If you have been reading about Secretagogue and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-11-12. Numbers and descriptions here follow the published literature rather than marketing material.
Compared with older secretagogues such as hexarelin or GHRP-6, ipamorelin shows weaker stimulation of cortisol, prolactin, and appetite in the animal models used for early characterization. Whether that selectivity is preserved across longer human exposures remains an open question, because published clinical data are limited in size and duration. Reported effects on food intake are generally described as modest. The compound is therefore treated in the literature as a relatively selective research tool rather than a fully characterized therapeutic agent.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Researchers at a pharmaceutical company first described it in the 1990s while screening small peptides for growth hormone releasing activity. Its chain contains five amino acid residues, two of which are non-natural building blocks, including 2-aminoisobutyric acid and a naphthylalanine derivative. The molecule was designed to act at the ghrelin receptor while avoiding several effects observed with earlier secretagogues.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic pentapeptide | Growth hormone secretagogue family |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 | Contains two non-natural residues |
| Molecular formula | C38H49N9O5 | Free base form |
| Molecular weight | 711.85 g/mol | Calculated from formula |
| Primary target | GHS-R1a ghrelin receptor | Agonist activity |
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.
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.
Purity assessment for this peptide relies mainly on reversed-phase high-performance liquid chromatography. A C18 column with a water-acetonitrile gradient containing trifluoroacetic acid separates the target from truncated sequences and oxidation products. Detection near 214 nm exploits the amide backbone, while the aromatic side chains allow additional monitoring close to 280 nm. Reported purity values depend on the method, so a certificate of analysis carries weight only when gradient, column and integration parameters are given.
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.
== Recombinant protein design == The earliest applications of recombinant protein design can be documented in the use of single peptide tags for purification of proteins in affinity chromatography. Since then, a variety of fusion protein design techniques have been developed for applications as diverse as fluorescent protein tags to recombinant fusion protein drugs. Three commonly used design techniques include tandem fusion, domain insertion, and post-translational conjugation.
==== Metal-based nanoparticles ==== Inorganic nanomaterials, (e.g. quantum dots, nanowires, and nanorods) because of their interesting optical and electrical properties, could be used in optoelectronics. Furthermore, the optical and electronic properties of nanomaterials which depend on their size and shape can be tuned via synthetic techniques. There are the possibilities to use those materials in organic material based optoelectronic devices such as organic solar cells, OLEDs etc. The operating principles of such devices are governed by photoinduced processes like electron transfer and energy transfer. The performance of the devices depends on the efficiency of the photoinduced process responsible for their functioning. Therefore, better understanding of those photoinduced processes in organic/inorganic nanomaterial composite systems is necessary in order to use them in optoelectronic devices. Nanoparticles or nanocrystals made of metals, semiconductors, or oxides are of particular interest for their mechanical, electrical, magnetic, optical, chemical and other properties. Nanoparticles have been used as quantum dots and as chemical catalysts such as nanomaterial-based catalysts. Recently, a range of nanoparticles are extensively investigated for biomedical applications including tissue engineering, drug delivery, biosensor. Nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures.
== O == George Andrew Olah (1927–2017), Hungarian and American chemist who worked on the generation and reactivity of carbocations via superacids; 1994 Nobel Prize in Chemistry Marilyn Olmstead (1943–2020), American chemist, expert in small-molecule crystallography Fred Olsen (1891–1986), British-born American chemist, inventor of the ball propellant manufacturing process Lars Onsager (1903–1976), Norwegian and American physical chemist and theoretical physicist who corrected the Debye-Hückel theory of electrolytic solutions, 1968 Nobel Prize in Chemistry Tony Orchard (1941–2005), British inorganic chemist whose research helped to lay the foundations of much modern consumer electronic technology Joan Oró (1923–2004), Spanish (Catalan) biochemist known for studies of the origin of life Hans Christian Ørsted (1777–1851), Danish chemist and physicist who discovered that electric currents create magnetic fields Wilhelm Ostwald (1853–1932), Baltic German physical chemist, 1909 Nobel Prize in Chemistry for contributions to the fields of catalysis, chemical equilibria and reaction velocities Larry E. Overman (born 1943), American organic chemist developing chemical reactions, particularly transition metal catalyzed reactions Geoffrey Ozin (DPhil 1967), British materials chemist known for research on nanomaterials
The muscular layer consists of two layers of muscle, the inner and outer layer. The muscle of the inner layer is arranged in circular rings around the tract, whereas the muscle of the outer layer is arranged longitudinally. The stomach has an extra layer, an inner oblique muscular layer. Between the two muscle layers is the myenteric plexus (Auerbach's plexus). This controls peristalsis. Activity is initiated by the pacemaker cells (interstitial cells of Cajal). The gut has intrinsic peristaltic activity (basal electrical rhythm) due to its self-contained enteric nervous system. The rate can, of course, be modulated by the rest of the autonomic nervous system. The layers are not truly longitudinal or circular, rather the layers of muscle are helical with different pitches. The inner circular is helical with a steep pitch and the outer longitudinal is helical with a much shallower pitch. The coordinated contractions of these layers is called peristalsis and propels the food through the tract. Food in the GI tract is called a bolus (ball of food) from the mouth down to the stomach. After the stomach, the food is partially digested and semi-liquid, and is referred to as chyme. In the large intestine the remaining semi-solid substance is referred to as faeces. The circular muscle layer prevents food from travelling backward and the longitudinal layer shortens the tract. The thickness of the muscular layer varies in each part of the tract:
Sources: en.wikipedia.org
Weizmann's political efforts picked up speed, and on 10 December 1914 he met with Herbert Samuel, a British Cabinet member and a secular Jew who had studied Zionism; Samuel believed Weizmann's demands were too modest. Two days later, Weizmann met Balfour again, for the first time since their initial meeting in 1905; Balfour had been out of government ever since his electoral defeat in 1906, but remained a senior member of the Conservative Party in their role as Official Opposition. A month later, Samuel circulated a memorandum entitled The Future of Palestine to his Cabinet colleagues. The memorandum stated: "I am assured that the solution of the problem of Palestine which would be much the most welcome to the leaders and supporters of the Zionist movement throughout the world would be the annexation of the country to the British Empire". Samuel discussed a copy of his memorandum with Nathan Rothschild in February 1915, a month before the latter's death. It was the first time in an official record that enlisting the support of Jews as a war measure had been proposed. Many further discussions followed, including the initial meetings in 1915–16 between Lloyd George, who had been appointed Minister of Munitions in May 1915, and Weizmann, who was appointed as a scientific advisor to the ministry in September 1915. Seventeen years later, in his War Memoirs, Lloyd George described these meetings as being the "fount and origin" of the declaration; historians have rejected this claim.
