cyclic heptapeptide 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.
Last reviewed on 2025-10-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For the lyophilised powder, desiccated |
| Storage form | Sealed vial, protected from light | Amber glass or foil-wrapped containers |
| Reconstituted stability | Short, refrigerate | Degradation accelerates in solution |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Purity assessment plus identity confirmation |
| Common synonyms | Melanotan II, MT-II | Also written melanotan-2 |
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
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.
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.
Phage display libraries of 109 randomized sequences are used to screen for Affimer proteins that exhibit high-specificity binding to the target protein with binding affinities in the nM range. The ability to direct in vitro screening techniques allows the identification of specific, high affinity Affimers. In vitro screening and development also mean that the target space for Affimers is not limited by the animal immune system. Affimers are generated using recombinant systems, so their generation is more rapid and reproducible compared to the production of polyclonal antibodies. Multimeric forms Affimers have been generated and shown to yield titres in the range of 200–400 mg/L under small-scale culture using bacterial host systems. Multimeric forms of Affimers with the same target specificity provide avidity effects in target binding. Many different tags and fusion proteins, such as fluorophores, single-stranded DNA, His, and c-Myc tags can be conjugated to Affimers. Specific cysteine residues can be introduced to the protein to allow thiol chemistry to uniformly orient Affimers on a solid support eg ELISA plates. This flexible functionalisation of the Affimer molecule allows functionality across multiple applications and assay formats.
Business biomimetics is the latest development in the application of biomimetics. Specifically it applies principles and practice from biological systems to business strategy, process, organization design, and strategic thinking. It has been successfully used by a range of industries in FMCG, defense, central government, packaging, and business services. Based on the work by Phil Richardson at the University of Bath the approach was launched at the House of Lords in May 2009. Generally, biometrics is used as a creativity technique that studies biological prototypes to get ideas for engineering solutions. In chemistry, a biomimetic synthesis is a chemical synthesis inspired by biochemical processes. Another, more recent meaning of the term bionics refers to merging organism and machine. This approach results in a hybrid system combining biological and engineering parts, which can also be referred as a cybernetic organism (cyborg). Practical realization of this was demonstrated in Kevin Warwick's implant experiments bringing about ultrasound input via his own nervous system.
Usually, a set of individually designed oligonucleotides is made on automated solid-phase synthesizers, purified and then connected by specific annealing and standard ligation or polymerase reactions. To improve specificity of oligonucleotide annealing, the synthesis step relies on a set of thermostable DNA ligase and polymerase enzymes. To date, several methods for gene synthesis have been described, such as the ligation of phosphorylated overlapping oligonucleotides, the Fok I method and a modified form of ligase chain reaction for gene synthesis. Additionally, several PCR assembly approaches have been described. They usually employ oligonucleotides of 40-50 nucleotides length that overlap each other. These oligonucleotides are designed to cover most of the sequence of both strands, and the full-length molecule is generated progressively by overlap extension (OE) PCR, thermodynamically balanced inside-out (TBIO) PCR or combined approaches. The most commonly synthesized genes range in size from 600 to 1,200 bp although much longer genes have been made by connecting previously assembled fragments of under 1,000 bp. In this size range it is necessary to test several candidate clones confirming the sequence of the cloned synthetic gene by automated sequencing methods.
Inspissation (literally meaning "thickening") is the process of increasing the viscosity of a fluid, or even of causing a fluid to solidify, typically by dehydration or otherwise reducing its content of solvents. The term also has been applied to coagulation by heating of some substances such as albumens, or to cooling some substances such as solutions of gelatin or agar. Some forms of inspissation may be reversed by re-introducing solvent, such as by adding water to molasses or to gum arabic; in other forms, its resistance to flow may include cross-linking or mutual adhesion of its component particles or molecules, in ways that prevent their dissolving again, such as in the irreversible setting or gelling of some kinds of rubber latex, egg-white, adhesives, or coagulation of blood.
36. Georgian Med News. 2006 Apr;(133):111-5. Anti-aging peptide bioregulators induce reactivation of chromatin. Lezhava T(1), Monaselidze J, Kadotani T, Dvalishvili N, Buadze T. Author information: (1)Tbilisi State University. The effect of synthetic peptide bioregulators (Epitalon, Livagen and Vilon) on structural and facultative heterochromatin of cultivated lymphocytes have been studied among old (75-88yr.) people. The data obtained indicate that epitalon, livagen and vilon: 1) activate synthetic processes, caused by reactivation of ribosomal genes as a result of deheterochromatinization (decondensation) of nucleolus organizer regions; 2) induce unrolling (deheterochromatinization) of total heterochromatin; 3) release genes repressed by heterochromatinization (condensation) of euchromatic regions forming facultative heterochromatin; 4) epitalon and livagen induce deheterochromatinization (decondensation) of pericentromeric structural heterochromatin of the chromosomes1 and 9. However, vilon does not induce deheterochromatinization of pericentromeric structural heterochromatin. These results indicate that peptide bioregulators Epitalon, Livagen and Vilon cause activation (deheterochromatinization) of chromatin in lymphocytes of old individuals.
