This is a working overview of ipamorelin, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-31. Anything still debated is marked as such rather than presented as settled.
One distinguishing feature reported in animal studies is selectivity. Ipamorelin stimulated growth hormone release with limited elevation of adrenocorticotropic hormone or cortisol compared with earlier secretagogues such as GHRP-6. This pattern has been described as more selective for the growth hormone axis. The finding comes mainly from preclinical work, and the degree to which it holds across species and doses is not fully settled. Reports also describe effects on gastric motility in animal models, suggesting activity outside the pituitary, though the clinical relevance of this observation is uncertain.
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.
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 |
|---|---|---|
| Molecular class | Synthetic pentapeptide | Chain of five amino acid residues |
| Molecular mass | Approximately 712 Da | Consistent with a five-residue chain |
| Receptor target | GHS-R1a | Growth hormone secretagogue receptor |
| Primary action | Growth hormone release | Pituitary somatotroph stimulation |
| Research origin | Developed in the 1990s | Small-peptide secretagogue program |
现有文献多来自小规模、短期的研究，涉及生长激素缺乏、术后肠麻痹等方向。长期使用是否导致受体脱敏，以及重复给药后效应是否衰减，仍属开放问题。不同研究之间的剂量、给药途径和受试者特征差异较大，因此结论外推需谨慎。关于临床获益的确切证据尚不充分，需要更大规模的对照试验来澄清。
Ipamorelin 是一种合成五肽，在 20 世纪 90 年代被报道为生长激素促分泌剂。其结构基于胃饥饿素受体激动剂的设计思路，但并非天然激素。早期药理学研究显示，它可刺激垂体释放生长激素，而对应激激素轴的影响相对较小。该化合物常被用作研究生长激素调节通路的工具分子。
在机制层面，ipamorelin 与生长激素促分泌受体 1a 型结合，该受体也介导胃饥饿素的多种效应。受体激活后，细胞内信号促进生长激素从垂体前叶释放。由于对促肾上腺皮质激素和皮质醇的刺激较弱，它被视为选择性较高的促分泌剂。这种选择性在动物模型和少量人体研究中被观察到，但人体数据仍然有限。
Structural features distinguish the molecule from earlier secretagogues. An alpha-aminoisobutyric acid residue near the N-terminus and a D-naphthylalanine substitution increase receptor affinity, while C-terminal amidation improves resistance to exopeptidases. These modifications are associated with reduced stimulation of appetite and of the hypothalamic-pituitary-adrenal axis compared with hexarelin or growth hormone releasing peptide-6. Whether the same profile applies at every dose level studied is a matter of ongoing investigation rather than settled consensus.
Ipamorelin is a synthetic pentapeptide that acts as an agonist at the ghrelin receptor, also called the growth hormone secretagogue receptor type 1a. Its sequence incorporates non-natural residues, which slows enzymatic breakdown relative to short native peptides. In laboratory and early clinical work the compound is described as a selective growth hormone secretagogue because it raises growth hormone with comparatively little effect on other pituitary outputs. The degree to which that selectivity holds across species and dosing regimens remains an open question in the published literature.
Signal transduction begins when the peptide binds GHSR-1a on pituitary somatotrophs. The receptor couples to Gq/11 proteins, activating phospholipase C, which cleaves phosphatidylinositol bisphosphate into inositol trisphosphate and diacylglycerol. Inositol trisphosphate releases calcium from intracellular stores, and the resulting rise in cytosolic calcium drives growth hormone vesicle fusion. Concurrent Gs coupling and cyclic AMP elevation have also been reported, and the relative contribution of each arm to the overall secretory response is not fully settled.
THAP, DHAP, and a mixture of 2-aza-2-thiothymine and phenylhydrazine have been identified as matrices that could be used to minimize loss of sialic acid during MALDI MS analysis of glycosylated peptides. It has been reported that a reduction in loss of some post-translational modifications can be accomplished if IR MALDI is used instead of UV MALDI. Besides proteins, MALDI-TOF has also been applied to study lipids. For example, it has been applied to study the catalytic reactions of phospholipases. In addition to lipids, oligonucleotides have also been characterised by MALDI-TOF. For example, in molecular biology, a mixture of 5-methoxysalicylic acid and spermine can be used as a matrix for oligonucleotides analysis in MALDI mass spectrometry, for instance after oligonucleotide synthesis.
