her position in the lab. After helping suppress the strike, Victoria confronts Dr. Verloc. Realizing that Dr. Verloc has no permanent solution and is willing to let the populace die off to "sustainable" levels, Victoria resolves to cut off the town's Joy supply to wean them off the drug. In order to achieve these, she destroys both the pill allocator and water treatment plant responsible for distributing Joy throughout the town. She is arrested and thrown in jail, where she remembers how her mother was imprisoned in India for supporting Indian independence from Britain. General Byng helps her escape, and informs her about his safe house where he has stockpiled supplies and an escape boat. Shocked at her father's cowardice and willingness to abandon the town to its fate, Victoria rejects his offer and resolves to save the town. In order to permanently stop all Joy production, she demolishes Haworth Labs, narrowly escaping its destruction. The combination of the destruction of the Joy supply and the broadcast of Uncle Jack's final recording sends Wellington Wells into complete anarchy as the enraged citizens slaughter each other.
The spleen is the organ which removes damaged or misshapen red blood cells from the circulation. In thalassemia, this can lead to the spleen becoming enlarged, a condition known as splenomegaly. Slight enlargement of the spleen is not a problem, however if it becomes extreme then surgical removal of the spleen (splenectomy) may be recommended.
Sources: en.wikipedia.org
In 1959 Hahn co-founded in Berlin the Federation of German Scientists (VDW), a non-governmental organisation, which has been committed to the ideal of responsible science. The members of the Federation feel committed to taking into consideration the possible military, political, and economic implications and possibilities of atomic misuse when carrying out their scientific research and teaching. With the results of its interdisciplinary work the VDW not only addresses the general public, but also the decision-makers at all levels of politics and society. Right up to his death, Otto Hahn never tired of warning of the dangers of the nuclear arms race between the great powers and of the radioactive contamination of the planet. Lawrence Badash wrote:
=== Cell migration === Cell migration is essential for the formation of granulation tissue. The early stage of granulation tissue is dominated by a HA-rich extracellular matrix, which is regarded as a conducive environment for the migration of cells into this temporary wound matrix. HA provides an open hydrated matrix that facilitates cell migration, whereas, in the latter scenario, directed migration and control of related cell mechanisms are mediated via the specific cell interaction between HA and cell surface HA receptors. It forms links with several protein kinases associated with cell locomotion, for example, extracellular signal-regulated kinase, focal adhesion kinase, and other non-receptor tyrosine kinases. During fetal development, the migration path through which neural crest cells migrate is rich in HA. HA is closely associated with the cell migration process in granulation tissue matrix, and studies show that cell movement can be inhibited, at least partially, by HA degradation or blocking HA receptor occupancy. By providing the dynamic force to the cell, HA synthesis has also been shown to associate with cell migration. Basically, HA is synthesized at the plasma membrane and released directly into the extracellular environment. This may contribute to the hydrated microenvironment at sites of synthesis, and is essential for cell migration by facilitating cell detachment.
== Etymology == The proposed name for the toxin is U7-ctenitoxin-Pn1a. Here, 'ctenitoxin' refers to toxins found in the venom of spiders from the Ctenidae family. 'Pn' is an acronym for Phoneutria nigriventer, referring to the genus and species of the animal it was isolated from. A commonly used alternative name for U7-CNTX-Pn1a is PnTx3-5, which is an acronym for Phoneutria nigriventer Toxin 3–5. Here, 3 refers to it being part of the third toxic protein fraction that was isolated from the venom using a technique involving a combination of gel filtration and reverse phase fast protein liquid chromatography. Similarly, 5 refers to it being the fifth peptide that was separated from this fraction through reverse phase and ion-exchange high-performance liquid chromatography.
Kittens are very social and spend most of their waking hours interacting with other animals and playing on their own. Play with other kittens peaks in the third or fourth month after birth, with more solitary hunting and stalking play peaking later, at about five months. Kittens are vulnerable because they like to find dark places to hide, sometimes with fatal results if they are not watched carefully. Cats have a habit of seeking refuge under or inside cars or on top of car tires during stormy or cold weather; this often leads to broken bones, burns, heat stroke, damaged internal organs or death. Domestic kittens are commonly sent to new homes at six to eight weeks of age, but it has been suggested that being with their mother and littermates from six to twelve weeks is important for a kitten's social and behavioural development. Usually, breeders and foster/rescue homes will not sell or adopt out a kitten that is younger than twelve weeks. In many jurisdictions, it is illegal to give away kittens younger than eight weeks of age. Kittens generally reach sexual maturity at around seven months, and full "adulthood" around one year of age.
The extent to which psilocin (and by extension psilocybin) is metabolized by MAO, specifically MAO-A, is not fully clear, but has ranged from 4% to 33% in different studies based on metabolite excretion. However, circulating levels of the deaminated metabolite of psilocin are far higher than those of free unmetabolized psilocin with psilocybin administration. An early clinical study of psilocybin in combination with short-term tranylcypromine pretreatment found that tranylcypromine marginally potentiated the peripheral effects of psilocybin, including pressor effects and mydriasis, but overall did not significantly modify the psychoactive and hallucinogenic effects of the psilocybin, although some of its emotional effects were said to be reduced and some of its perceptual effects were said to be amplified. Some psychedelics are substrates of cytochrome P450 (CYP450) enzymes, for instance LSD being a substrate of CYP2D6 as well as of several other CYP450 enzymes. As such, CYP450 inhibitors may increase exposure to CYP450-substrate psychedelics such as LSD and thereby potentiate their effects as well as risks. A clinical study found that administration of LSD to people taking paroxetine, a selective serotonin reuptake inhibitor (SSRI) and strong CYP2D6 inhibitor, increased LSD exposure by about 1.5-fold. The combination was well-tolerated and did not modify the pleasant subjective effects or physiological effects of LSD, whereas negative effects of LSD, including "bad drug effect", anxiety, and nausea, were reduced.
Sources: en.wikipedia.org
=== Cookbooks === American Gastronomy: An Illustrated Portfolio of Recipes and Culinary history (1974), ISBN 978-0809283415 The Bakery Restaurant Cookbook (1980), ISBN 978-0843621952 The Chef's New Secret Cookbook (1975), ISBN 978-0809283545 The Chef's Secret Cook Book: A Practical, Personal Invitation to Classic Cookery (1971), ISBN 978-0812902136 Sears Gourmet Cooking Forum (1969)
The Lipoprotein Insulin Resistance Index (LP-IR) test is a blood test that measures insulin resistance using a composite score derived from lipoprotein particle sizes and concentrations. It is performed using nuclear magnetic resonance (NMR) spectroscopy, which analyzes six specific lipoprotein parameters in a blood sample:
== Anti-thyroid drugs == Iodine uptake against a concentration gradient is mediated by a sodium–iodine symporter and is linked to a sodium-potassium ATPase. Perchlorate and thiocyanate are drugs that can compete with iodine at this point. Compounds such as goitrin, carbimazole, methimazole, propylthiouracil can reduce thyroid hormone production by interfering with iodine oxidation.
=== Atopic dermatitis === If topical corticosteroids and moisturisers fail in the treatment of atopic dermatitis, short-term treatment with topical calcineurin inhibitors such as tacrolimus or pimecrolimus may be tried. Both tacrolimus and pimecrolimus are effective and safe to use in AD.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
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.