The short version of cyclic heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-10 and is reviewed periodically as new material appears.
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 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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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 class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
== Mosaic Diagnostics, formerly Great Plains Laboratory == William Shaw's laboratory is known for performing nonstandard tests which have been used by alternative medicine practitioners to support discredited diagnoses. Great Plains Laboratory's urine mycotoxin test is not validated nor recommended for diagnosing any condition. In May 2020, early in the COVID-19 pandemic, Great Plains marketed unproven antibody tests.
== Analogs == Growth-hormone-releasing hormone is the lead compound for a number of structural and functional analogs, such as Pro-Pro-hGHRH(1-44)-Gly-Gly-Cys, CJC-1293, and CJC-1295. Many GHRH analogs remain primarily research chemicals, although some have specific applications. Sermorelin, a functional peptide fragment of GHRH, has been used in the diagnosis of deficiencies in growth hormone secretion. Tesamorelin, under the trade name Egrifta, received U.S. Food and Drug Administration approval in 2010 for the treatment of lipodystrophy in HIV patients under highly active antiretroviral therapy, and, in 2011, was investigated for effects on certain cognitive tests in the elderly. As a category, the use of GHRH analogs by professional athletes may be prohibited by restrictions on doping in sport because they act as growth hormone secretagogues.
Two policemen disguised as orienteers, Bertil Brosved and Ulf Högenberg, tried to arrest him at the same time as Olofsson pulled a pistol out of his waistband and fired two shots. Högenberg was hit in the shoulder. Olofsson was first sentenced to ten years in prison, but the Court of Appeal changed the sentence to eight years. Norgren was sentenced to 12 years, which was the most severe punishment a Swedish court could impose at that time. On 4 February 1969, Olofsson escaped from Kumla Prison and fled to the Canary Islands. He then entered West Germany on a fake passport, flying to Frankfurt am Main, where he lived until he was arrested by the German police. He was escorted to the ferry in Travemünde where two Swedish police officers met him. He was then taken via Malmö back to the Kumla Prison. Two months before he was to be released, he escaped again, from Lingatan Prison, an open institution in Bohuslän. On 2 February 1973, he was arrested in the dining room of the Kurhotel in Ulricehamn. Police had received a tip from a cleaning lady who had seen a gun in his hotel room. At the time of his arrest, he had been on the run for seven months and had robbed a bank in Gothenburg. In May 1973, he was sentenced to six years in prison and transported to the Kalmar Prison.
=== Alkenes === Alkenes often produce stronger molecular ion peaks than alkanes due to the lower ionization energy of a pi electron than a σ electron. After the ionization, double bonds can migrate easily, resulting in almost impossible determination of isomers. Allylic cleavage is most significant fragmentation mode due to resonance stabilization.
Sources: en.wikipedia.org
=== Improved mine safety === An ultrasonic bolt elongation monitor developed by a NASA scientist for testing tension and high-pressure loads on bolts and fasteners has continued to evolve over the past three decades. Today, the same scientist and Luna Innovations are using a digital adaptation of this same device for non-destructive evaluation (NDE) of railroad ties, groundwater analysis, radiation, and as a medical testing device to assess levels of internal swelling and pressure for patients with intracranial pressure and compartment syndrome, a painful condition that results when pressure within muscles builds to dangerous levels.
