Everything below concerns cyclic peptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-06-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
Published research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
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.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
In 2024, Andrea Cau published a study on the phylogenetics of compsognathids that called the assessment of these taxa into question. The paper recovered Sinosauropteryx, along with three other proposed compsognathids in a polytomy within basal Coelurosauria. This polytomy notably did not include Composognathus proper, which would make none of these species compsognathids. In their description of S. lingyuanensis, Qiu et al. (2025) also commented on the monophyly of Compsognathidae and revived the previously monotypic Sinosauropterygidae within Coelurosauria as a monophyletic family containing all compsognathid-like theropods from the Jehol Biota of China (Sinosauropteryx, Huadanosaurus, Huaxiagnathus and Sinocalliopteryx) in addition to Mirischia. Their phylogenetic analyses using two separate datasets are reproduced below:
Derek Malcolm of the Evening Standard felt that the movie was a "dim reworking of Fatal Attraction" and noted: "Larter as the pathological minx is the best thing about it." Obsessed opened No. 1 in its opening weekend with $28 million, and making a total domestic gross of $68 million, becoming Larter's second highest-grossing film in North-America. Larter was nominated for a third time for a Teen Choice Award when she and Beyoncé were nominated for the Teen Choice Award for Choice Movie: Rumble at the 2009 Teen Choice Awards and an MTV Movie Award for Best Fight both for Obsessed. Larter reprised her role of Claire Redfield in Resident Evil: Afterlife (2010), which was filmed in 3D and saw her character ambushed and mentally manipulated by the fictional Umbrella Corporation, before she is rescued by Alice (Milla Jovovich). Like the previous Resident Evil entries, the film received negative reviews but became a major commercial success, earning $296 million worldwide. On returning to the role of Claire, Larter told JoBlo.com: "I guess people liked me as her... I'm excited that they brought me back... to work with the man [Paul W. S. Anderson] who really created this world and this vision was what excited me about joining this next installment". In 2010, Larter appeared as the title character in a short film for Absolut Vodka entitled "Lemon Drop". After the release of Afterlife, Larter went on hiatus to focus on her family.
Later it was shown in ab initio calculations with the high level of accuracy that the Rf atom has the ground state with the 6d2 7s2 valence configuration and the low-lying excited 6d1 7s2 7p1 state with the excitation energy of only 0.3–0.5 eV. In an analogous manner to zirconium and hafnium, rutherfordium is projected to form a very stable, refractory oxide, RfO2. It reacts with halogens to form tetrahalides, RfX4, which hydrolyze on contact with water to form oxyhalides RfOX2. The tetrahalides are volatile solids existing as monomeric tetrahedral molecules in the vapor phase. In the aqueous phase, the Rf4+ ion hydrolyzes less than titanium(IV) and to a similar extent as zirconium and hafnium, resulting in the RfO2+ ion. Treatment of the halides with halide ions promotes the formation of complex ions. The use of chloride and bromide ions produces the hexahalide complexes RfCl2−6 and RfBr2−6. For the fluoride complexes, zirconium and hafnium tend to form hepta- and octa- complexes. Thus, for the larger rutherfordium ion, the complexes RfF2−6, RfF3−7 and RfF4−8 are possible.
==== Insects ==== Freeze-drying is used extensively to preserve insects for the purposes of consumption. Whole freeze-dried insects are sold as exotic pet food, bird feed, fish bait, and increasingly for human consumption. Powdered freeze-dried insects are used as a protein base in animal feeds, and in some markets, as a nutritional supplement for human use. Farmed insects are generally used for all of the aforementioned purposes versus harvesting wild insects, except in the case of grasshoppers which are often harvested out of field crops.
and encode amino acids by recoding the amino acids using the six categories proposed by Margaret Dayhoff. Reduced amino acid alphabets are viewed as a way to reduce the impact of compositional variation and saturation. Importantly, evolutionary patterns can vary among genomic regions and thus different genomic regions can fit with different substitution models. Actually, ignoring heterogeneous evolutionary patterns along sequences can lead to biases in the estimation of evolutionary parameters, including the Ka/Ks ratio. In this regard, the use of mixture models in phylogenentic frameworks is convenient to better mimic the molecular evolution observed in real data.
Sources: en.wikipedia.org
By contrast, a Scandinavian etymology is relevant given the old Scandinavian höfn (genitive hafnar) or hafn meaning 'natural harbour' or 'haven' and the phonetic evolution of the term étrave which is assuredly of Scandinavian origin is also attested in similar forms such as estable and probably dates back to the ancient Scandinavian stafn.
However, p21 can also be induced independently of p53 during processes such as differentiation, development, and in response to serum stimulation. p21 (WAF1) binds to cyclin-CDK complexes (notably CDK2, CDK1, CDK4, and CDK6), inhibiting their activity and blocking the G1/S transition. This inhibition enforces a cell cycle pause that allows DNA repair to occur. In cells with functional p53, p21 is upregulated in response to DNA damage, ensuring this checkpoint control. In contrast, p53 mutations impair p21 induction and compromise this control. In human embryonic stem cells (hESCs), although p21 mRNA is upregulated following DNA damage, the protein is not detectable. This reflects a nonfunctional p53-p21 axis at the G1/S checkpoint. This discrepancy is largely due to post-transcriptional repression, particularly by the miR-302 family of microRNAs, which inhibit p21 translation. Although p53 binds the CDKN1A promoter in hESCs, it does not regulate miR-302, which is constitutively expressed and suppresses p21 expression. The p53 pathway is interconnected with the RB1 pathway via p14^ARF, which links the regulation of these key tumor suppressors. p53 expression can be induced by UV radiation, which also causes DNA damage. In this context, p53 activation can initiate processes that lead to melanin production and tanning.
