If you have been reading about GHS-R1a 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 2026-07-07. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Ipamorelin is a synthetic pentapeptide that acts on the growth hormone secretagogue receptor, also known as the ghrelin receptor. Its sequence contains five amino acid residues, including a non-natural residue that increases stability against enzymatic breakdown. The compound was developed in the 1990s as part of research into small peptides that stimulate pituitary hormone release. Unlike larger protein hormones, it can be produced by solid-phase peptide synthesis and characterized by standard analytical methods.
At the receptor level, ipamorelin binds GHS-R1a and triggers signaling through Gq-coupled pathways. Activation leads to calcium release and downstream effects in pituitary somatotroph cells. These events promote the release of growth hormone into circulation. The response depends on the presence of the receptor and on the physiological state of the animal or tissue studied. Because the receptor is also found in other tissues, effects beyond the pituitary have been examined in laboratory models, though the extent of those effects remains an area of ongoing study.
| 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 |
Ipamorelin 是一种合成五肽，序列为 Aib-His-D-2-Nal-D-Phe-Lys-NH2，分子式 C38H49N9O5，游离碱分子量约 711.85 g/mol。它属于生长激素促分泌素（GHS）家族，作用靶点是胃饥饿素受体 GHS-R1a。该化合物由诺和诺德的研究团队在二十世纪九十年代末报道，设计目标是提高对生长激素释放的选择性。C 端酰胺化与 N 端 Aib 残基是两个用于抵抗肽酶降解的结构特征。
在 GHS 家族中，早期肽类如 GHRP-6 与 GHRP-2 会同时促进生长激素、皮质醇与催乳素的释放，并明显增加食欲。Ipamorelin 在动物与早期人体研究中表现出对生长激素释放的相对选择性，对上述其他激素的影响较小。这种差异通常归因于受体结合模式与下游信号偏向的不同，而完整的分子解释仍有待补充。需要区分的是，选择性是研究观察中的相对程度，并非绝对界限。
从用途定位看，ipamorelin 目前主要以研究用肽的身份被讨论，未见主要药品监管机构将其批准为治疗药物。市售材料通常标注仅供研究使用，不得用于人体或诊断程序。文献中它常与生长激素促分泌素、GHS-R1a 激动剂、胃饥饿素拟似物等表述并列出现。既有研究的样本量普遍偏小，因此对其效应强度与一致性的描述应保持谨慎。
Selectivity distinguishes ipamorelin from first-generation secretagogues such as GHRP-6. At doses that reliably raise growth hormone, it shows little stimulation of adrenocorticotropic hormone or cortisol release in animal models, and it does not markedly raise prolactin or appetite. Binding at GHS-R1a on pituitary somatotrophs triggers calcium influx and pulsatile growth hormone secretion. Because the compound mimics the natural ghrelin signal, the release pattern tends to follow the body's own rhythm rather than producing a sustained elevation.
Most published work on ipamorelin comes from rodent studies and small early-phase human trials. Subcutaneous and intravenous routes have been used, while oral delivery is limited by poor absorption and rapid breakdown in the gut. The reported plasma half-life is short, on the order of two hours, and varies with species and assay method. Whether chronic use produces meaningful clinical benefit remains unresolved, and long-term safety data in humans are sparse. No major regulatory agency has approved the compound as a therapeutic drug.
Human data remain limited and come mainly from small, short-term studies conducted decades ago. The peptide has not received approval as a medicine from major regulators, so current availability is largely as a research chemical. Reported effects on growth hormone pulsatility, appetite, and body composition should be read as preliminary, since few independent groups have replicated the original findings. Analytical characterization of research-grade material varies between suppliers, which complicates comparison across studies. Regulatory status also differs by country, and some jurisdictions classify it as a prescription-only or otherwise restricted item.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class. It acts as an agonist at the ghrelin receptor, also called the growth hormone secretagogue receptor type 1a. The compound was designed in the 1990s during a search for agents that release growth hormone with fewer off-target hormonal effects than earlier secretagogues. It appears in the research literature under several sequence-based names. Material supplied for laboratory work is normally a lyophilized solid, and it is not marketed as an approved therapeutic in major jurisdictions.
The molecule contains five residues, including alpha-aminoisobutyric acid, D-2-naphthylalanine, and D-phenylalanine, and it ends in a lysine amide. Non-natural and D-configured residues make the chain less susceptible to common peptidases, which helps explain its resistance to rapid breakdown. Its molecular formula is C38H49N9O5, corresponding to a free-base mass near 711.9 daltons. The C-terminal amide removes a negative charge and is a recurring feature in receptor-active peptides of this family. These structural choices are usually discussed as the basis for its selectivity profile.
