This is a working overview of mass spectrometry, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-06 and is reviewed periodically as new material appears.
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.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
| 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 |
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.
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.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
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.
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.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Jellyfish is very low in cholesterol and sugars, but cheap preparation can introduce undesirable amounts of heavy metals. The "sea wasp" Chironex fleckeri has been described as the world's most venomous jellyfish and is held responsible for 67 deaths, although it is difficult to identify the animal as it is almost transparent. Most stingings by C. fleckeri cause only mild symptoms. Seven other box jellies can cause a set of symptoms called Irukandji syndrome, which takes about 30 minutes to develop, and from a few hours to two weeks to disappear. Hospital treatment is usually required, and there have been a few deaths. A number of the parasitic myxozoans are commercially important pathogens in salmonid aquaculture. A Scyphozoa species – Pelagia noctiluca – and a Hydrozoa – Muggiaea atlantica – have caused repeated mass mortality in salmon farms over the years around Ireland. A loss valued at £1 million struck in November 2007, 20,000 died off Clare Island in 2013 and four fish farms collectively lost tens of thousands of salmon in September 2017.
On 3 August 2023, Move Forward MP Nakhonchai Khunnarong resigned over his criminal record, but Move Forward held Rayong 3rd district after Phongsathorn Sornpetchnarin won the by-election. On 28 September, Move Forward MP for Phitsanulok 1st district Padipat Suntiphada left the party to retain his position as First Deputy Speaker of the House of Representatives, which the opposition party is barred from holding. As sitting MPs are required to be members of political parties, Padipat joined the Fair Party on 31 October increasing that party's total seats to two. In November 2023, amid a sexual assault scandal, Move Forward expelled two MPs: Wuttiphong Thonglour of Prachinburi on 1 November and Chaiyamparwaan Munphianchit of Bangkok on 7 November. By the end of November, Chaiyamparwaan joined the Thai Progress Party as its only MP whilst Wuttiphong joined the Chart Pattana Party and increased its number of MPs to three. On 30 August 2023, the sole MP and leader of the Thai Liberal Party, Sereepisuth Temeeyaves, resigned his seat and was replaced by Mangkorn Yontrakul also from the Thai Liberal. On 7 August 2024, Move Forward was dissolved by the Constitutional Court over the party's campaign to amend Thailand's lèse-majesté laws. The dissolution accompanied five sitting party-list MPs receiving 10-year bans from politics: Pita Limjaroenrat, Chaithawat Tulathon, Apichart Sirisunthon, Bencha Saengchantra and Suthep U-on. As party-list seats, no by-elections were held and the five seats remained vacant.
== Production == Ron Shapiro – executive producer, A&R James Hunter – A&R Patrick Leonard – producer arrangements Duncan Sheik – co-producer arrangements Michele Arifty – personal assistant to Patrick Leonard Lisa Marie – representative Suzanne Ybarra – representative Moir/Marie Entertainment – representation company Jim Goodkind – legal affairs Loeb & Loeb – legal affairs Katrina Leigh – project coordinator Lynn Kowalewski – art direction Allen Hori – design Philippe McClelland – photography Technical credits
==== War poetry ==== Thomas's horror of war, foreshadowed in some of his poems of the 1930s and fuelled by his lived experience of the bombing raids and fire storms of the Blitz in London, received further expression in his poems of the war period. These include elegies for an elderly man—Among Those Killed in a Dawn Raid Was a Man Aged a Hundred (1941)—and for child victims of incendiary bombing raids in Ceremony After a Fire Raid (1944) and A Refusal to Mourn the Death, by Fire, of a Child in London (1945). They were collected in Deaths and Entrances, the fourth volume of his poetry, published in 1946. The sentiments expressed in his war poems were, according to Walford Davies, representative of "the real temper of the British people of the time—the resilience and the guts".
Peptide:N-glycosidase F, commonly referred to as PNGase F, is an amidase of the peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase class. PNGase F works by cleaving between the innermost GlcNAc and asparagine residues of high mannose, hybrid, and complex oligosaccharides from N-linked glycoproteins and glycopeptides. This results in a deaminated protein or peptide and a free glycan. PNGase F has a molecular weight of 35,500 and consists of a polypeptide chain of 314 amino acids. The optimal pH for enzyme activity is 8.6. However, the activity is stable for a wide variety of conditions and reagents. PNGase F maintains 60% activity from pH 6.0 to pH 9.5. It is able to deglycosylate in the absence of denaturants, but needs extensive incubation and larger amounts of the enzyme to cleave native proteins. Other endoglycosidases, similar to PNGase F, include endoglycosidase F1, endoglycosidase F2, endoglycosidase F3, and endoglycosidase H. These endoglycosidases have more specificity in cleavage and are less sensitive to protein conformation than PNGase F. All of these endoglycosidases, including PNGase F, can be purified from an almond emulsion or flavobacterium meningosepticum.
Sources: en.wikipedia.org
== Development and regulation in the United States == The solid filiform needle used in dry needling is regulated by the FDA as a Class II medical device described in the code titled "Sec. 880.5580 Acupuncture needle is a device intended to pierce the skin in the practice of acupuncture". Per the Food and Drug Act of 1906 and the subsequent amendments to said act, the FDA definition applies to how the needles can be marketed and does not mean that acupuncture is the only medical procedure where these needles can be used. Dry needling using such a needle contrasts with the use of a hollow hypodermic needle to inject substances such as saline solution, botox or corticosteroids to the same point. The founder of Integrative Systemic Dry Needling (ISDN), Yun-Tao Ma, has spearheaded the "dry needling" movement in the United States. Ma states, "Although ISDN originated in traditional Chinese methods, it has developed from the ancient empirical approach to become modern medical art rooted in evidence-based thinking and practice." Ma also states that, "Dry needling technique is a modern Western medical modality that is not related to traditional Chinese acupuncture in any way. Dry needling has its own theoretical concepts, terminology, needling technique, and clinical application."