Romania terminated its mission in Iraq and withdrew its last troops on 24 July 2009, among the last countries to do so. The frigate the Regele Ferdinand participated in the 2011 military intervention in Libya. In December 2011, the Romanian Senate unanimously adopted the draft law ratifying the Romania-United States agreement signed in September of the same year that would allow the establishment and operation of a US land-based ballistic missile defence system in Romania as part of NATO's efforts to build a continental missile shield. The Aegis Ashore missile system based at Deveslu became operational in 2016. In 2024, construction work started on expanding the Mihail Kogălniceanu Air Base (RoAF 57th Air Base). The air base is set to become the largest NATO base in Europe after the implementation of a project spanning 20 years.
== Research == Ogston studied potentiometric titration of amino acids in non-aqueous solvents. He was particularly interested in sinovial fluid, and fibrous proteins. More generally, he worked on the use of physico-chemical methods to study the size, weight, and structure of molecules, such as ultracentrifugation, which he applied to insulin, for example, and electrophoresis. In this context he made many improvement to equipment used for studying the physical chemistry of proteins. For example, he devised a novel type of apparatus for measuring viscosity. He made many studies of enzymes such as peroxidase and creatine phosphotransferase. He contributed to the general field of enzyme kinetics by studying activation and inhibition. He made a sceptical study of the suggestions of a repetitive structure of proteins made by Bergmann and Niemann and by Wrinch that were widely discussed in the 1940s.
Sources: en.wikipedia.org
Gonzalez became the executive chairman. In August 2024, AbbVie acquired neuroscience drugmaker Cerevel Therapeutics for $8.7 billion, in an attempt to expand its drug pipeline. In September 2024, AbbVie filed a lawsuit against BeiGene accusing it of stealing trade secrets to develop a competing therapy to treat blood and bone marrow cancers related to the growth of "B cells" after BeiGene hired a former longtime senior AbbVie scientist. In October 2024, AbbVie acquired Aliada Therapeutics for $1.4 billion to expand its neuroscience pipeline. In January 2025, AbbVie acquired Nimble Therapeutics, a Roche spinout working to develop oral peptide treatments in the autoimmune area, for $200 million. In the same month, AbbVie announced a $1.64 billion partnership with Neomorph to develop new molecular glue degraders for multiple targets across oncology and immunology, as well as a $1 billion partnership with Simcere Zaiming to develop an investigational drug candidate for multiple myeloma. In May 2025, AbbVie entered into a collaboration and license option deal with ADARx Pharmaceuticals to develop a new type of RNA technology for disease areas like neuroscience, immunology, and oncology. In August 2025, AbbVie acquired Bretisilocin, which is under development for the treatment of major depressive disorder, from Gilgamesh Pharmaceuticals in a deal worth up to $1.2 billion. In January 2026, AbbVie struck a deal with the Trump administration to invest $100 billion in its US operations over the next 10 years and lower Medicaid prices.
=== Compound applications === Molybdenum disulfide (MoS2) is used as a solid lubricant and a high-pressure high-temperature (HPHT) anti-wear agent. It forms strong films on metallic surfaces and is a common additive to HPHT greases — in the event of a catastrophic grease failure, a thin layer of molybdenum prevents contact of the lubricated parts. When combined with small amounts of cobalt, MoS2 is also used as a catalyst in the hydrodesulfurization (HDS) of petroleum. In the presence of hydrogen, this catalyst facilitates the removal of nitrogen and especially sulfur from the feedstock, which otherwise would poison downstream catalysts. HDS is one of the largest scale applications of catalysis in industry. Molybdenum oxides are important catalysts for selective oxidation of organic compounds. The production of the commodity chemicals acrylonitrile and formaldehyde relies on MoOx-based catalysts. Molybdenum disilicide (MoSi2) is an electrically conducting ceramic with primary use in heating elements operating at temperatures above 1500 °C in air. Molybdenum trioxide (MoO3) is used as an adhesive between enamels and metals. Lead molybdate (wulfenite) co-precipitated with lead chromate and lead sulfate is a bright-orange pigment used with ceramics and plastics. The molybdenum-based mixed oxides are versatile catalysts in the chemical industry. Some examples are the catalysts for the oxidation of carbon monoxide, propylene to acrolein and acrylic acid, the ammoxidation of propylene to acrylonitrile.
Russian President Vladimir Putin acknowledged that the "special military operation" was taking longer than expected but claimed the country's nuclear arsenal was preventing the conflict from escalating. As in June 2022, he made another reference to the expansion of the Russian Empire by Peter the Great. The Ukrainian General Staff claimed to have launched multiple strikes against Russian logistic lines near the cities of Berdyansk, Tokmak, Melitopol, Enerhodar, Dniprorudne, Polohy, and Vasylivka, Zaporizhia Oblast. They claimed 240 Russians were wounded and 20 pieces of military equipment were destroyed in the strikes.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
Laboratory confirmation typically combines retention time matching on a chromatographic system with mass measurement. A reference standard of known identity is needed for a meaningful comparison. Sequence-level techniques can add further confirmation.