Everything below concerns cyclic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-05-09. Numbers and descriptions here follow the published literature rather than marketing material.
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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Alpha-MSH analogue with a lactam ring |
| Molecular formula | C50H69N15O9 | Commonly cited value for the neutral peptide |
| Molecular weight | 1024.18 g/mol | Calculated for the free molecule |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water, DMSO and ethanol | Dissolution in pure water is often slow |
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.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
Handling guidance for melanotan II follows general practice for small synthetic peptides rather than a product-specific monograph. Lyophilized powder is typically kept at minus twenty degrees Celsius or colder, protected from light and moisture, because warmth and humidity accelerate degradation. Once reconstituted, solutions are usually refrigerated and used within a short window, as hydrolysis and microbial growth both become concerns. Repeated freeze-thaw cycles are generally avoided. These conventions come from laboratory peptide chemistry and not from formal stability studies on this specific compound.
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.
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.
=== Signaling pathway === In SCN, there is an abundant amount of VPAC2. The presence of VPAC2 in ventrolateral side suggests that VIP signals can actually signal back to regulate VIP secreting cells. SCN has neural multiple pathways to control and modulate endocrine activity. VIP and vasopressin are both important for neurons to relay information to different targets and affect neuroendocrine function. They transmit information through such relay nuclei as the SPZ (subparaventricular zone), DMH (dorsomedial hypothalamic nucleus), MPOA (medial preoptic area) and PVN (paraventricular nucleus of hypothalamus).
== History == UK-5099 (JXL001), the earlier MPC inhibitor from which suvomipic was derived, was first described in the scientific literature by 1975. Suvomipic is under development by Pelage Pharmaceuticals. In 2025, it was reported that lab work on the drug had been ongoing for almost a decade. It originated at the University of California, Los Angeles (UCLA), with Pelage Pharmaceuticals being founded and spun out of UCLA in 2018 by three scientists at the university. These academics included Bill Lowry, Heather Christofk, and Michael Jung. The chief medical officer (CMO) of the company is Qing Yu Christina Weng. Pelage Pharmaceuticals was named after the French word for "coat of fur" and "PP405" was named after the company and the 405 freeway that goes through Los Angeles. The first human clinical trials of suvomipic started in 2023 in Orange County.
== Personal life == On 5 July 2008, Emma Griffiths married Busted member Matt Willis at Rushton Hall, Northamptonshire, after three years of dating. The wedding was featured in OK magazine. She gave birth to their first child, a daughter named Isabelle, on 20 June 2009. On 25 November 2011, the couple had a second child, a son named Ace. On 4 May 2016, Willis gave birth to their third child, a second daughter, named Trixie Grace. In an episode of Who Do You Think You Are?, Willis confirmed that she has longstanding roots in Birmingham, with her family tree being traced back to her great-great-great-grandfather, who was named James Gretton and was listed as a Horn and Hair Merchant in the census records. She also found she had Irish ancestors, a fact that came as a surprise to her. The revelations about her ancestry left her extremely uncomfortable with the actions of one, who she discovered was a violent Orangeman, but overall, she was happy to have found a connection to her more broad Irish heritage. Willis is a supporter of Aston Villa. In August 2019, Willis obtained a qualification as a maternity care assistant following her experience on the W series Delivering Babies. During the COVID-19 pandemic in March 2021, Willis and her husband completed training with St John Ambulance to act as vaccination volunteers. In May 2023, Willis was featured in the documentary, Matt Willis: Fighting Addiction. The documentary, which aired on the BBC on 17 May 2023, followed Willis and her husband as they spoke about the latter's addiction issues.
The group toured Europe and the United States in late autumn 1994. Their final studio recording was a version of "Jersey Girl" for the Tom Waits tribute album Step Right Up. Meriel Barham departed in September 1995, and the group eventually disbanded in 1996. In conjunction with the August 2020 Record Store Day release of the Japanese singles compilation Mrs. Dolphin on vinyl for the first time, Masters worked with director and Big Beautiful Bluebottle bandmate Terako Terao to make a video for "Sight of You". Guitarist Graeme Naysmith died on 4 April 2024.
Sources: en.wikipedia.org
There are 203 possible ways that the exchangeability parameters can be restricted to form sub-models of GTR, ranging from the JC69 and F81 models (where all exchangeability parameters are equal) to the SYM model and the full GTR (or REV) model (where all exchangeability parameters are free). The equilibrium base frequencies are typically treated in two different ways: 1) all
Atrocities occurred in the conflict long before France ratified the 1949 Geneva Conventions on June 28, 1951, in which such acts committed afterwards in violation of the Conventions' provisions in force became war crimes. Common Article 3 of the 1949 Geneva Conventions contains a minimum protection that only applies to humane treatment in a non-international conflict (i.e., war by a state against non-state armed groups or between non-state armed groups themselves). For the purpose of this section, however, atrocities committed before or after France's ratification of the 1949 Geneva Conventions are included.
== Applications == Macromolecular structures can be determined from protein crystal using a variety of methods, including X-ray diffraction/X-ray crystallography, cryogenic electron microscopy (CryoEM) (including electron crystallography and microcrystal electron diffraction (MicroED)), small-angle X-ray scattering, and neutron diffraction. See also Structural biology. Crystallization of proteins can also be useful in the formulation of proteins for pharmaceutical purposes. Crystallization allows for the formation and purification of many active pharmaceutical ingredients. The generating of solid particles with desired crystal form and purity is crucial for controlling the physiochemical properties (the physical and chemical characteristics of a substance, such as solubility, density, pH, and stability) of proteins.
Alpha cells producing glucagon (20% of total islet cells) Beta cells producing insulin and amylin (≈70%) PP cells (gamma cells or F cells) producing pancreatic polypeptide (<5%) Delta cells producing somatostatin (<10%) Epsilon cells producing ghrelin (<1%) It has been recognized that the cytoarchitecture of pancreatic islets differs between species. In particular, while rodent islets are characterized by a predominant proportion of insulin-producing beta cells in the core of the cluster and by scarce alpha, delta and PP cells in the periphery, human islets display alpha and beta cells in close relationship with each other throughout the cluster. The proportion of beta cells in islets varies depending on the species, in humans it is about 40–50%. In addition to endocrine cells, there are stromal cells (fibroblasts), vascular cells (endothelial cells, pericytes), immune cells (granulocytes, lymphocytes, macrophages, dendritic cells,) and neural cells. A large amount of blood flows through the islets, 5–6 mL/min per 1 g of islet. It is up to 15 times more than in exocrine tissue of the pancreas. Islets can influence each other through paracrine and autocrine communication, and beta cells are coupled electrically to six to seven other beta cells, but not to other cell types. Pancreatic islets are characterized by rich innervation and vascularization, although there are notable differences between rodent and human islets. Research indicates that the vascular density in human islets is about five times lower than in rodent islets.
Most higher education institutions in Germany are public and operated by the states. All professors are public servants. Public universities are generally held in higher esteem than their private counterparts. From 1972 through 1998, public universities were tuition-free; however, some states have since adopted low tuition fees.
Sources: en.wikipedia.org
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.
No national medicines agency has approved melanotan-2 for clinical use. Afamelanotide, a related but distinct peptide, holds a marketing authorisation in the European Union for a rare photosensitivity disorder. Melanotan-2 itself is handled as a laboratory chemical.
Its broad activity across melanocortin receptors makes it a tool for probing pigmentation, appetite and vascular signalling. Early trials recorded skin darkening and other effects that were not the original focus of the work. Those observations generated hypotheses that later studies have examined.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.