A practical reference on ghrelin receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-03-22. Anything still debated is marked as such rather than presented as settled.
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 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。
| 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 |
Published animal and early human work describes growth hormone release that is separated from comparable rises in adrenocorticotropic hormone and cortisol. Prolactin changes are reported as small in the same studies. Selectivity is attributed to binding at the ghrelin receptor and to the downstream signaling that follows, rather than to differences in how quickly the peptide is cleared. Authors commonly label the compound selective rather than potent, because the same mass produces a smaller growth hormone response than some older secretagogues tested in parallel. Whether that profile holds across species and routes of administration remains an open question.
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.
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.
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.
== Retirement == Meurgues retired to Saint-Germain-de-Modéon, continuing to write articles in specialist magazines, sharing her knowledge in museology and scriptwriting, as well as restoring the family farm and creating an animal rescue refuge. She donated her scientific library to the Muséum d'Autun and is preparing a book Inventions et bricolages de la nature. She published Du jardin de Buffon à l'Afghanistan: mémoires d'une naturaliste in 2019. Geneviève Meurgues died on 21 December 2021, in her 91st year. According to her last wishes, her cremation was private and her ashes will be spread in the "Les Grands Bouchons" wood, where her vocation as a naturalist was born.
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Synthesis of pre-vitamin D3 in the skin involves UVB radiation, which effectively penetrates only the epidermal layers of skin. 7-Dehydrocholesterol absorbs UV light most effectively at wavelengths between 295 and 300 nm and, thus, the production of vitamin D3 will occur primarily at those wavelengths. The two most important factors that govern the generation of pre-vitamin D3 are the quantity (intensity) and quality (appropriate wavelength) of the UVB irradiation reaching the 7-dehydrocholesterol deep in the stratum basale and stratum spinosum. Light-emitting diodes (LEDs) can be used to produce the radiation. Another important consideration is the quantity of 7-dehydrocholesterol present in the skin. Under normal circumstances, ample quantities of 7-dehydrocholesterol (about 25–50 μg/cm2 of skin) are available in the stratum spinosum and stratum basale of human skin to meet the body's vitamin D requirements. 7-DHC insufficiency has been proposed as an alternate cause for Vitamin D deficiency.
Sources: en.wikipedia.org
Quisqualic acid is also associated with various neurological disorders such as epilepsy and stroke. Metabotropic glutamate receptors, also known as mGluRs are a type of glutamate receptor which are members of the G-protein coupled receptors. These receptors are important in neural communication, memory formation, learning and regulation. Like Glutamate, quisqualic acid binds to this receptor and shows even a higher potency, mainly for mGlu1 and mGlu5 and exert its effects through a complex second messenger system. Activation of these receptors leads to an increase in inositol triphosphate (IP3) and diacylglycerol (DAG) by the activation of phospholipase C (PLC). Eventually, IP3 diffuses to bind to IP3 receptors on the ER, which are calcium channels that eventually increase the Calcium concentration in the cell.
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Vanilla planifolia is a species of vanilla orchid native to Mexico, Central America, Colombia, and Brazil. It is one of the primary sources for vanilla flavouring, due to its high vanillin content. Common names include flat-leaved vanilla and West Indian vanilla (which is also used for the Pompona vanilla, V. pompona), though it is often simply referred to as vanilla. It was first scientifically named in 1808. Vanilla planifolia played a large role in the early rural economy throughout Mexico and by the 20th century had become a widely cultivated crop across the world. With the species' population in decline and its habitats being converted to other purposes, the IUCN has assessed Vanilla planifolia as Endangered.
Sources: en.wikipedia.org
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== Diagnosis == Lymphocytosis is usually detected when a complete blood count is obtained. If not provided the lymphocyte count can be calculated by multiplying the total white blood cell (WBC) count by the percentage of lymphocytes found in the differential count. The lymphocyte count can also be directly measured by flow cytometry.
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=== Recreational use === Over-the-counter pseudoephedrine has been misused as a psychostimulant. Six case reports and one case series of pseudoephedrine misuse have been published as of 2021. There is a case report of self-medication with pseudoephedrine for treatment of depression.
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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.
两者都是 GHS-R1a 激动剂，但 ipamorelin 在研究中显示出更高的生长激素释放选择性。早期资料显示它对皮质醇、催乳素与食欲的刺激弱于 GHRP-6。这些差异是相对程度，而非绝对区分。