The short version of alpha-MSH fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-02-09. Anything still debated is marked as such rather than presented as settled.
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.
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 | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
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.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
The peer-reviewed record is dominated by small early-phase studies, case reports and pharmacovigilance summaries rather than large randomised trials. Papers typically examine tanning response, receptor selectivity or patterns of reported adverse events. Many note that participants obtained the peptide outside a clinical setting, which limits verification of composition and administered amount. Reported events vary widely, and causality is frequently unclear because the identity and purity of self-sourced material are unknown. Open questions include whether repeated melanocortin receptor stimulation produces cumulative effects, and how often label claims match actual content.
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
These drugs act as antagonists or inverse agonists of the 5-HT2A, α1-adrenergic, and H1 receptors, as partial agonists of the 5-HT1A receptor, and as inhibitors of the transporters. mCPP is an antagonist of the 5-HT2B receptor, an agonist of the 5-HT1A, 5-HT2C, and 5-HT3 receptors, and acts as a partial agonist of the human 5-HT2A and 5-HT2C receptors.
Transporter competition: Many GalNAc-conjugated siRNA drugs (e.g., inclisiran, givosiran, lumasiran) are taken up by hepatocytes via the asialoglycoprotein receptor (ASGPR). Co-administration of agents that saturate or alter this receptor pathway may affect hepatic delivery of the siRNA payload. Carrier protein binding: Some oligonucleotide drugs bind serum albumin or lipoproteins. Competition with highly protein-bound small molecules could alter free-drug concentrations. Indirect CYP modulation: siRNA drugs that silence transcription factors controlling CYP gene expression (e.g., silencing of PCSK9 influences LXR/SREBP pathways) may indirectly alter CYP expression in co-treated patients. On-target miRNA network perturbation: Because endogenous microRNA (miRNA) regulates the expression of drug-metabolizing enzymes and transporters, therapeutic oligonucleotides that modulate miRNA activity can produce secondary DDIs via altered enzyme expression rather than direct enzyme binding.
Avoiding smoking Cutting down on fats to help reduce the amount of plaque buildup Eating a healthy diet, including plenty of fruits and vegetables Limiting sodium in the diet, thereby reducing blood pressure Exercising regularly Moderating intake of alcohol, stimulants, sympathomimetics, etc. Maintaining a healthy weight In addition, it is important to control any underlying medical conditions that may increase the risk of stroke or TIA, including:
Sources: en.wikipedia.org
Subsequent activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid), NMDA (N-methyl-D-aspartate) and kainate subtypes of ionotropic glutamate receptors follows. It is the activation of these receptors that potentiates the pain signal up the spinal cord. This idea, although true, is an oversimplification of pain transduction. A litany of other neurotransmitter and neuromodulators, such as calcitonin gene-related peptide (CGRP), adenosine triphosphate (ATP), brain-derived neurotrophic factor (BDNF), somatostatin, vasoactive intestinal peptide (VIP), galanin, and vasopressin are all synthesized and released in response to noxious stimuli. In addition to each of these regulatory factors, several other interactions between pain-transmitting neurons and other neurons in the dorsal horn have added impact on pain pathways.
The chemical compound thujone, which is present in the spirit in trace amounts, was blamed for its alleged harmful effects. By 1915, absinthe had been banned in the United States and much of Europe, including France, the Netherlands, Belgium, Switzerland, and Austria-Hungary, though it has not been demonstrated to be any more dangerous than ordinary spirits. Recent studies have shown that absinthe's psychoactive properties, apart from those attributable to its alcohol content, have been exaggerated. Absinthe's revival began in the 1990s, following the adoption of modern European Union food and beverage laws that removed long-standing barriers to its production and sale. By the early 21st century, nearly 200 brands of absinthe were being produced in a dozen countries, most notably in France, Switzerland, Austria, Germany, the Netherlands, Spain, and the Czech Republic.
== Gene == Humanin is encoded in the mitochondrial genome by the 16S ribosomal RNA gene, MT-RNR2. Multiple paralogs are found in the nuclear genome (due to nuclear mitochondrial DNA segments) and are named MTRNR2L followed by a number. It is not known whether these paralogous isoforms are completely unexpressed.
Sources: en.wikipedia.org
An analogue, asarone, is more potent than myristicin, elemicin, or safrole in producing hypnotic-like effects in rodents. Asarone is a natural precursor to the psychedelic amphetamine TMA-2, which is substantially more potent as a psychedelic drug than analogues like TMA and mescaline. Asarone is present in Acorus calamus and this root has limited reports of producing stimulant- and psychedelic- or LSD-like effects in humans. However, Shulgin reported that pure asarone produced no effects whatsoever at doses of up to 70 mg orally. For comparison, TMA-2 produces threshold effects at a dose of 10 mg orally and its typical or effective dose range is 20 to 40 mg orally. In accordance with Shulgin's findings, no psychoactive effects were reported and TMA-2 was not detected in a clinical series of Acorus calamus poisonings.
is found similarly. Substituting these nuclear masses into the Q-value equation, while neglecting the nearly zero antineutrino mass and the difference in electron binding energies, which is very small for high-Z atoms, we have
=== Contemporary === On Rotten Tomatoes it has a score of 38% based on 13 reviews. Audiences surveyed by CinemaScore gave the film a grade of "B+" on scale of A+ to F. Before release, Stonebridge executive Andrew Pfeiffer warned: "This kind of movie is not designed to get good reviews." The Variety reviewer credited as Bril. expressed doubts about Bosworth's star potential and assessed: "Actually, the budding star here is probably director Craig R. Baxley, who recently directed the sci-fi thriller I Come in Peace. He shows a real flair for stunt work and action sequences in both works.
== Therapeutic approaches and pharmacology == Therapeutic approaches for ERAP1 regulation rely mostly on the development of small molecule inhibitors. The most explored classes of inhibitors for ERAP1 are the catalytic or the allosteric site ones.
Sources: en.wikipedia.org
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
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.