When cyclopentadiene is used as the diene, the vicinal norbornene diol bicyclo[2.2.1]hept-5-ene-2,3-diol is formed after hydrolysis. The Swern oxidation to the 1,2-ketone bicyclo[2.2.1]hept-5-ene-2,3-dione proceeds (in the variant with trifluoroacetic anhydride instead of oxalyl chloride) with a yield of 73%.
Charles Miller Metzner (1931), judge on the United States District Court for the Southern District of New York and the Temporary Emergency Court of Appeals Lawrence E. Walsh (1932), independent counsel in the Iran-Contra affair; 4th United States Deputy Attorney General William Golub (1934), lawyer and advisor to Governor Nelson Rockefeller Harold Leventhal (1934), judge on the United States Court of Appeals for the District of Columbia Circuit John Slate (1935), lawyer and name partner of Skadden Arps Slate Meagher & Flom Daniel Mortimer Friedman (1937), judge of the United States Court of Appeals for the Federal Circuit, last chief judge of the United States Court of Claims, and acting solicitor general of the United States Wilfred Feinberg (1940), judge of the United States Court of Appeals for the Second Circuit Hugh H. Bownes (1941), judge of the United States Court of Appeals for the First Circuit Richard Kuh (1941), New York County district attorney and prosecutor of Lenny Bruce for obscenity Leonard I. Garth (1942), senior judge on the United States Court of Appeals for the Third Circuit Charles L. Brieant (1944), judge of the United States District Court for the Southern District of New York Jack Greenberg (1945), civil rights lawyer who argued the Brown v. Board of Education case before the United States Supreme Court Roy Cohn (1946), attorney and counsel to Sen. Joseph McCarthy Arthur Lazarus Jr. (1947), American Indian rights lawyer, argued United States v.
== Research == There are various studies researching the concept of the wounded healer, most notably that by British counselor and psychotherapist Alison Barr who studied the significance of psychological wounds on people who decide to train as counsellors or psychotherapists. Barr used a pluralistic approach to her research, with the quantitative data analyzed using descriptive and inferential statistics and the qualitative data analyzed using thematic analysis, with a grounded theory approach. An on-line questionnaire was conducted with 253 respondents. Pilot and verification studies were performed, and opportunities for further research highlighted. Barr’s results showed that 73.9% of counselors and psychotherapists have experienced one or more wounding experiences leading to career choice. She also noted the following:
Sources: en.wikipedia.org
=== Basal metabolic rate === Basal metabolic rate (BMR) is one of the main components of a person's daily energy expenditure. It is defined as the amount of energy that is expended during a given amount of time by a person at rest. This energy at rest is used to pump blood throughout the body, maintain proper brain function, break down toxins, and ensure other bodily functions. Technically speaking, BMR is the energy the body expends during the following specific conditions: immediately after waking up, while in a resting state, and after fasting for 12–14 hours. Sometimes the term Resting Metabolic Rate (RMR) is used in place of BMR, but RMR is not solely measured under the previously listed stringent conditions and it is about 10% more than BMR. The BMR is directly proportional to a person's lean body mass. In other words, the more lean body mass a person has, the higher their BMR. BMR is also affected by acute illnesses and increases with burns, fractures, infections, fevers, etc. It can be measured via direct and indirect calorimetry. However, it is also possible to approximately estimate BMR using several equations that factor in a person's age, sex, height, and weight. Some of the most popular and accurate equations used to calculate BMR are the original Harris-Benedict equations, the revised Harris-Benedict equations, and the Mifflin St. Jeor equation. The original Harris-Benedict Equations are as follows:
== Chiral chromatography == This term has become very popular and commonly used in practice. But the appropriate expression is "enantioselective chromatography". Chiral chromatography has advanced to turn into the most preferred technique for the determination of enantiomeric purity as well as separation of pure enantiomers both on analytical and preparative scale. Chiral chromatographic assay is the first step in any study pertaining to enantioselective synthesis or separation. This includes the use of techniques viz. gas chromatography (GC), high performance liquid chromatography (HPLC), chiral supercritical fluid chromatography (SFC), capillary electrophoresis (CE) and thin-layer chromatography (TLC). The result of a literature survey done identifies HPLC-based chiral assays as the most dominating technology in use. An overview of various analytical methods engaged for chiral separation and analysis are listed in the table.
Addition of large, nonsensical RNA fragments into many parts of the 16S rRNA unit does not observably alter the function of the ribosomal unit as a whole. Non-coding RNARD7 has the capability to alter processing of rRNA to make the molecules resistant to degradation by carboxylic acid. This is a crucial mechanism in maintaining rRNA concentrations during active growth when acid build-up (due to the substrate phosphorylation required to produce ATP) can become toxic to intracellular functions. Insertion of hammerhead ribozymes that are capable of cis-cleavages along 16S rRNA greatly inhibit function and diminish stability. While most cellular functions degrade heavily after only short period of exposure to hypoxic environments, rRNA remains un-degraded and resolved after six days of prolonged hypoxia. Only after such an extended period of time do rRNA intermediates (indicative of degradation finally occurring) begin to present themselves.
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.
The dry powder is more stable during transport and storage than a solution. It also allows a known amount of material to be reconstituted at a chosen concentration.