This is a working overview of selectivity, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-10 and is reviewed periodically as new material appears.
Ipamorelin is a synthetic pentapeptide classified as a growth hormone secretagogue. Its sequence, Aib-His-D-2-Nal-D-Phe-Lys-NH2, combines three non-proteinogenic residues with a C-terminal amide. The N-terminal aminoisobutyric acid unit and the two aromatic D-amino acids distinguish it from peptides assembled only from standard L-amino acids. Its formula is C38H49N9O5, corresponding to an average mass near 711.9 Da. At neutral pH the molecule carries a net positive charge, a property that shapes its behaviour in chromatographic and electrophoretic systems.
The compound was developed at Novo Nordisk during the 1990s as part of a programme seeking secretagogues with improved selectivity. It was described in the peer-reviewed literature in 1998 alongside related pentapeptides from the same series. Investigators advanced it because it raised growth hormone output in animal models while leaving other pituitary hormones comparatively unaffected. The development code NNC 26-0161 appears in earlier reports, and ipamorelin later became the common designation in published work.
Selectivity is the property most often attached to this peptide. Published animal and early human studies record increases in growth hormone release after administration, with adrenocorticotropic hormone and cortisol responses remaining small by comparison. Effects on appetite-related pathways also appear weaker than those reported for several earlier secretagogues. Reviews that compare members of the growth hormone secretagogue family cite these findings frequently, though the receptor-level explanation for the selectivity continues to be debated rather than settled.
Material supplied for research use is normally a white to off-white lyophilized powder. The solid is hygroscopic and is handled in a low-humidity environment to limit water uptake. Bulk quantities are frequently shipped in sealed vials under inert gas. Once reconstituted in water or a neutral buffer, the solution is less stable than the dry powder and is usually divided into single-use aliquots.
Long-term storage of the dry powder is typically at minus twenty degrees Celsius or lower, protected from light and moisture. Solutions are commonly kept frozen and thawed only once, because repeated freeze-thaw cycles can promote aggregation and loss of measurable peptide content. Buffers near neutral pH are preferred over strongly acidic or strongly basic conditions. Shipping at ambient temperature is acceptable for short periods when the powder remains sealed and desiccated.
Identity and purity are assessed by complementary methods rather than a single test. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and reports a percentage purity. Mass spectrometry, most often with electrospray ionization, confirms the expected molecular mass and detects sequence-related variants. Amino acid analysis can verify composition, while water content and residual counterion measurements support the mass balance of a batch. Stability studies under accelerated conditions are used to estimate shelf life, though such estimates carry uncertainty for long-term storage.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H49N9O5 | Pentapeptide with C-terminal amide |
| Average mass | Approximately 711.9 Da | Value derived from the formula |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and aqueous acetonitrile | Dissolution aided by acidic diluents |
| Common synonyms | Ipamorelin; NNC 26-0161 | Code name used in early reports |
Mass spectrometry confirms identity and reveals structural deviations that chromatography alone can miss. Positive-mode electrospray ionisation generally yields multiply charged ions whose deconvoluted mass is checked against the theoretical value. Amino acid analysis, and enzymatic digestion with subsequent fragment mapping, provide independent confirmation of sequence and of the terminal amide. Analysts take care to separate the target from deletion sequences, which may differ by one residue and therefore by only a small mass increment.
The lyophilised solid is normally held at -20 °C or colder, shielded from light and moisture. Stability in that state is measured in years, although shelf life depends on residual water content and the container seal. Once dissolved, the peptide is more fragile: aqueous solutions are commonly kept at 2-8 °C and used within days to weeks, and repeated freeze-thaw cycling is avoided. Strongly acidic or basic conditions accelerate hydrolysis, and prolonged exposure to them can strip the terminal amide.
Ipamorelin is a synthetic pentapeptide first described in the 1990s by researchers at Novo Nordisk during a program to develop selective growth hormone secretagogues. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, incorporating two non-natural residues, alpha-aminoisobutyric acid and D-2-naphthylalanine. The C-terminus is amidated, and the material is supplied as a white lyophilized powder. The molecular formula is C38H49N9O5 and the monoisotopic mass is approximately 711.85 daltons. The short chain and modified residues give it greater resistance to enzymatic degradation than many larger peptide hormones.
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor type 1a, the same G protein-coupled receptor that binds ghrelin. Receptor activation couples to Gq/11 signaling, raising intracellular calcium through inositol trisphosphate and diacylglycerol, which in turn promotes exocytosis of growth hormone from pituitary somatotroph cells. Ipamorelin binds this receptor with high affinity and shows weak activity at other secretagogue-related targets in vitro. Its action requires the intact receptor and is not reversed by growth hormone-releasing hormone antagonists.
