growth hormone secretagogue is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-01-29. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 formula | C38H49N9O5 | Value for the free base |
| Molar mass | 711.9 g/mol | Calculated from the formula |
| Appearance | White to off-white powder | Typical lyophilized form |
| Mechanism class | Ghrelin receptor agonist | Also described as a secretagogue |
| Half-life | About 2 hours | Reported for human circulation |
Lyophilized ipamorelin is generally held at minus twenty degrees Celsius or colder, protected from light and moisture. In solution the peptide is less stable, and degradation proceeds through hydrolysis of the amide backbone, oxidation of the histidine residue, and aggregation. Repeated freeze-thaw cycles accelerate these processes, so dividing material into single-use aliquots before freezing is common practice in research settings. Buffered formulations near neutral pH tend to show the slowest degradation, while strongly acidic or basic conditions raise hydrolysis rates. Stability data specific to ipamorelin are sparse, and much guidance is extrapolated from other short peptides.
Quality control for research-grade ipamorelin is not governed by a single harmonized pharmacopeial monograph, so certificates of analysis vary between suppliers. Common tests include appearance, solubility, water content, peptide content by quantitative amino acid analysis, and residual counterion measurement. Independent verification by an outside laboratory is often used to confirm identity and purity claims. Salt form, counterion content, and residual solvent levels are frequently unspecified, which complicates direct comparison between lots and leaves reproducibility partly unresolved.
对 ipamorelin 的常规表征以反相高效液相色谱测定纯度，检测波长多设为 214 nm，因为肽键在该波长有较强吸收。身份确认通常借助电喷雾电离质谱或串联质谱，将实测分子量与理论值逐项比对。序列层面可用肽图分析或氨基酸分析进一步验证。这些手段组合起来，可以分别覆盖纯度、身份与序列三个不同层次的信息。
杂质谱一般包含缺失序列片段、差向异构体、氧化产物以及残留溶剂或反离子，其中组氨酸与芳香残基的氧化常被重点关注。反相色谱中这类杂质往往紧邻主峰洗脱，因此方法需要足够的分离度并经过系统适用性验证。纯度百分比的解读依赖于检测波长与梯度条件，不同实验室公布的数字不宜直接横向比较。参考标准品有助于跨批次对照，但其自身赋值同样需要可追溯来源。
Identity and purity assessment for a research peptide of this kind typically combines reversed-phase high-performance liquid chromatography with mass spectrometry. The chromatographic run separates related impurities and yields a purity percentage, while electrospray ionization or matrix-assisted laser desorption mass spectrometry confirms the expected molecular mass. Amino acid analysis or tandem mass spectrometry sequencing can add confidence when material is intended for quantitative work. Laboratories differ in how they calculate and report purity, so figures from different sources are not always directly comparable.
Lyophilized material is generally stored cold and dry, with desiccant, and protected from light. In solution the peptide is more vulnerable: the histidine side chain can oxidize, and repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. A mildly acidic aqueous buffer is often used for short-term handling because it limits several degradation routes. Accurate prediction of long-term stability under a given set of conditions is difficult, and published stability data remain sparse.
Published discussion of this compound is uneven. Some references describe it as a tool for probing growth hormone regulation, while others focus on analytical characterization or on comparisons with related secretagogues. Statements about selectivity, half-life and potency often trace back to a small number of original reports that later authors cite secondhand. Readers evaluating a claim should therefore check whether a figure reflects a direct measurement or a repeated citation, and whether the underlying study was conducted in animals, in isolated cells or in human volunteers.
In the late autumn of 1980, having spent several years on spiritual pursuits and then gradually returning to music (including playing guitar for David Bowie, Brian Eno, Peter Gabriel and Daryl Hall; pursuing an experimental solo career; and leading the instrumental new wave band The League of Gentlemen), Fripp decided to form a new "first division" rock group. Having recruited Bruford as drummer, Fripp then asked the American singer and guitarist Adrian Belew, who had previously played with Bowie and Frank Zappa, to join; this was the first time Fripp would actively seek collaboration with another guitarist in a band, and therefore indicative of his desire to create something unlike any of his previous work. After touring with Talking Heads, Belew agreed to join and also become the band's lyricist. Bruford's suggestion of bassist Jeff Berlin of Bruford was rejected as Fripp thought his playing was "too busy", so auditions were held in New York; on the third day, Fripp left after roughly three auditions, only to return several hours later with session bassist Tony Levin (who got the job after playing a single chorus of "Red"). Fripp later confessed that, had he known that Levin (whom Fripp had played with in Peter Gabriel's group) was available and interested, he would have selected him without holding auditions. Fripp named the new quartet Discipline, and they went to England to rehearse and write new material. They made their live debut at Moles Club in Bath, Somerset on 30 April 1981, and completed a short UK tour supported by the Lounge Lizards.