==== Menstrual bleeding ==== Tranexamic acid is sometimes used to treat heavy menstrual bleeding. When taken by mouth it both safely and effectively treats regularly occurring heavy menstrual bleeding and improves quality of life. Another study demonstrated that the dose does not need to be adjusted in females who are between ages 12 and 16. In a 10-year study, tranexamic acid and other oral medicines (mefenamic acid) were found to be as effective as the levonorgestrel intrauterine coil; the same proportion of women had not had surgery for heavy bleeding and had similar improvements in their quality of life.
US policy regarding media freedom was much more restrictive than in the Vietnam War. The policy had been spelled out in a Pentagon document entitled Annex Foxtrot. Most of the press information came from briefings organized by the military. Only selected journalists were allowed to visit the front lines or conduct interviews with soldiers. Those visits were always conducted in the presence of officers, and were subject to both prior approval by the military and censorship afterward. This was ostensibly to protect sensitive information from being revealed to Iraq. This policy was heavily influenced by the military's experience with the Vietnam War, in which public opposition within the US grew throughout the war's course. It was not only the limitation of information in the Middle East; media were also restricting what was shown about the war with more graphic depictions like Ken Jarecke's image of a burnt Iraqi soldier being pulled from the American AP wire whereas in Europe it was given extensive coverage. Two BBC journalists, John Simpson and Bob Simpson (no relation), defied their editors and remained in Baghdad to report on the war's progress. They were responsible for a report which included an "infamous cruise missile that travelled down a street and turned left at a traffic light." Alternative media outlets provided views opposing the war. Deep Dish Television compiled segments from independent producers in the US and abroad, and produced a 10-hour series that was distributed internationally, called The Gulf Crisis TV Project.
=== Diseases === The moth is susceptible to viral diseases including nucleopolyhedrovirus (NPV). This is a naturally occurring virus whose natural hosts include Lepidoptera, arthropods, and Hymenoptera. From the family Baculoviridae, it is a type of Alphabaculovirus and its genome is 80–180kb long. NPVs are commonly used as pesticides for the cabbage looper. There are numerous NPVs, many of which were isolated from the cabbage looper or the alfalfa looper. NPVs vary in infectivity and virulence. For example, the AcMNPV isolates are more infectious than the TnSNPV (the SNPV/single nuclear polyhedrosis virus specific to the cabbage looper) isolates in the first instar, while the TnSNPV isolates produced more occlusion bodies, protein structures that protect the virus and increase long term infectivity. TnSNPVs are their most lethal during the third and fourth instars; they have detrimental effects such as delayed development, reduced egg production, and fewer hatched eggs. These effects are significantly diminished when the larvae are infected during the fifth instar, suggesting that the earlier infection is more effective. Bacillus thuringiensis (Bt) is a gram-positive soil bacterium from the phylum Bacillota. It is often used as a biological insecticide for numerous insect pests, including the cabbage looper, and reduces both growth rate and pupal weight. The cabbage looper has demonstrated resistance to Bt, specifically the toxin Cry1Ac, due to an autosomal recessive allele.
== External links == International Chemical Safety Card 0578 NIOSH Pocket Guide to Chemical Hazards U.S. OSHA info on THF Archived 2017-05-02 at the Wayback Machine "2-Methyltetrahydrofuran, An alternative to Tetrahydrofuran and Dichloromethane". Sigma-Aldrich. Retrieved 2007-05-23.
Sources: en.wikipedia.org
Narrated by Alun Lewis, directed by Gary Leach, produced by Geoff Deehan, produced by Sandlin Productions 24 November The Dyslexic Engineer, about Ben Bowlby, born on 2 November 1966; his VS91 car at Snetterton Circuit, with a Vauxhall Astra engine, with footage mostly from the end of the earlier documentary in September 1990; his studies at the Polytechnic of East London; Richard Bowlby, his father from Hampstead, who also realised that he was dyslexic; Rosalind Rathouse, his former remedial teacher; Roy Greenfield, a retired maths teacher from King Alfred School, London, who believed that perhaps people would adapt to mathematics more if the subject was taught later in life, as people are often put off the subject at secondary school; Ben gained nine O-levels but couldn't acquire Mathematics A-level above grade E after, two attempts; Xenia Bowlby; his polytechnic course tutor, Alan Slawson, and limited-slip differentials; his car raced in the Clubman (racing car class); he was sponsored by Ripspeed clothing and Spax Performance shock absorbers; Eric Broadly of Lola Cars; he joined Lola Cars in October 1991; he had attempted to gain a place at Lancaster University to study Engineering; Mike Blanchet of Lola Cars; empirical research in designing and building motor racing cars; Mark Williams, head of Formula 3000 at Lola Cars. Narrated by Ian Holm, produced by Michael Proudfoot, directed by Patrick Uden, made by Uden Associates.
