Everything below concerns alpha-MSH. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-09. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
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.
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 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.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
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 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.
=== Nonhematopoietic roles === Erythropoietin was reported to have a range of actions beyond stimulation of erythropoiesis including vasoconstriction-dependent hypertension, stimulating angiogenesis, and promoting cell survival via activation of EPO receptors resulting in anti-apoptotic effects on ischemic tissues. However this proposal is controversial with numerous studies showing no effect. It is also inconsistent with the low levels of EPO receptors on those cells. Clinical trials in humans with ischemic heart, neural and renal tissues have not demonstrated the same benefits seen in animals. In addition some research studies have shown its neuroprotective effect on diabetic neuropathy, however these data were not confirmed in clinical trials that have been conducted on the deep peroneal, superficial peroneal, tibial and sural nerves.
Casein is amphiphilic and therefore can be used as an emulsifier. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive. The most common form of casein is sodium caseinate (historically called nutrose), which is a very efficient emulsifier. Casein is secreted into milk from mammary cells in the form of colloidal casein micelles, a type of biomolecular condensate. As a food source, casein supplies amino acids, carbohydrates, and two essential elements, calcium and phosphorus. While in animals it is only made by mammilian mammary glands (unlike some whey proteins), casein has been artificially biosynthesized. Animal-free casein proteins have been produced since at least the early 1990's using bacteria-based recombinant DNA precision fermentation genetic engineering, and has been in the process of commercialization by cellular agriculture for more than a decade. Plant-produced beta-casein has been synthesized at least since 2026.
An offshoot of the Zulu, the amaNdebele, better known to history as the Matabele, created an even larger empire under their king Mzilikazi, including large parts of the highveld and modern-day Zimbabwe.
Sources: en.wikipedia.org
=== Agah Bayar === Agah Bayar (Tamer Hassan) is an international Turkish arms dealer, who first appeared in the season eight episode "Broken Arrow". He had a brief appearance in the episode "Kill Screen" and returned in the season nine episode "Need to Know" and the season 12 episode Lost Boys. Gibbs does not like Bayar, as he seems to avoid trouble with federal agencies too easily.
Bodybuilders may supplement their diets with protein for reasons of convenience, lower cost (relative to meat and fish products), ease of preparation, and to avoid the concurrent consumption of carbohydrates and fats. Additionally, some argue that bodybuilders, by virtue of their unique training and goals, require higher-than-average quantities of protein to support maximal muscle growth. While the recommended dietary allowance is much less, Harvard Medical School points out in Harvard Health Publishing that this RDA (recommended daily allowance) is “the minimum amount you need to keep from getting sick — not the specific amount you are supposed to eat every day.” Protein supplements are sold in ready-to-drink health shakes, bars, meal replacement products (see below), bites, oats, gels and powders. Protein powders are the most popular and may have flavoring added for palatability. The powder is usually mixed with water, milk or fruit juice and is generally consumed immediately before and after exercising or in place of a meal. The sources of protein are as follows and differ in protein quality depending on their amino acid profile and digestibility:
=== Persian period === In 537–520 BCE, Zerubbabel became Yehud's governor and started work on the Second Temple, which was stopped. In 520–516 BCE, Haggai and Zechariah goaded the Judahites to resume work on the Temple. Upon completion, Joshua became its high priest. In 458–433 BCE, Ezra and Nehemiah led another group of Judahites to Yehud, with Artaxerxes's permission. Nehemiah rebuilt the temple after some unspecified disaster and removed foreign influence from the Judahite community. That said, some Judahites elected to stay in Persia, where they almost faced annihilation. This period is covered by the entirety of the Book of Ezra, Book of Nehemiah, the Book of Esther, the Book of Haggai, the Book of Zechariah, and the Book of Malachi.
Sources: en.wikipedia.org
I think most of them would rather drink weed killer than do this." He argued that the sale would stop a one-time budget problem without addressing spending, leaving a debt bomb for future generations. The legislature sided with Kennedy, and Jindal's plan dissolved.
Kennedy decided toward the end of 1871 to end his business partnership with Eddy. She had accused him in front of others of cheating at cards; it was one of several scenes she had caused between them and he walked out on her. There was a temporary reconciliation, but he was unhappy about the abandonment of head rubbing, and after a dispute between Eddy and a student over a refund was played out in the local press, he decided to go his own way. Once Kennedy and Eddy had settled their financial affairs in May 1872, she was left with $6,000. Peel writes that at this point she had already written 60 pages of Science and Health. She was renting rooms in Lynn at 9 Broad Street, when 8 Broad Street came on the market. In March 1875 she purchased it for $5,650, taking in students to pay the mortgage. It was in the attic room of this house that she completed Science and Health. Shortly after moving in, Eddy became close to another student, Daniel Spofford. He was 33 years old and married when he joined her class; he later left his wife in the hope that he might marry Eddy, but his feelings were not reciprocated. Spofford and seven other students agreed to form an association that would pay Eddy a certain amount a week if she would preach to them every Sunday. They called themselves the Christian Scientists' Association. Eddy placed a sign on 8 Broad Street: "Mary B.
=== Beyond Meat === In July 2018, A&W locations began serving Beyond Meat's vegan Beyond Burger. The chain had a shortage of the Beyond Burger in August 2018, but announced that all locations would receive stock by October 2018. In 2019 A&W expanded its Beyond Meat offerings with the release of the Beyond Meat Sausage N' Egger.
== Pathophysiology == B. burgdorferi can spread throughout the body during the course of the disease, and has been found in the skin, heart, joints, peripheral nervous system, and central nervous system. B. burgdorferi does not produce toxins. Therefore, many of the signs and symptoms of Lyme disease are a consequence of the immune response to the spirochete in those tissues. B. burgdorferi is injected into the skin by the bite of an infected Ixodes tick. Tick saliva, which accompanies the spirochete into the skin during the feeding process, contains substances that disrupt the immune response at the site of the bite. This provides a protective environment where the spirochete can establish infection. The spirochetes multiply and migrate outward within the dermis. The host inflammatory response to the bacteria in the skin causes the characteristic circular EM lesion. Neutrophils, however, which are necessary to eliminate the spirochetes from the skin, fail to appear in necessary numbers in the developing EM lesion because tick saliva inhibits neutrophil function. This allows the bacteria to survive and eventually spread throughout the body. Days to weeks following the tick bite, the spirochetes spread via the bloodstream to joints, heart, nervous system, and distant skin sites, where their presence gives rise to the variety of symptoms of the disseminated disease. The spread of B. burgdorferi is aided by the attachment of the host protease plasmin to the surface of the spirochete.
Sources: en.wikipedia.org
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.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.