Div. 1: Single early – with cup-shaped single flowers, no larger than 8 cm (3 inches) across. They bloom early to mid-season. Growing 15 to 45 cm (6 to 18 inches) tall. Div. 2: Double early – with fully double flowers, bowl shaped to 8 cm (3 inches) across. Plants typically grow from 30–40 cm (12–16 inches) tall. Div. 3: Triumph – single, cup shaped flowers up to 6 cm (2.5 inches) wide. Plants grow 35–60 cm (14–24 inches) tall and bloom mid to late season. Div. 4: Darwin hybrid – single flowers are ovoid in shape and up to 6 cm (2.5 inches) wide. Plants grow 50–70 cm (20–28 inches) tall and bloom mid to late season. This group should not be confused with older Darwin tulips, which belong in the Single Late Group below. Div. 5: Single late – cup or goblet-shaped flowers up to 8 cm (3 inches) wide, some plants produce multi-flowering stems. Plants grow 45–75 cm (18–30 inches) tall and bloom late season. Div. 6: Lily-flowered – the flowers possess a distinct narrow 'waist' with pointed and reflexed petals. Previously included with the old Darwins, only became a group in their own right in 1958. Div. 7: Fringed (Crispa) – cup or goblet-shaped blossoms edged with spiked or crystal-like fringes, sometimes called "tulips for touch" because of the temptation to "test" the fringes to see if they are real or made of glass. Perennials with a tendency to naturalise in woodland areas, growing 45–65 cm (18–26 inches) tall and blooming in late season. Div. 8: Viridiflora Div. 9: Rembrandt Div. 10: Parrot Div. 11: Double late – Large, heavy blooms.
In May 2007, Unilever became the first company to commit to sourcing all tea in a sustainable manner. Working with the Rainforest Alliance, an international environmental NGO, Unilever, announced all Lipton Yellow Label tea bags sold in Western Europe would be certified by 2010 and all Lipton tea bags sold globally by 2015. Lipton's own tea estates were among the first to be certified. Lipton tea bearing the Rainforest Alliance seal appeared on Western European markets in 2008 and started appearing in North America in 2009. On 6 May 2009, Lipton received a Corporate Green Globe Award for its work with the Rainforest Alliance. In 2011, PETA criticized Unilever for conducting and funding experiments on rabbits, pigs and other animals in an attempt to make human health claims about the tea's ingredients. According to the animal rights organization, Unilever decided to end the practice after receiving more than 40,000 appeals from PETA supporters and days before PETA made plans to launch its "Lipton CruelTEA" campaign. Unilever no longer tests their products on animals unless required to by governments as part of their regulatory requirements. Unilever reached an agreement in November 2021 to sell the majority of its tea business to private equity firm CVC Capital Partners for €4.5 billion. This included the Lipton brand except where Unilever retained its use for tea in India, Nepal, and Indonesia, for ready to drink teas globally, and for soup mixes in North America. The sale was completed in July 2022, with the new company named ‘Lipton Teas and Infusions’.
After Best died in 1978 and complete documentation (including Banting's papers and Macleod's account of events) became available through the Thomas Fisher Rare Book Library, historian Michael Bliss compiled a comprehensive account of the events surrounding the discovery of insulin. Notably, Bliss's account reviews the nominations and Nobel Prize committee's own investigations that culminated in the 1923 decision.
== S == safe sex – safer sex – salmonella – salvage therapy – SAMHSA – sarcoma – seborrheic dermatitis – secondary prophylaxis – sepsis – seroconversion – serologic test – seroprevalence – serosorting – serostatus – serum – serum glutamic oxaloacetic transaminase (SGOT) – serum glutamic pyruvate transaminase (SGPT) – sexually transmitted disease (STD) – shingles – SHIV – side effects – simian immunodeficiency virus (SIV) – sinusitis – social integration SIT – SIV – Special Projects of National Significance (SPNS) – spinal tap – spleen – splenomegaly – sputum analysis – standard of care – staphylococcus – STD – stem cells (FDCs) – steroid – Stevens–Johnson syndrome – STI – stomatitis – strain – stratification – structured intermittent therapy (SIT) – structured treatment interruption (STI) – study endpoint – subarachnoid space – subclinical infection – subcutaneous (SQ) – Substance Abuse and Mental Health Services Administration (SAMHSA) – subunit HIV vaccine – sulfa drug – sulfonamides – superantigen – suppressor T cell – surrogate marker – surveillance – susceptible – symptoms – syncytium – syndrome – synergy – synergistic – synthesis – syphilis – systemic
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
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.