“A New Pentacyclic Pyrylium Fluorescent Probe that Responds to pH Imbalance During Apoptosis”. Chem. Sci., 2020,11, 12695-12700. https://doi.org/10.1039/D0SC02623A. A. Mal, S. Vijayakumar, R. K. Mishra, J. Jacob, R. S. Pillai, B. S. Dileep Kumar and Ajayaghosh, Ayyappanpillai (2020). “Supramolecular Surface Charge Regulation in Ionic Covalent Organic Nanosheets for Reversible Exfoliation and Controlled Bacterial Growth”. Angew. Chem., Int. Ed. 2020, 59, 8713-8719. https://doi.org/10.1002/anie.201912363. G, Das.; S, Cherumukkil.; A, Padmakumar.; V, B, Banakar.; V, K, Praveen.; and Ajayaghosh, Ayyappanpillai (2021). “Tweaking a BODIPY Spherical Self-Assembly to 2D Supramolecular Polymers Facilitates Excited State Cascade Energy Transfer”. Angew. Chem. Int. Ed. 2021, 60, 7851-7938. https://doi.org/10.1002/ange.202015390. A, Nirmala.; I, Mukkatt.; S, Shankar.; and Ajayaghosh, Ayyappanpillai (2021). “Thermochromic Color Switching to Temperature Controlled Volatile Memory and Counter Operations with Metal-Organic Complexes and Hybrid Gels”. Angew. Chem., Int. Ed. 2021, 60, 455-465. https://doi.org/10.1002/anie.202011580. I, Mukkatt.; A, P, Mohanachandran.; A, Nirmala.; D, Patra.; P, A, Sukumaran.; R, S, Pillai.; R, B, Rakhi.; S, Shankar.; and Ajayaghosh, Ayyappanpillai (2022). “Tunable Capacitive Behavior in Metallopolymer-based Electrochromic Thin Film Supercapacitors”. ACS Appl. Mater. Interfaces, 2022, 14, 31900-31910. https://doi.org/10.1021/acsami.2c05744
== Chemistry == Clomipramine is a tricyclic compound, specifically a dibenzazepine, and possesses three rings fused together with a side chain attached in its chemical structure. Other dibenzazepine TCAs include imipramine, desipramine, and trimipramine. Clomipramine is a derivative of imipramine with a chlorine atom added to one of its rings and is also known as 3-chloroimipramine. It is a tertiary amine TCA, with its side chain-demethylated metabolite desmethylclomipramine being a secondary amine. Other tertiary amine TCAs include amitriptyline, imipramine, dosulepin (dothiepin), doxepin, and trimipramine. The chemical name of clomipramine is 3-(3-chloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)-N,N-dimethylpropan-1-amine and its free base form has a chemical formula of C19H23ClN2 with a molecular weight of 314.857 g/mol. The drug is used commercially almost exclusively as the hydrochloride salt; the free base has been used rarely. The CAS Registry Number of the free base is 303-49-1 and of the hydrochloride is 17321–77–6.
== Research == Oral nalmefene was under development for the treatment of pathological gambling, interstitial cystitis, pruritus, rheumatoid arthritis, shock, and smoking withdrawal, but development was discontinued for all of these indications. Formulations of nalmefene for use by intramuscular injection, intravenous injection, and intranasal administration are in late-stage development for the treatment of opioid-related disorders. Nalmefene might be useful to treat cocaine addiction.
== Myths == Some popular beliefs attached to weight loss have been shown to either have less effect on weight loss than commonly believed or are actively unhealthy. According to Harvard Health, the idea of metabolic rate being the "key to weight" is "part truth and part myth" as while metabolism does affect weight loss, external forces such as diet and exercise have an equal effect. They also commented that the idea of changing one's rate of metabolism is under debate. Diet plans in fitness magazines are also often believed to be effective but may actually be harmful by limiting the daily intake of important calories and nutrients which can be detrimental depending on the person and are even capable of driving individuals away from weight loss.
Sources: en.wikipedia.org
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.
In animal studies it showed greater selectivity for growth hormone release, with less effect on cortisol and adrenocorticotropic hormone than compounds such as GHRP-6. This selectivity is one of the most frequently cited features in preclinical literature. Whether the same profile applies in other contexts is not fully established.
The receptor-level events are reasonably well described, but the full range of downstream effects is not. Studies have reported activity in tissues beyond the pituitary, including the gut. How these observations translate across species and conditions remains an open question.
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.