MC1R comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-07-17. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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 | 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 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
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 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.
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.
HITS-CLIP (High-throughput sequencing of RNA isolated by crosslinking immunoprecipitation or CLIP-seq) PAR-CLIP (Photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation) iCLIP (Individual nucleotide-resolution cross-linking and immunoprecipitation) eCLIP (Enhanced cross-linking and immunoprecipitation followed by high-throughput sequencing) sCLIP (Simple cross-linking and immunoprecipitation)
== Ionic kosmotropes == Ionic kosmotropes tend to be small or have high charge density. Some ionic kosmotropes are CO2−3, SO2−4, HPO2−4, Mg2+, Li+, Zn2+ and Al3+. Large ions or ions with low charge density (such as Br−, I−, K+, Cs+) instead act as chaotropes. Kosmotropic anions are more polarizable and hydrate more strongly than kosmotropic cations of the same charge density. A scale can be established if one refers to the Hofmeister series or looks up the free energy of hydrogen bonding (
=== Dinoflagellates in the Adriatic Sea === The marine dinoflagellates: Prorocentrum micans, Lingulodinium polyedra, Gymnodinium sp., and Alexandrium tamarense, were collected from the Adriatic Sea during red-tide blooms and their 4-methyl sterol content was investigated. Dinosterol is the major component in P. micans, L. polyedra, and Gymnodinium strains, suggesting that dinosterol is a good biomarker because of its high abundance in most of the analyzed dinoflagellates.
Sources: en.wikipedia.org
Abdominal pain Anxiety Panic attacks Depression Piloerection (goose bumps) Inability to enjoy daily activities Muscle and joint pain Nausea Vomiting Runny nose and excessive secretion of tears Sweating In the clinical setting, excessive secretion of tears, yawning, and dilation of pupils are helpful presentations in diagnosing opioid withdrawal. Hydromorphone is a rapid-acting painkiller; however, some formulations may last up to several hours. Patients who stop taking this drug abruptly may experience withdrawal symptoms, which may start within hours of taking the last dose of hydromorphone, and last up to several weeks. Withdrawal symptoms in people who stopped taking the opioid may be managed by using opioids or non-opioid adjuncts. Methadone is an opioid commonly used for this kind of therapy. However, the selection of therapy should be tailored to each specific person. Methadone also is used for detoxification in people who have opiate addiction, such as heroin or drugs similar to morphine. It may be given orally or intramuscularly. There is controversy regarding whether any opioid (such as methadone) should be included in the treatment of opioid withdrawal symptoms, since these agents also may cause relapse when therapy is suspended. Clonidine is a non-opioid adjunct which may be used in situations where opioid use is not desired, such as in patients with high blood pressure.
=== Europe === Dihydromorphine is regulated in the same fashion as morphine in Germany under the BtMG, Austrian SMG, and Swiss BtMG, where it is still used as an analgesic. The drug was invented in Germany in 1900 and marketed shortly thereafter. It is often used in Patient Controlled Analgesia units.
In 2007, Hetero commissioned and established Asia’s largest Special Economic Zone (SEZ) for API manufacturing in Visakhapatnam, Visakhapatnam district Andhra Pradesh. The scale of the infrastructure provided by the complex enabled Hetero to pursue its ambitions as a global bulk pharmaceutical supplier.
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.
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.