Sources: en.wikipedia.org
Uranium-233 (233U or U-233) is a fissile isotope of uranium that is bred from thorium-232 as part of the thorium fuel cycle. Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel. It has been used successfully in experimental nuclear reactors and has been proposed for much wider use as a nuclear fuel. It decays primarily by alpha emission, with a half-life of about 159,200 years, and is part of the neptunium decay chain. Uranium-233 is produced by the neutron irradiation of thorium-232. When thorium-232 absorbs a neutron, it becomes thorium-233, which has a half-life of about 22 minutes. Thorium-233 decays into protactinium-233 through beta decay. Protactinium-233 has a longer half-life of about 27 days to further decay into uranium-233; some proposed molten salt reactor designs attempt to physically isolate the protactinium from further neutron capture before beta decay can occur, to maintain the neutron economy. 233U usually fissions on neutron absorption, but sometimes retains the neutron, becoming uranium-234. At a neutron energy of 0.0253 eV, JENDL-4.0 data give capture-to-fission ratios of about 0.085 for uranium-233, 0.169 for uranium-235 and 0.363 for plutonium-239.
vildagliptin (Galvus) EU Approved 2008 sitagliptin (Januvia) FDA approved Oct 2006 saxagliptin (Onglyza) FDA Approved July 2009 linagliptin (Tradjenta) FDA Approved May 2, 2011 alogliptin septagliptin teneligliptin gemigliptin (Zemiglo) DPP-4 inhibitors lowered hemoglobin A1C values by 0.74%, comparable to other antidiabetic drugs. A result in one RCT comprising 206 patients aged 65 or older (mean baseline HgbA1c of 7.8%) receiving either 50 or 100 mg/d of sitagliptin was shown to reduce HbA1c by 0.7% (combined result of both doses). A combined result of 5 RCTs enlisting a total of 279 patients aged 65 or older (mean baseline HbA1c of 8%) receiving 5 mg/d of saxagliptin was shown to reduce HbA1c by 0.73%. A combined result of 5 RCTs enlisting a total of 238 patients aged 65 or older (mean baseline HbA1c of 8.6%) receiving 100 mg/d of vildagliptin was shown to reduce HbA1c by 1.2%. Another set of 6 combined RCTs involving alogliptin (approved by FDA in 2013) was shown to reduce HbA1c by 0.73% in 455 patients aged 65 or older who received 12.5 or 25 mg/d of the medication.
=== Bone mineral density === Bone mineral density (BMD) is a measure commonly used to quantify bone health. A lower BMD value indicates an increased risk of an osteoporosis or a fracture. There is a large range of factors influencing BMD. Protein consumption has shown to be beneficial for bone density by providing amino acid substrates necessary for bone matrix formation. It is also thought that blood concentration of the bone formation stimulant, Insulin-like Growth Factor-I (IGF-I), is increased from high protein consumption and parathyroid hormone (PTH), a bone resorption stimulant, is decreased. Although protein has shown to be beneficial for increasing bone mass, or bone mineral density, there is no significant association between protein intake and fracture incidence. In other words, a low BMD can be predictive of osteoporosis and increased fracture risk, but a higher BMD does not necessarily mean better bone health. High BMD is also correlated with other health issues. For example, a higher BMD has also been associated with increased risk of breast cancer.
== Finite elasticity == The elastic behavior of objects that undergo finite deformations has been described using a number of models, such as Cauchy elastic material models, Hypoelastic material models, and Hyperelastic material models. The deformation gradient (F) is the primary deformation measure used in finite strain theory.
Following months of rumours and investigations, on 13 August 2013, Corcoran, along with the Essendon Football Club, senior coach James Hird, senior assistant coach Mark Thompson and club doctor Bruce Reid was charged by the AFL with bringing the game into disrepute in relation to the supplements program at the club in 2011 and 2012. The club was given 14 days to consider the charges and faced an AFL Commission hearing on 26 August 2013. On 27 August 2013, Corcoran was banned for six months with two months of that time suspended for a period of two years; effectively a four-month ban. He cannot work with any AFL club in any capacity during that period.
