This is a working overview of alpha-MSH analogue, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-21. 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.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
| 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 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.
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.
Lyophilised melanotan-2 is comparatively robust when kept dry, cold and dark, and a desiccated powder stored at minus twenty degrees Celsius or below is generally expected to retain its chemical integrity for extended periods. In solution the peptide is far less stable, with degradation proceeding through oxidation of tryptophan and histidine residues, hydrolysis adjacent to the lactam bridge, and aggregation at higher concentrations. Repeated freeze-thaw cycling accelerates loss of the parent peak. Working aliquots are therefore prepared once, held cold, and used without letting the stock return to ambient temperature.
Quality assessment of research-grade peptide rests mainly on reversed-phase high-performance liquid chromatography for purity and on mass spectrometry for identity confirmation. A single main peak above a stated threshold, commonly ninety-eight percent by peak area, is the usual release criterion applied by suppliers. Independent analyses commissioned by laboratories and consumer organisations have repeatedly reported discrepancies between label claims and measured content, including truncated sequences, residual trifluoroacetate, and lower-than-declared peptide mass. Those findings do not establish that every supplier is unreliable, but they indicate that purity figures printed on a vial are claims requiring verification rather than settled facts.
The existence of intermolecular forces was first postulated by Johannes Diderik van der Waals in 1873. However, Nobel laureate Hermann Emil Fischer developed supramolecular chemistry's philosophical roots. In 1894, Fischer suggested that enzyme–substrate interactions take the form of a "lock and key", the fundamental principles of molecular recognition and host–guest chemistry. In the early twentieth century non-covalent bonds were understood in gradually more detail, with the hydrogen bond being described by Latimer and Rodebush in 1920. With the deeper understanding of the non-covalent interactions, for example, the clear elucidation of DNA structure, chemists started to emphasize the importance of non-covalent interactions. In 1967, Charles J. Pedersen discovered crown ethers, which are ring-like structures capable of chelating certain metal ions. Then, in 1969, Jean-Marie Lehn discovered a class of molecules similar to crown ethers, called cryptands. After that, Donald J. Cram synthesized many variations to crown ethers, on top of separate molecules capable of selective interaction with certain chemicals. The three scientists were awarded the Nobel Prize in Chemistry in 1987 for "development and use of molecules with structure-specific interactions of high selectivity". In 2016, Bernard L. Feringa, Sir J. Fraser Stoddart, and Jean-Pierre Sauvage were awarded the Nobel Prize in Chemistry, "for the design and synthesis of molecular machines".
== Research == Breastfeeding research continues to assess prevalence, HIV transmission, pharmacology, costs, benefits, immunology, contraindications, and comparisons to synthetic breast milk substitutes. Factors related to the mental health of the nursing mother in the perinatal period have been studied. While cognitive behavior therapy may be the treatment of choice, medications are sometimes used. The use of therapy rather than medication reduces the infant's exposure to medication that may be transmitted through the milk. In coordination with institutional organisms, researchers are also studying the social impact of breastfeeding throughout history. Accordingly, strategies have been developed to foster the increase of the breastfeeding rates in the different countries.
=== Laser === MALDI techniques typically employ the use of UV lasers such as nitrogen lasers (337 nm) and frequency-tripled and quadrupled Nd:YAG lasers (355 nm and 266 nm respectively). Infrared laser wavelengths used for infrared MALDI include the 2.94 μm Er:YAG laser, mid-IR optical parametric oscillator, and 10.6 μm carbon dioxide laser. Although not as common, infrared lasers are used due to their softer mode of ionization. IR-MALDI also has the advantage of greater material removal (useful for biological samples), less low-mass interference, and compatibility with other matrix-free laser desorption mass spectrometry methods.
Sources: en.wikipedia.org
Embryonic Hb are expressed as early as four to six weeks of embryogenesis and disappear around the eighth week of gestation as they are replaced by fetal Hb. Embryonic Hbs include: Hb Gower-1, composed of two ζ (zeta) globins and two ε (epsilon) globins, i.e., ζ2ε2 Hb Gower-2, composed of two α globins and two ε globins (α2ε2) Hb Portland, composed of two ζ globins and two γ (gamma) globins (ζ2γ2) Fetal Hb (HbF) is produced from approximately eight weeks of gestation through birth and constitutes approximately 80 percent of Hb in the full-term neonate. It declines during the first few months of life and, in the normal state, constitutes <1 percent of total Hb by early childhood. HbF is composed of two α globins and two γ globins (α2γ2). Adult Hb (HbA) is the predominant Hb in children by six months of age and onward; it constitutes 96-97% of total Hb in individuals without a hemoglobinopathy. It is composed of two α globins and two β globins (α2β2). HbA2 is a minor adult Hb that normally accounts for approximately 2.5–3.5% of total Hb from six months of age onward. It is composed of two α globins and two δ (delta) globins (α2δ2).
==== Near-death experiences ==== A 2018 study found significant relationships between DMT experiences and near-death experiences (NDE). A 2019 large-scale study pointed that ketamine, Salvia divinorum, and DMT (and other classical psychedelic substances) may be linked to NDEs due to the semantic similarity of reports associated with the use of psychoactive compounds and NDE narratives, but the study concluded that with the current data it is neither possible to corroborate nor refute the hypothesis that the release of an endogenous ketamine-like neuroprotective agent underlies NDE phenomenology.
Various other experiments have shown that, besides bearing polymerase properties, ribozymes could have developed other kinds of evolutionarily useful catalytic activity such as synthase, ligase, or aminoacylase activities. Ribozymal aminoacylators and ribozymes with the ability to form peptide bonds might have been crucial to inventing translation. An RNA ligase, in turn, could link various components of quasispecies into one chain, beginning the process of a genome integration. An RNA with a synthase or a synthetase activity could be critical for building compartments and providing building blocks for growing RNA and protein chains as well as other types of molecules. Many examples of this kind of ribozyme are currently known, including a peptidyl transferase ribozyme, a ligase, and a nucleotide synthetase. A transaminoacylator described in 2013 has five nucleotides, which is sufficient for a trans-amino acylation reaction and makes it the smallest ribozyme that has been discovered. It supports a peptidyl-RNA synthesis that could be a precursor for the contemporary process of linking amino acids to tRNA molecules. An RNA ligase's catalytic domain, consisting of 93 nucleotides, proved to be sufficient to catalyse a linking reaction between two RNA chains. Similarly, an acyltransferase ribozyme 82 nucleotides long was sufficient to perform an acyltransfer reaction. Altogether, the results concerning the RNA ligase's catalytic domain and the acyltransferase ribozyme are in agreement with the estimated upper limit of 100 nucleotides set by the error threshold problem.
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.
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.