Sulfur forms several polyatomic molecules. The best-known allotrope is octasulfur, cyclo-S8. The point group of cyclo-S8 is D4d and its dipole moment is 0 D. Octasulfur is a soft, bright-yellow solid that is odorless. It melts at 115.21 °C (239.38 °F), and boils at 444.6 °C (832.3 °F). At 95.2 °C (203.4 °F), below its melting temperature, cyclo-octasulfur begins slowly changing from α-octasulfur to the β-polymorph. The structure of the S8 ring is virtually unchanged by this phase transition, which affects the intermolecular interactions. Cooling molten sulfur freezes at 119.6 °C (247.3 °F), as it predominantly consists of the β-S8 molecules. Between its melting and boiling temperatures, octasulfur changes its allotrope again, turning from β-octasulfur to γ-sulfur, again accompanied by a lower density but increased viscosity due to the formation of polymers. At higher temperatures, the viscosity decreases as depolymerization occurs. Molten sulfur assumes a dark red color above 200 °C (392 °F). The density of sulfur is about 2 g/cm3, depending on the allotrope; all of the stable allotropes are excellent electrical insulators. The sublimation of sulfur becomes noticeable more or less between 20 °C (68 °F) and 50 °C (122 °F), and occurs readily in boiling water at 100 °C (212 °F). Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene. Sulfur is also soluble in supercritical carbon dioxide.
=== Geometry === The majority of β-strands are arranged adjacent to other strands and form an extensive hydrogen bond network with their neighbors in which the N−H groups in the backbone of one strand establish hydrogen bonds with the C=O groups in the backbone of the adjacent strands. In the fully extended β-strand, successive side chains point straight up and straight down in an alternating pattern. Adjacent β-strands in a β-sheet are aligned so that their Cα atoms are adjacent and their side chains point in the same direction. The "pleated" appearance of β-strands arises from tetrahedral chemical bonding at the Cα atom; for example, if a side chain points straight up, then the bonds to the C′ must point slightly downwards, since its bond angle is approximately 109.5°. The pleating causes the distance between Cαi and Cαi + 2 to be approximately 6 Å (0.60 nm), rather than the 7.6 Å (0.76 nm) expected from two fully extended trans peptides. The "sideways" distance between adjacent Cα atoms in hydrogen-bonded β-strands is roughly 5 Å (0.50 nm).
Sources: en.wikipedia.org
Chain of Gold is a young adult-urban fantasy-novel by Cassandra Clare. It is the first book in The Last Hours, which is chronologically second in The Shadowhunter Chronicles. The book follows the events that occur in the London area in 1903, focusing on the residents of the London Institute. The chapter titles, like in The Infernal Devices, are all taken from poetry of the Victorian and Edwardian era that the characters would be familiar with, and the book title was taken from the Charles Dickens novel Great Expectations.
The pentastack is a hazardous five-drug mixture discussed in online looksmaxxing communities that combines powerful stimulants and severe central nervous system depressants. It consists of: Adderall, dextromethorphan, pregabalin, ketamine and BDO (1,4-Butanediol). It has been compared to the date rape drug Rohypnol by Vanity Fair.
In January 2021, The government of Kenya unanimously passed the anti-doping bill into law that will enable the country to comply with the World 2021 anti-doping code. In April 2021, The US Senate passes the "United States Anti-Doping Agency Reauthorization Act of 2021" to reauthorize the United States Doping Agency.
During the process of DNA replication, errors occasionally occur in the polymerization of the second strand. These errors, called mutations, can affect the phenotype of an organism, especially if they occur within the protein coding sequence of a gene. Error rates are usually very low—1 error in every 10–100 million bases—due to the "proofreading" ability of DNA polymerases. Processes that increase the rate of changes in DNA are called mutagenic: mutagenic chemicals promote errors in DNA replication, often by interfering with the structure of base-pairing, while UV radiation induces mutations by causing damage to the DNA structure. Chemical damage to DNA occurs naturally as well and cells use DNA repair mechanisms to repair mismatches and breaks. The repair does not, however, always restore the original sequence. A particularly important source of DNA damages appears to be reactive oxygen species produced by cellular aerobic respiration, and these can lead to mutations.
Sources: en.wikipedia.org
It is a synthetic pentapeptide in the growth hormone secretagogue family. The chain contains five residues, two of which are non-natural amino acids.
It acts as an agonist at the growth hormone secretagogue receptor, also known as the ghrelin receptor. Binding at pituitary somatotroph cells promotes growth hormone release.
Early studies report weaker effects on cortisol, prolactin, and appetite than compounds such as GHRP-6. The size of that difference in humans is not firmly established.
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.