Sources: en.wikipedia.org
=== Music === Musician David Bowie described himself as Jungian in his relationship to dreams and the unconscious. Bowie sang of Jung on his album Aladdin Sane (a pun on "a lad insane") and attended the exhibition of The Red Book in New York with artist Tony Oursler, who described Bowie as "reading and speaking of the psychoanalyst with passion". Bowie's 1967 song "Shadow Man" encapsulates a key Jungian concept, while in 1987 Bowie described the Glass Spiders of Never Let Me Down as Jungian mother figures around which he not only anchored a worldwide tour but also created an enormous onstage effigy. British rock band the Police released an album titled Synchronicity in 1983. The American rock band Tool was influenced by Jungian concepts in its album Ænima, the title a play on the concepts of anima and animus. In the song "Forty Six & 2", the singer seeks to become a more evolved self by exploring and overcoming his Shadow. Jung's texts influenced Argentinian musician Luis Alberto Spinetta in his 1975 conceptual album Durazno sangrando, specifically the songs "Encadenado al ánima" and "En una lejana playa del ánimus", which deal with anima and animus. Jung appeared on the front cover of The Beatles' Sgt. Pepper's Lonely Hearts Club Band. He is referenced in The Streets song the "Irony of it All" from the album Original Pirate Material. The South Korean band BTS's 2019 album Map of the Soul: Persona is based on Jung's Map of the Soul, which gives the basic principles of Jung's analytical psychology.
=== Antimicrobial packaging === Antimicrobial packaging is designed to inhibit pathogenic or spoilage microorganisms on a product surface or within the package environment. Antimicrobial compounds may be incorporated into films and coatings, immobilised on a package surface, released into the package headspace, or contained in pads, labels, and separate emitters. Studied agents include organic acids, plant-derived compounds, enzymes, bacteriocins, metal ions, nanoparticles, and synthetic antimicrobial substances. The performance of antimicrobial packaging depends on the target microorganism, active-agent concentration, release rate, temperature, food composition, storage period, and contact between the package and the product. Absorbent pads used with meat, poultry, seafood, and fresh produce can combine liquid absorption with antimicrobial substances or freshness indicators.
== Roasters == The sudden influx of coffee shops have replaced the once traditional "dabang" which were common meetings places serving a selection of customary teas. In addition to large US chains that have profited from the surge in demand for coffee, local businesses and entrepreneurs have also seized the opportunities. As of 2014 South Korea boasted 17,000 coffee shops and the capital, Seoul, had more outlets of Starbucks than any other city in the world, even New York.
=== Parts === The head of the pancreas sits within the curvature of the duodenum and wraps around the superior mesenteric artery and vein. To the right sits the descending part of the duodenum, and between these travel the superior and inferior pancreaticoduodenal arteries. Behind rest the inferior vena cava and the common bile duct. In front sit the peritoneal membrane and the transverse colon. A small uncinate process emerges from below the head, situated behind the superior mesenteric vein and sometimes artery. A pancreatic notch is a separation between the neck of the pancreas and the uncinate process. The neck of the pancreas separates the head of the pancreas, located in the curvature of the duodenum, from the body. The neck is about 2 cm (0.79 in) wide and sits in front of where the portal vein is formed. The neck lies mostly behind the pylorus of the stomach and is covered with peritoneum. The anterior superior pancreaticoduodenal artery travels in front of the neck of the pancreas. The body of the pancreas is the largest part of the pancreas and mostly lies behind the stomach, tapering along its length. The peritoneum sits on top of the body of the pancreas, and the transverse colon in front of the peritoneum. Behind the pancreas are several blood vessels, including the aorta, the splenic vein, and the left renal vein, as well as the beginning of the superior mesenteric artery.
== Neurogenesis == Laboratory studies indicate that BDNF may play a role in neurogenesis. BDNF can promote protective pathways and inhibit damaging pathways in the NSCs and NPCs that contribute to the brain's neurogenic response by enhancing cell survival. This becomes especially evident following suppression of TrkB activity. TrkB inhibition results in a 2–3 fold increase in cortical precursors displaying EGFP-positive condensed apoptotic nuclei and a 2–4 fold increase in cortical precursors that stained immunopositive for cleaved caspase-3. BDNF can also promote NSC and NPC proliferation through Akt activation and PTEN inactivation. Some studies suggest that BDNF may promote neuronal differentiation.
Sources: en.wikipedia.org
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.
Reversed-phase liquid chromatography assesses purity, while mass spectrometry confirms molecular mass and detects sequence errors. Amino acid analysis and peptide mapping add structural detail. These techniques are complementary rather than interchangeable.
It is listed as a prohibited peptide hormone by the World Anti-Doping Agency. No medicines regulator has approved it for human use. Import and sale rules vary by country.
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.