alpha-MSH is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-11-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms add to total mass |
| Molecular mass | About 1024 daltons | Calculated for the free base |
| Structural class | Cyclic heptapeptide | Contains D-phenylalanine and norleucine |
| Parent hormone | Alpha-melanocyte-stimulating hormone | Endogenous tridecapeptide of 13 residues |
| Receptor profile | Non-selective melanocortin agonist | Interacts with MC1R, MC3R, MC4R and MC5R |
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.
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 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.
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.
=== Impact of pregnancy === During pregnancy, the ovaries and the placenta produce estrogen and progesterone. These hormones stimulate the 15 to 20 lobes of the milk-secreting glands in the breasts to develop. Women who experience multiple pregnancies repeatedly stretch the skin envelope during engorgement while lactating. As a woman's breasts change in size during repeated pregnancies, the size of her breasts change as her mammary glands are engorged with milk and as she gains and loses weight with each pregnancy. In addition, when milk production stops (usually as a child is weaned), the voluminous mammary glands diminish in volume, but they still add bulk and firmness to the breast. A 2010 review found that weight gain during pregnancy and breastfeeding were not significant risk factors for ptosis.
Matrix Biology is a peer-reviewed scientific journal in the field of matrix biology. The journal is published 8 times per year by Elsevier. The journal was established in 1981 as Collagen and Related Research and renamed to Matrix: Collagen and Related Research in 1988, before obtaining its current name in 1994. It is an official journal of the American Society for Matrix Biology and the International Society for Matrix Biology. The current editor-in-chief is Renato V. Iozzo (Thomas Jefferson University).
== References == Courtnall, Roy; Johnson, Chris (1999). The Art of Violin Making. London: Robert Hale. ISBN 0-7090-5876-4. Patrick Spielman. Gluing and Clamping: A Woodworker's Handbook. Sterling Publishing, 1986. ISBN 0-8069-6274-7 Weisshaar, Hans; Shipman, Margaret (1988). Violin Restoration. Los Angeles: Weisshaar~Shipman. ISBN 0-9621861-0-4.
Sources: en.wikipedia.org
Carvedilol is both a non-selective β-adrenergic receptor antagonist (β1, β2) and an α-adrenergic receptor antagonist (α1). The S(–) enantiomer accounts for the beta-blocking activity whereas the S(–) and R(+) enantiomers have alpha-blocking activity. The affinity (Ki) of carvedilol for the β-adrenergic receptors is 0.32 nM for the human β1-adrenergic receptor and 0.13 to 0.40 nM for the β2-adrenergic receptor. Using rat proteins, carvedilol has shown affinity for a variety of targets including the β1-adrenergic receptor, β2-adrenergic receptor, α1-adrenergic receptor, α2-adrenergic receptor, 5-HT1A receptor, 5-HT2 receptor, H1 receptor, D2 receptor, μ-opioid receptor, veratridine site of voltage-gated sodium channels, serotonin transporter, norepinephrine transporter, and dopamine transporter. It is an antagonist of the human 5-HT2A receptors with moderate affinity, although it is unclear if this is significant for its pharmacological actions given its much stronger activity at adrenergic receptors. Carvedilol reversibly binds to β-adrenergic receptors on cardiac myocytes. Inhibition of these receptors prevents a response to the sympathetic nervous system, leading to decreased heart rate and contractility. This action is beneficial in heart failure patients where the sympathetic nervous system is activated as a compensatory mechanism. Carvedilol blockade of α1-adrenergic receptors causes vasodilation of blood vessels. This inhibition leads to decreased peripheral vascular resistance and an antihypertensive effect.
==== Native Hawaiian or other Pacific Islander ==== The obesity rate for Native Hawaiian or other Pacific Islander adults (over 30 BMI) in the US in 2015 was 33.4%. No breakdown by sex was given for Native Hawaiian or other Pacific Islander adults in the CDC figures.
== Science and technology == Rational polynomial coefficient Reactive Plastic Curtain, a carbon-dioxide-absorbing device used in some rebreather breathing sets Regional Playback Control, a regional lockout technology for DVDs Remote procedure call, an inter-process communication technique in networked computing Open Network Computing Remote Procedure Call, IETF RPC, a.k.a. "Sun RPC" DCE/RPC, for Distributed Computing Environment by Open Software Foundation JSON-RPC, a "JSON encoded" variant XML-RPC, an "XML encoded" variant Resistive plate chamber, a simple type of particle detector used in experimental particle physics Reversed-phase chromatography, a chemistry technique Acorn Risc PC Rocket Pod Container, the interchangeable containers used to transport and launch missiles for use with the M270 Multiple Launch Rocket System Rotary phase converter, an electrical machine that converts power from one polyphase system (including frequency) to another, converting through rotary motion.
Sources: en.wikipedia.org
In arguing that West Germany was not "Americanized" after the war, Logemann joins a long debate about American consumer capitalism's power, sweep, and depth of influence in the developed world through the second half of the twentieth century. In pointed contrast to Reinhold Wagnleitner's Coca-colonization and the Cold War (1994) and Victoria de Grazia's Irresistible Empire (2005), Logemann argues that, for all the noisy commentary, pro and con, about postwar Americanization, West Germans shaped their version of the affluent society according to deeply held and distinctly un-American values. Rather than a sweeping homogenization of the developed world, postwar affluence ran along "different paths to consumer modernity" ... Instead of the "consumer-as-citizen" (whom Lizabeth Cohen, in The Consumer's Republic [2003], defined as the main social type in postwar America), West Germans promoted the social consumer who practiced "public consumption," which Logemann defines as "the provision of publicly funded alternatives to private consumer goods and services in areas ranging from housing to transportation or entertainment" (p. 5). The Freakonomics Radio podcast episode "How the Supermarket Helped America Win the Cold War (Ep. 386)" explores the impact that the supermarket had and has on American culture, including the depth of policy decisions by the US Government that impacted agriculture, as well as serving a propaganda weapon against the Soviet Union.
is not the same as the one mentioned before where it refers to the width of the spectrum. The shift is usually very small (3×10−5 cm−1 ms−1 for near-IR diode laser) and the shift-to-width ratio is of the order of 10−4.
Peptides is a monthly peer-reviewed scientific journal covering the biochemistry, neurochemistry, pharmacology, and biological functions of peptides. It was established in 1980 and is published by Elsevier. The editor-in-chief is Karl-Heinz Herzig (University of Oulu).
Sources: en.wikipedia.org
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.
Melanotan-1, also called afamelanotide, is a linear analogue with greater selectivity for MC1R and has received approval in some jurisdictions for a specific photosensitivity disorder. Melanotan-2 is cyclic, less selective, and reaches central receptors more readily. The two are often confused in online discussion despite different pharmacology and regulatory status.
Alpha-MSH is an endogenous tridecapeptide derived from pro-opiomelanocortin. Melanotan-2 reproduces its core receptor-binding sequence inside a shortened, stabilised ring. The result is a molecule with a longer effective half-life and higher potency than the parent hormone.
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.