This is a working overview of growth hormone secretagogue, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-02 and is reviewed periodically as new material appears.
Activity is mediated mainly through the growth hormone secretagogue receptor, now generally called the ghrelin receptor or GHS-R1a. Binding at this G-protein-coupled receptor triggers phospholipase C signaling, calcium mobilization, and release of growth hormone from pituitary somatotrophs. Reports describe less pronounced stimulation of adrenocorticotropic hormone and prolactin compared with earlier secretagogues such as hexarelin or GHRP-6. Selectivity figures vary between assay systems, so the degree of separation from other secretagogues is an area of ongoing comparison rather than a fixed constant.
In animal and early human studies, ipamorelin produces pulsatile growth hormone release and a secondary rise in insulin-like growth factor 1. The magnitude and duration of that rise depend on route, sampling schedule, and the baseline endocrine state of the subject. Whether repeated exposure alters the response over time is not firmly settled, since some reports describe stable pulsatility while others note attenuation. Most published data come from small samples, which limits the strength of any general claim about long-term behavior.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, a structure that differs from natural ghrelin in length and in the presence of non-natural amino acid residues. Early laboratory work described it as a comparatively selective agent that stimulates growth hormone release with limited effect on other pituitary hormones. The compound is supplied as a lyophilized solid for research use and has no identified natural source in the body.
Quality claims for research peptides vary widely across suppliers. A certificate of analysis should list purity by chromatography, the mass found by spectrometry, and the analytical conditions used. Independent testing at a third-party laboratory is a common way to check identity and purity, because documents alone cannot confirm what is inside a vial. Purity figures describe the proportion of the target peptide among detected species, and they say nothing about biological activity or sterility.
Lyophilized ipamorelin powder is the form usually supplied for laboratory work. Kept dry, protected from light, and held at minus 20 degrees Celsius or below, it remains stable for extended periods, often measured in years. Once dissolved, the peptide degrades faster through hydrolysis, oxidation, and deamidation, so solutions are typically refrigerated and used within weeks. Repeated freeze-thaw cycles and exposure to alkaline conditions accelerate loss of the parent compound.
| Property | Value | Notes |
|---|---|---|
| Peptide class | Synthetic pentapeptide | GHS-R1a agonist family |
| Receptor target | Ghrelin receptor (GHS-R1a) | G-protein-coupled receptor |
| Sequence length | Five amino acid residues | Includes non-natural residues |
| Primary reported output | Pulsatile growth hormone release | Observed in animal and early human work |
| Molecular formula | C38H49N9O5 | Corresponds to roughly 711.9 g/mol |
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.
==== United Kingdom ==== In 2010, unconfirmed reports speculated about the role mephedrone has played in the deaths of several young people in the UK. By July 2010, mephedrone had been alleged to be involved in 52 fatalities in the UK, but detected in only 38 of these cases. Of the nine that coroners had finished investigating, two were caused directly by mephedrone. The first death reported to be caused by mephedrone use was that of 46-year-old John Sterling Smith, who had underlying health problems and repeatedly injected the drug. A report in Forensic Science International in August 2010 stated mephedrone intoxication has been recorded as the cause of death in two cases in Scotland. Post-mortem samples showed the concentration of mephedrone in the blood was 22 mg/L in one case and 3.3 mg/L in the other. The death of a teenager in the UK in November 2009 was widely reported as being caused by mephedrone, but a report by the coroner concluded she had died from natural causes. In March 2010, the deaths of two teenagers in Scunthorpe were widely reported by the media to be caused by mephedrone. Toxicology reports showed the teenagers had not taken any mephedrone and had died as a result of consuming alcohol and methadone, a synthetic opioid. According to Fiona Measham, a criminologist who is a member of the Advisory Council on the Misuse of Drugs, the reporting of the unconfirmed deaths by newspapers followed "the usual cycle of 'exaggeration, distortion, inaccuracy and sensationalism'" associated with the reporting of recreational drug use.