Compared with earlier growth hormone secretagogues such as GHRP-6 and hexarelin, ipamorelin has been reported to produce less stimulation of adrenocorticotropic hormone, cortisol, and prolactin in animal and early human studies. This selectivity is usually attributed to differences in receptor subtype interactions and to the tissue distribution of the receptor. Effects on appetite appear weaker than those of ghrelin itself, although the supporting evidence base is small. Whether these differences produce a distinct clinical profile remains an open question, since controlled human trials are limited.
Belize has a rich variety of wildlife because of its position between North and South America and a wide range of climates and habitats for plant and animal life. Belize's low human population and approximately 22,970 square kilometres (8,867 sq mi) of undistributed land make for an ideal home for the more than 5,000 species of plants and hundreds of species of animals, including armadillos, snakes, and monkeys. The Cockscomb Basin Wildlife Sanctuary is a nature reserve in south-central Belize established to protect the forests, fauna, and watersheds of an approximately 400 km2 (150 sq mi) area of the eastern slopes of the Maya Mountains. The reserve was founded in 1986 as the first wilderness sanctuary for the jaguar and is regarded by one author as the premier site for jaguar preservation in the world.
=== CTS and activity === Work-related factors that increase risk of CTS include vibration (5.4 odds ratio), hand force (4.2), and repetition (2.3). Exposure to wrist extension or flexion at work increases the risk of CTS by 2.0 times. As of 2023, a systematic review of studies looking at the relationship between CTS and computer use has found current studies to be inconclusive and contradictory, due to poor study methods and confounding variables not being accounted for. The international debate regarding the relationship between CTS and repetitive hand use (at work in particular) is ongoing. The Occupational Safety and Health Administration (OSHA) has adopted rules and regulations regarding so-called "cumulative trauma disorders" based concerns regarding potential harm from exposure to repetitive tasks, force, posture, and vibration. A review of available scientific data by the National Institute for Occupational Safety and Health (NIOSH) indicated that job tasks that involve highly repetitive manual acts or specific wrist postures were associated with symptoms of CTS. There was no clear distinction between paresthesia (appropriate) from pain (inappropriate), and causation was not established. The distinction from work-related arm pains that are not carpal tunnel syndrome was unclear. It is proposed that repetitive use of the arm can affect the biomechanics of the upper limb or cause damage to tissues.
=== Semiconductors === Semiconductor intellectual property, a business model for licensing intellectual property Single in-line package, for packaging electronic components System in package, chip technology, also known as a chip stack multi-chip module Silicon photonics, silicon semiconductor used as an optical medium
Sources: en.wikipedia.org
As alternatives to pre-university education, however, courses are offered in other post-secondary education institutions, including at polytechnics and Institute of Technical Education (ITE) colleges. Singapore has six public universities, of which the National University of Singapore (NUS) and Nanyang Technological University (NTU) are among the top 20 universities in the world. National examinations are standardised across all schools, with a test taken after each stage. After the first six years of education, students take the Primary School Leaving Examination (PSLE), which determines their placement at secondary school. At the end of the secondary stage, GCE O-Level or GCE N-Level exams are taken; at the end of the following pre-university stage, the GCE A-Level exams are taken. Some schools have a degree of freedom in their curriculum and are known as autonomous schools, for secondary education level and above. Singapore is also an education hub, with more than 80,000 international students in 2006. 5,000 Malaysian students cross the Johor–Singapore Causeway daily to attend schools in Singapore. In 2009, 20% of all students in Singaporean universities were international students—the maximum cap allowed, a majority from ASEAN, China and India. Singapore students have excelled in many of the world education benchmarks in maths, science and reading. In 2015, both its primary and secondary students rank first in OECD's global school performance rankings across 76 countries—described as the most comprehensive map of education standards.
==== Fatal outcomes in case reports ==== A 2017 case report details the severe, prolonged episode of drug-induced parkinsonism in a 68‑year‑old man in the United States that ultimately led to his death roughly five months after receiving two injections of paliperidone palmitate (234 mg followed one week later by 156 mg). The authors state that "practitioners should be cognizant of the potential long‑term consequences of paliperidone LAI." A 47‑year‑old man (Japan, 2017) developed acute and persistent circulatory failure after receiving paliperidone palmitate injections. Despite surgical removal of the hip tissue suspected of containing the paliperidone palmitate depot, he died of multiple organ failure. When examining the removed tissue, it seemed that paliperidone palmitate was not present, and Janssen, the drug manufacturer, does not recommend this approach since it is practically impossible to locate the depot of paliperidone. The optimal treatment of long‐acting injectable (LAI) antipsychotic poisonings is unknown. In 2019, it was reported that a 33-year-old man in France was found dead in his room at his parents' home after receiving a single 819 mg injection of Trevicta (paliperidone palmitate three‑monthly formulation). Toxicological analysis of femoral blood revealed paliperidone at 240 μg/L; no other substance was detected. The authors concluded that paliperidone poisoning was the highly likely cause of death.
