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.
This page was last updated on 2026-04-21 and is reviewed periodically as new material appears.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
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 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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms differ |
| Molecular weight | Approximately 1024 g/mol | Calculated for the free base |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and polar solvents | Poorly soluble in non-polar solvents |
| Typical storage | -20 degrees Celsius, dry, protected from light | Refers to the solid form |
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.
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.
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.
In this application, Ion-exchange resins are used to replace the magnesium and calcium ions found in hard water with sodium ions. When the resin is fresh, it contains sodium ions at its active sites. When in contact with a solution containing magnesium and calcium ions (but a low concentration of sodium ions), the magnesium and calcium ions preferentially migrate out of solution to the active sites on the resin, being replaced in solution by sodium ions. This process reaches equilibrium with a much lower concentration of magnesium and calcium ions in solution than was started with.
== Growth hormone deficiency == In a study of children with growth hormone deficiency, ibutamoren performed better than other growth hormone secretagogues at improving growth hormone levels. An ongoing study compares ibutamoren directly to injectable hGH in terms of height velocity in this population. Topline data from Phase 2 OraGrowtH210 and OraGrowtH212 Trials of LUM-201 in PGHD met all primary and secondary endpoints.
== Hong Kong usage == On 28 June 1997, Andrew Wong, President of the last Legislative Council of Hong Kong as a British crown colony, which was to be dissolved by the incoming sovereign power over Hong Kong, the People's Republic of China, and replaced by a provisional legislature, declared at the end of its last session: "In accordance with the Standing Orders of the Legislative Council, I now adjourn the Council, sine die."
Other notable variants include 6 other WHO-designated variants under investigation and Cluster 5, which emerged among mink in Denmark and resulted in a mink euthanasia campaign rendering it virtually extinct.
Sources: en.wikipedia.org
Committee on Armed Services Subcommittee on Cybersecurity Subcommittee on Emerging Threats and Capabilities Subcommittee on Seapower Committee on Commerce, Science, and Transportation Subcommittee on Space and Science (Ranking Member) Subcommittee on Communications, Media, and Broadband Subcommittee on Surface Transportation, Maritime, Freight, and Ports
=== HHV-6 receptor ligand === Mori et al. first identified the gene product gQ1, a glycoprotein unique to HHV-6, and found that it forms a complex with gH and gL glycoproteins. They believed that this heterotrimer complex served as the viral ligand for CD46. Soon thereafter, another glycoprotein named gQ2 was identified and found to be part of the gH/gL/gQ1 ligand complex, forming a heterotetramer that was positively identified as the viral CD46 ligand. The exact process of entry is not yet well understood.
=== Medications that cause or worsen myasthenia gravis === Antibiotics: In the macrolide family of antibiotics, azithromycin, telithromycin (which is no longer available in the U.S. market), and erythromycin are reported to exacerbate myasthenia gravis. In the fluoroquinolone antibiotic family, ciprofloxacin, norfloxacin, ofloxacin, and moxifloxacin are reported to exacerbate myasthenia gravis. And, In the aminoglycoside family of antibiotics, gentamicin, streptomycin, and neomycin are reported to exacerbate myasthenia gravis. The aminoglycoside tobramycin has not been reported to exacerbate myasthenia gravis and may be used in people that require aminoglycoside treatment. Because of the rarity or absent reports on their exacerbation of myasthenia gravis, the following antibiotics are considered safe to use in people with myasthenia gravis: the cephalosporin class of drugs, sulfa drugs, the tetracycline group of drugs, clindamycin, polymyxin B, and nitrofurantoin. Immune checkpoint inhibitors: Immune checkpoint inhibitors promote certain types of autoimmune responses by blocking checkpoint pathways that inhibit these responses. They are used to treat cancers that promote their own growth and spread by stimulating checkpoint pathways. These checkpoint inhibitors include pembrolizumab, nivolumab, ipilimumab, avelumab, atezolizumab, and durvalumab. From a total 5,898 people who received these drugs, 52 developed new onset myasthenia gravis and 11 had a flare of their preexisting myasthenia gravis.
==== 500–599 ==== Water Supply and Sewerage Services (Customer Service Standards) (Amendment) Regulations 1993 (S.I. 1993/500) Local Government Finance Act 1992 (Community Charge Benefits) Saving Order 1993 (S.I. 1993/502) Bovine Animals (Identification, Marking and Breeding Records) (Amendment) Order 1993 (S.I. 1993/503) Prisoner Escorts Rules 1993 (S.I. 1993/515) Prison (Amendment) Rules 1993 (S.I. 1993/516) Common Agricultural Policy (Wine) Regulations 1993 (S.I. 1993/517) Social Security Benefits (Miscellaneous Amendments) Regulations 1993 (S.I. 1993/518) Occupational and Personal Pension Schemes (Miscellaneous Amendments) Regulations 1993 (S.I. 1993/519) Local Authorities (Capital Finance) (Amendment) Regulations 1993 (S.I. 1993/520) National Health Service (General Medical and Pharmaceutical Services) (Scotland) Amendment Regulations 1993 (S.I. 1993/521) National Health Service (Charges for Drugs and Appliances) (Scotland) Amendment Regulations 1993 (S.I. 1993/522) National Health Service (Dental Services) (Miscellaneous Amendments) (Scotland) Regulations 1993 (S.I. 1993/523) National Health Service (Optical Charges and Payments) (Scotland) Amendment Regulations 1993 (S.I. 1993/524) Education (Fees and Awards) (Scotland) Amendment Regulations 1993 (S.I. 1993/525) Council Tax (Dwellings) (Scotland) Regulations 1993 (S.I. 1993/526) Council Tax (Transitional Reduction Scheme) (Scotland) Amendment (No.2) Regulations 1993 (S.I. 1993/527) Legal Aid in Contempt of Court Proceedings (Scotland) Amendment Regulations 1993 (S.I.
Snakes were both revered and worshipped and feared by early civilizations. The ancient Egyptians recorded prescribed treatments for snakebites as early as the Thirteenth Dynasty in the Brooklyn Medical Papyrus, which includes at least seven venomous species common to the region today, such as the horned vipers. In Judaism, the Nehushtan was a pole with a snake made of copper fixed upon it. The object was regarded as a divinely empowered instrument of God that could bring healing to Jews bitten by venomous snakes while they were wandering in the desert after their exodus from Egypt. Healing was said to occur by merely looking at the object as it was held up by Moses. Historically, snakebites were seen as a means of execution in some cultures. Reportedly, in Southern Han during China's Five Dynasties and Ten Kingdoms period and in India a form of capital punishment was to throw people into snake pits, leaving people to die from multiple venomous bites. According to popular belief, the Egyptian queen Cleopatra VII committed suicide by letting herself be bitten by an asp—likely an Egyptian cobra—after hearing of Mark Antony's death, while some contemporary ancient authors rather assumed a direct application of poison. Snakebite as a surreptitious form of murder has been featured in stories such as Sir Arthur Conan Doyle's The Adventure of the Speckled Band, but actual occurrences are virtually unheard of, with only a few documented cases.
Sources: en.wikipedia.org
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.
Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.
Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.