However, it is possible that some isotopes that are now considered stable will be revealed to decay with extremely long half-lives (as happened with bismuth). For each of the 80 stable elements, the number of stable isotopes is given. Only 90 isotopes are stable against any possible decay, and an additional 161 are energetically unstable (see List of nuclides) but have never been observed to decay. Thus, 251 isotopes (nuclides) are stable by definition (including an excited state, tantalum-180m, for which no decay has yet been observed). In April 2019 it was announced that the half-life of xenon-124 had been measured to 1.8 × 1022 years. This is the longest half-life directly measured for any unstable isotope; only the (indirectly measured) half-life of tellurium-128 is longer. Of the chemical elements, only 1 element (tin) has 10 such stable isotopes, 5 have 7 stable isotopes, 7 have 6 stable isotopes, 11 have 5 stable isotopes, 9 have 4 stable isotopes, 5 have 3 stable isotopes, 16 have 2 stable isotopes, and 26 have 1 stable isotope. Additionally, 31 nuclides of the naturally occurring elements have unstable isotopes with a half-life long enough to have survived for the age of the Solar System (108 years or more), and an additional four such nuclides represent three elements (bismuth, thorium, uranium) having no stable isotope. These 35 radioactive naturally occurring nuclides comprise the radioactive primordial nuclides. The total number of primordial nuclides is then 251 (the stable nuclides) plus the 35 radioactive primordial nuclides, for a total of 286.
== The use of "Intracrine" == As described above, intracrine signaling, also called intracrine action, is a process in which a cell produces a hormone that acts within the same cell that synthesized it. However, the term "intracrines" can be used more broadly to refer to all hormones that act on receptors within the cell, regardless of whether they act on their cell of origin. This means that while some intracrines function in a strictly intracrine manner, others may be secreted to influence neighboring cells. In such cases, an intracrine can function in a paracrine manner while still exerting its effects within the original cell through intracellular signaling.
Legendre did an impressive amount of work on elliptic functions, including the classification of elliptic integrals, but it took Abel's study of the inverses of Jacobi's functions to solve the problem completely. He is known for the Legendre transformation, which is used to go from the Lagrangian to the Hamiltonian formulation of classical mechanics. In thermodynamics it is also used to obtain the enthalpy and the Helmholtz and Gibbs (free) energies from the internal energy. He is also the namesake of the Legendre polynomials, solutions to Legendre's differential equation, which occur frequently in physics and engineering applications, such as electrostatics. Legendre is best known as the author of Éléments de géométrie, which was published in 1794 and was the leading elementary text on the topic for around 100 years. This text greatly rearranged and simplified many of the propositions from Euclid's Elements to create a more effective textbook.
Going hitless in 16 at bats during the World Series that fall, in addition to his feud with manager Dick Williams over lack of playing time, resulted in the Athletics fulfilling his trade demand by sending him to the Texas Rangers for Horacio Piña on December 1, 1972. Additionally, the A's wanted to free up the first base position for Gene Tenace who was the star of that same Fall Classic. Opening 1973 batting .188 with one homer and six RBIs, he was dealt along with Rich Hand and Rick Stelmaszek from the Rangers to the California Angels for Jim Spencer and Lloyd Allen on May 20. In 1973, he was seventh in the league in hit by pitches (8). On May 4, 1974, he was released by the Angels. In 907 games over nine seasons, Epstein posted a .244 batting average (695-for-2,854) with 362 runs, 130 home runs, 380 RBIs, 448 bases on balls, .358 on-base percentage and .424 slugging percentage. He finished his career with a .991 fielding percentage playing every inning at first base. In 13 postseason games, he hit only .108 (4-for-37) with two runs scored, one home run, one RBI, and nine walks. In 1991 he was inducted into the Southern California Jewish Sports Hall of Fame. He was inducted as a member of the United States National Jewish Sports Hall of Fame in 2004. Through 2010, he was sixth all-time in career home runs (behind Mike Lieberthal) among Jewish major league baseball players.
Sources: en.wikipedia.org
Three zoos, the Paris Zoological Park (Parc zoologique de Paris, also known as the Zoo de Vincennes), at the Bois de Vincennes in the 12th arrondissement, the Cleres Zoological Park (Parc zoologique de Clères), at a medieval manor in Clères (Seine-Maritime) and the Haute Touche Zoological Park in Obterre (Indre), the largest in France, Three botanical parks, the Arboretum de Chèvreloup in Rocquencourt next to the Château de Versailles, the Jardin botanique exotique de Menton and the Jardin alpin de La Jaÿsinia in Samoëns, Two museums, the Musée de l'abri Pataud in Les Eyzies-de-Tayac and the Harmas de Fabre in Sérignan-du-Comtat, Four scientific sites, the Institut de Paléontologie humaine in Paris, the Centre d'Écologie générale de Brunoy, the Station de Biologie marine et Marinarium de Concarneau and the CRESCO (Centre de Recherche et d'Enseignement sur les Systèmes Côtiers) in Dinard.