==== Development of oral antivirals ==== In November 2021, Pfizer launched a new COVID-19 oral antivirus treatment known as Paxlovid. In January 2022, the Pfizer CEO Albert Bourla confirmed that the trial results of a fourth dose were pending until March 2022. He said that the firm was setting up a collaboration to develop an anti-COVID pill treatment along with a French company, Novasep. He also said the COVID vaccine was "safe and efficient" for children. In May 2022, reports emerged of patients experiencing "rebound" symptoms after completing a five-day course of Paxlovid. The FDA responded by announcing they had performed additional analyses of the drug's clinical trial data, and decided against changing its recommendations. U.S. President Joe Biden and Dr. Anthony Fauci were both reported to experience this rebound syndrome in the months that followed, while continuing to recommend the drug for those who may benefit from it.
=== Regulatory approval === Lurasidone was approved in the United States for the treatment of schizophrenia in October 2010 and for the treatment of depressive episodes associated with bipolar I disorder in June 2013. In 2015, lurasidone was studied for major depressive disorder with mixed features in a randomized trial and had a positive result, however it did not receive an FDA indication for it. In 2017, the FDA approved lurasidone for schizophrenia in adolescents age 13-17. In 2018, lurasidone was approved for bipolar depression in children and adolescents age 10-17. It received regulatory approval in the United Kingdom in September 2014. In October 2014, NHS Scotland advised use of lurasidone for schizophrenic adults who have not seen improvements with previous antipsychotics due to problems that arise from weight gain or changes in metabolic pathways when taking other medications. The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) issued a positive opinion for it in January 2014, and it was approved for medical use by the EMA in March 2014. It was launched in Canada for the treatment of schizophrenia in September 2012, Health Canada giving their Summary Basis of Decision (SBD) as favourable on 15 October 2012. The European Commission has granted a marketing authorization for once-daily oral lurasidone for the treatment of schizophrenia in adults. It is approved for use in the EU. Generic versions of lurasidone were approved for use in the United States in January 2019 and became available in 2023.
Sources: en.wikipedia.org
In the Crimean war (1853–1856), mustard poultices were used for chest and abdominal complaints, including dysentery and cholera. During the American Civil War (1861–1865), poultices were applied to wounds when antiseptics such as iodine were unavailable. Honey-based poultices were used to aid wound healing during the world wars, taking advantage of honey's antimicrobial properties. Decline and survival in traditional medicine
=== The 1990s === Douglas Hart had moonlighted with the Acid Angels in 1988, and left the band in 1991, to have a career in film making, before picking up his bass again in 2006, playing with the Sian Alice Group, Le Volume Courbe, and Cristine. Thomas also quit the band to join Renegade Soundwave. The fluid nature of the Mary Chain's line up continued throughout their entire career, with a revolving door of drummers, bassists and guitarists being recruited for TV appearances and gigs whenever they were required, the only constants being the Reid brothers. The Reid brothers recruited former Starlings rhythm section Matthew Parkin and Barry Blackler to replace Hart and Thomas. The brothers bought their own recording studio in 1991 in Elephant & Castle in South London, which they dubbed The Drugstore, and they returned in February 1992 with the first fruits of the new studio, their next single, "Reverence", which gave them their biggest hit single in almost five years, reaching No. 10 in the UK. Spitting feedback and punk rock bile in every direction, the track was banned from being played on BBC Radio 1 and from Top of the Pops, due to its potentially offensive lyrics ('I wanna die just like JFK, I wanna die in the USA'...'I wanna die just like Jesus Christ, I wanna die on a bed of spikes'). The single was followed by the release of the album Honey's Dead (1992), which received mixed reviews.
== Etymology == The English word "tofu" comes from Japanese tōfu (豆腐, see below), which in turn borrows Chinese 豆腐 (Mandarin: dòufǔ or tòufu) 'bean ferment'. The earliest documentation of the word in English is in the 1704 translation of Domingo Fernández Navarrete's A Collection of Voyages and Travels, that describes how tofu was made. The word towfu also appears in a 1770 letter from the English merchant James Flint to Benjamin Franklin. The term "bean curd(s)" for tofu has been used in the United States since at least 1840.
Sources: en.wikipedia.org
It is a synthetic five-amino-acid peptide that acts as a growth hormone secretagogue. Three of its residues are non-standard amino acids, and the chain ends in an amide rather than a free acid. The molecule is small enough that it can be characterised by routine peptide analytical techniques.
It has not received marketing approval as a medicine in the United States or the European Union. Supplied material is generally described and handled as a research chemical. Regulatory treatment varies by jurisdiction, and some countries restrict growth hormone secretagogues under sports or medicines legislation.
Earlier secretagogues were associated with broader hormonal responses, including measurable changes in cortisol and prolactin. Reports on this peptide describe a narrower profile in which growth hormone release is the most prominent effect. The observation is influential because it shapes how the compound is compared with other members of the same receptor family.
Dry powder is held at minus twenty degrees Celsius or colder, away from light and moisture. Sealed vials under inert gas limit degradation during storage.