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.
== Ex vivo or in vivo methods == Methods that screen protein–protein interactions in the living cells. Bimolecular fluorescence complementation (BiFC) is a technique for observing the interactions of proteins. Combining it with other new techniques, dual expression recombinase based (DERB) methods can enable the screening of protein–protein interactions and their modulators. The yeast two-hybrid screen investigates the interaction between artificial fusion proteins inside the nucleus of yeast. This approach can identify the binding partners of a protein without bias. However, the method has a notoriously high false-positive rate, which makes it necessary to verify the identified interactions by co-immunoprecipitation.
Axial oscillations of ion rings are detected by their image current induced on the outer electrode which is split into two symmetrical pick-up sensors connected to a differential amplifier. By processing data in a manner similar to that used in Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS), the trap can be used as a mass analyzer. Like in FTICR-MS, all the ions are detected simultaneously over some given period of time and resolution can be improved by increasing the strength of the field or by increasing the detection period. The Orbitrap differs from FTICR-MS by the absence of a magnetic field and hence has a significantly slower decrease of resolving power with increasing m/z.
12 September Your Flight in Their Hands, about aviation safety in Europe; over a million passenger flights occurred in the UK each year in the early 1990s, but no crash due to ATC error has taken place; flights were expected to double in 20 years; the technology being deployed in UK airspace, with Gordon Doggett, head of the London Area Control Centre (LATCC); Keith Mack, the Director-General from 1988 to 1993 of Eurocontrol; a British Airways Boeing 737 BA466 takes a route over Ortac to Madrid; Karl-Heinz Neumeister, the Secretary-General of the Association of European Airlines; the aviation writer Rigas Doganis. Directed by Richard Vaughan, produced by Chris Haws, made by InCA Productions 19 September Fear of Falling, about rock climbing and caving equipment; the single-rope technique (SRT), demonstrated by Nigel Atkins of Pennine National Caving, with a dynamic climbing rope, maillon rapide, snap-gate carabiner, ascender and descender; Ben Lyon of Tebay; a climbing harness, designed by Don Whillans, and the belay loop at Troll Safety Equipment (later Bacou-Dalloz, bought by Sperian of France) in Saddleworth; Simon Nadin; the Foundry indoor climbing centre, opened by Jerry Moffatt in 1991; Undercover Rock at St Werburgh's Church, Bristol; sport climbing; Ben Moon in Derbyshire. Directed by Steve Stevenson, produced by Mike Wallington, made by Parvenu Productions 3 October Family Fortunes, about how children's mental development or health is affected or hindered by growing up in a one-parent-family.
Sources: en.wikipedia.org
Open-angle glaucoma usually presents with no symptoms early in the course of the disease, but it may gradually progress to involve difficulties with vision. It usually involves deficits in the peripheral vision followed by central vision loss as the disease progresses, but less commonly it may present as central vision loss or patchy areas of vision loss. On an eye examination, optic nerve changes are seen indicating damage to the optic nerve head (increased cup-to-disc ratio on fundoscopic examination). Acute angle-closure glaucoma, a medical emergency due to the risk of impending permanent vision loss, is characterized by sudden ocular pain, seeing halos around lights, red eye, very high intraocular pressure, nausea and vomiting, and suddenly decreased vision. Acute angle-closure glaucoma may further present with corneal edema, engorged conjunctival vessels, and a fixed and dilated pupil on examination. Opaque specks may occur in the lens in glaucoma, known as glaukomflecken. The word is German, meaning "glaucoma-specks".
== Histopathology == Although the exact cause of this condition is not known, it is an inflammatory disorder characterized by collagen degeneration, combined with a granulomatous response. It always involves the dermis diffusely, and sometimes also involves the deeper fat layer. Commonly, dermal blood vessels are thickened (Microangiopathy). It can be precipitated by local trauma, though it often occurs without any injury. As a metabolically driven skin disorder, the pathology is characterized by poor intracellular glucose utilization leading to metabolically stressed fibroblasts. Despite an increased GLUT-1 response, fibroblasts in NL fail to produce normal collagen, weakening and breaking down the skin's structure. Vascular impairments reduce oxygen and nutrient circulation, creating hypoxia and tissue breakdown.
== Isotopes == Twelve radioisotopes of nobelium have been characterized, with the most stable being 259No with a half-life of 58 minutes. Longer half-lives are expected for the as-yet-unknown 261No and 263No. An isomeric level has been found in 253No and K-isomers have been found in 250No, 252No and 254No to date.