=== Microsoft === While at Harvard, Newell visited his brother at Microsoft, which was not yet a major software developer. At the suggestion of the Microsoft executive Steve Ballmer, he dropped out of Harvard and began working at Microsoft. Newell said later that Microsoft was the best place in the world to learn to program at the time. Newell spent 13 years at Microsoft as a programmer and technical executive, and produced the first three releases of the Windows operating system. In late 1995, Doom, a 1993 first-person shooter game developed by id Software, was estimated to be installed on more computers worldwide than Microsoft's new operating system, Windows 95. Newell said: "[id] ... didn't even distribute through retail, it distributed through bulletin boards and other pre-internet mechanisms. To me, that was a lightning bolt. Microsoft was hiring 500-people sales teams and this entire company was 12 people, yet it had created the most widely distributed software in the world. There was a sea change coming." At Microsoft, Newell led development on a port of Doom for Windows 95, which is credited with helping make Windows a viable game platform.
=== The "creation" of life === One ethical question is whether or not it is acceptable to create new life forms, sometimes known as "playing God". Currently, the creation of new life forms not present in nature is at small-scale, the potential benefits and dangers remain unknown, and careful consideration and oversight are ensured for most studies. Many advocates express the great potential value—to agriculture, medicine, and academic knowledge, among other fields—of creating artificial life forms. Creation of new entities could expand scientific knowledge well beyond what is currently known from studying natural phenomena. Yet there is concern that artificial life forms may reduce nature's "purity" (i.e., nature could be somehow corrupted by human intervention and manipulation) and potentially influence the adoption of more engineering-like principles instead of biodiversity- and nature-focused ideals. Some are also concerned that if an artificial life form were to be released into nature, it could hamper biodiversity by beating out natural species for resources (similar to how algal blooms kill marine species). Another concern involves the ethical treatment of newly created entities if they happen to sense pain, sentience, and self-perception. There is an ongoing debate as to whether such life forms should be granted moral or legal rights, though no consensus exists as to how these rights would be administered or enforced.
Frank Furedi (born 1947) is a Hungarian Jewish British Canadian academic known for work on sociology of fear, education, therapy culture, paranoid parenting and sociology of knowledge; in 1970s, was member of International Socialists (IS); later formed the Revolutionary Communist Group, and then broke from that to form Revolutionary Communist Tendency, refounded as the Revolutionary Communist Party in 1978; RCP was distinguished by its contrarianism; among its positions were support for IRA and Saddam Hussein Furedi is now associated with the RCP's successor, the web site Spiked Online. Neil Gaiman fantasy writer Uri Geller (Hebrew: אורי גלר; born 20 December 1946 in British Mandate of Palestine Mandatory Palestine (now Israel), of Hungarian Jewish ancestry, is an Israeli-British illusionist, magician, television personality, self-proclaimed psychic and author of over ten books, both fiction and non-fiction. Ernest Gellner social anthropologist, scholar of nationalism and identity, of Austrian Jewish and Czech Jewish origin. Adele Geras, (née Weston; born 15 March 1944) FRSL is an English writer for young children, teens and adults. She has written more than 95 books for children, young adults, and adults.
Sources: en.wikipedia.org
It is a synthetic pentapeptide in the growth hormone secretagogue family and acts as an agonist at the ghrelin receptor. It is handled as a laboratory research compound rather than a naturally occurring hormone.
Studies generally report growth hormone as the dominant output, with smaller or absent effects on adrenocorticotropic hormone and prolactin. The size of that separation depends on the assay and the dose examined, so it is best described as relative selectivity.
No natural source has been identified, and the molecule is produced by chemical synthesis. Its non-natural residues distinguish it from endogenous ghrelin even though both engage the same receptor.
Keep the powder dry, protected from light, and at minus 20 degrees Celsius or lower. A desiccant and a sealed vial limit moisture uptake. Let the vial reach room temperature before opening to reduce condensation.