Sources: en.wikipedia.org
=== Sponsor === Throughout the clinical trial, the sponsor is responsible for accurately informing the local site investigators of the true historical safety record of the drug, device or other medical treatments to be tested, and of any potential interactions of the study treatment(s) with already approved treatments. This allows the local investigators to make an informed judgment on whether to participate in the study or not. The sponsor is also responsible for monitoring the results of the study as they come in from the various sites as the trial proceeds. In larger clinical trials, a sponsor will use the services of a data monitoring committee (DMC, known in the US as a data safety monitoring board). This independent group of clinicians and statisticians meets periodically to review the unblinded data the sponsor has received so far. The DMC has the power to recommend termination of the study based on their review, for example if the study treatment is causing more deaths than the standard treatment, or seems to be causing unexpected and study-related serious adverse events. The sponsor is responsible for collecting adverse event reports from all site investigators in the study, and for informing all the investigators of the sponsor's judgment as to whether these adverse events were related or not related to the study treatment.
==== Post-translational modification ==== Examples of post-translational modification include phosphorylation, myristoylation and glycosylation. For example, in the response to insulin, the phosphorylation of multiple enzymes, including glycogen synthase, helps control the synthesis or degradation of glycogen and allows the cell to respond to changes in blood sugar. Another example of post-translational modification is the cleavage of the polypeptide chain. Chymotrypsin, a digestive protease, is produced in inactive form as chymotrypsinogen in the pancreas and transported in this form to the stomach where it is activated. This stops the enzyme from digesting the pancreas or other tissues before it enters the gut. This type of inactive precursor to an enzyme is known as a zymogen or proenzyme.
== Clinical significance == Mice that have the lumican gene knocked out (Lum-/-) develop opacities of the cornea in both eyes and fragile skin. The lumican (LUM) gene was thought to be a candidate susceptibility gene for high myopia; however, a meta-analysis showed no association between LUM polymorphism and high myopia susceptibility in all genetic models studied. Lum knockout mice also have abnormal collagen in their heart tissue, with fewer and thicker fibrils. Mice deficient in both lumican and fibromodulin develop severe tendinopathy (tendon pathology), revealing the importance of these SLRPs in the development of correctly sized and aligned collagen fibers in tendon. Along with other extracellular matrix components, lumican expression was increased in equine flexor tendons six weeks after an injury. Lumican is present in the extracellular matrix of uteral tissues in fertile women. There is an increase of lumican during the proliferative to secretory phase of the endometrium. In menopausal endometrial tissue, the level of lumican expression decreases and is also low in pathological compared to normal endometrium. Lumican is highly expressed in pleural effusions (lung fluid) of patients with adenocarcinoma. Its expression was low in cancer cells but high in the extracellular matrix surrounding the tumor. Lumican expression was not associated with tumor grade or stage.
Negroponte examines Dimitri Mobengo Mugianis's long, clandestine career of treating heroin addicts with ibogaine. One of the five segments of "Hallucinogens DMT" (2012), Season 2, Episode 4 of Drugs, Inc. on National Geographic Channel, a former heroin user treats addicts with ibogaine in Canada. He himself used ibogaine to stop his abuse of narcotics. The "Underground Heroin Clinic" segment of "Addiction" (2013). Season 1, episode 7 of the HBO documentary series Vice examines the use of ibogaine to interrupt heroin addiction. The Ibogaine Safari (2014). A documentary by filmmaker Pierre le Roux which investigates the claims of painless withdrawal from opiates such as nyaope/heroin in South Africa by taking several addicts on an adventure "safari" while taking ibogaine. The documentary won the award for 'Best Documentary Short' at the 2014 Canada International Film Festival. Iboga Nights (2014). Directed by David Graham Scott. Dosed. A documentary by Tyler Chandler and Nicholas Meyers. Synopsis- After years of no success with prescription drugs, a suicidal Adrianne seeks help from underground healers with her depression, anxiety, and opioid addiction by utilizing illegal psychedelics like magic mushrooms and iboga. "Synthetic Ibogaine – Natural Tramadol" (2021). This episode of the documentary series Hamilton's Pharmacopeia on Vice on TV follows a struggling local addict to an ibogaine ritual. Lamar Odom Reborn (2022).
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.
It acts on the growth hormone secretagogue receptor, GHS-R1a, which is also the receptor for ghrelin. Binding triggers intracellular signaling that promotes growth hormone release from the pituitary. The interaction is the basis for its classification as a secretagogue.