The etymology of the various words for tea reflects the history of transmission of tea drinking and trade from China. Nearly all of the words for tea worldwide fall into three broad groups: te, cha and chai, present in English as tea, cha or char, and chai. The earliest of the three to enter English is cha, which came in the 1590s via the Portuguese, who traded in Macao and picked up the Cantonese pronunciation of the word. The more common tea form arrived in the 17th century via the Dutch, who acquired it via trades from their colonial empire either indirectly from the Malay teh, or directly from the tê pronunciation in Min Chinese. The third form chai (meaning "spiced tea") originated from a northern Chinese pronunciation of cha, which travelled via the overland Silk Road to Central Asia and Persia, where it picked up a Persian ending yi. The Chinese word for tea itself was perhaps derived from the non-Sinitic languages of the botanical homeland of the tea plant in southwest China and northeastern Burma (modern-day Kachin and Shan), possibly from an archaic Austro-Asiatic root word *la, meaning "leaf".
Because vitamin K aids mechanisms for blood clotting, its deficiency may lead to reduced blood clotting, and in severe cases, can result in increased bleeding and increased prothrombin time. Normal diets are usually not deficient in vitamin K, indicating that deficiency is uncommon in healthy children and adults. An exception may be infants who are at an increased risk of deficiency regardless of the vitamin status of the mother during pregnancy and breast feeding due to poor transfer of the vitamin to the placenta and low amounts of the vitamin in breast milk. Secondary deficiencies can occur in people who consume adequate amounts, but have malabsorption conditions, such as cystic fibrosis or chronic pancreatitis, and in people who have liver damage or disease. Secondary vitamin K deficiency can also occur in people who have a prescription for a vitamin K antagonist drug, such as warfarin. A drug associated with increased risk of vitamin K deficiency is cefamandole, although the mechanism is unknown.
== Structural studies == As of late 2007, 15 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1S5B, PDB: 1S5C, PDB: 1S5D, PDB: 1S5E, PDB: 1S5F, PDB: 1SGK, PDB: 1TOX, PDB: 1XDT, PDB: 1XK9, PDB: 1ZM3, PDB: 1ZM4, PDB: 1ZM9, PDB: 2A5D, PDB: 2A5F, and PDB: 2A5G.
== Etymology == The word Portugal derives from Latin Portus Cale, a Roman name meaning 'port of Cale', itself the origin of the name of the Portuguese city of Porto, while Cale was a town on the Douro. There is no consensus on the etymology of Cale. It could derive from the pre-Indo-European word Kala, meaning 'shelter' or 'refuge', passed into the Celtic language in the form Cale, with the meaning of 'land' or 'mountain'. The ethnonym Calaico/a then came from the Gallaeci, Celtic peoples of northwestern Iberia, and came to mean 'one of the land' or 'one of the place. During the Middle Ages, the region around Portus Cale became known by the Visigoths as Portucale and by the Suebi as Parochiale. The name Portucale evolved into Portugale; by the 11th and 12th centuries Portugal referred to the region between the Douro and Minho rivers.
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== Hosts and disease development == Penicillium expansum has a wide host range, causing similar symptoms on fruits which include apples, pears, cherries, and citrus. Initial infection most often occurs at sites of fruit injury, such as bruises or puncture wounds. Although infections may start in the field, infected spots often become evident post-harvest, and expand while fruit is in storage. Infected areas are clearly delineated and light brown, and soft decaying tissue can be easily "scooped" out of the surrounding healthy tissue. Spore masses later appear on the surfaces of infected fruit, initially appearing as white mycelium, then turning blue to blue-green in color as the asexual spores mature. Fruit affected by P. expansum typically has an earthy, musty odor. Lesions measure 1–1.25 inches in diameter eight to ten weeks after infection if kept under cold storage conditions. Age factors into P. expansum infection, in that overripe or mature fruits are most susceptible to infection, while those picked underripe are less likely to become infected. In apples, the colors of the lesions may vary with variety, from lighter-brown on green and yellow apple varieties, to dark-brown on the deeper-red and other darker-color varieties. Varieties particularly susceptible to P. expansum infection include McIntosh, Golden Supreme, and Golden Delicious. Both sweet and sour cherries are affected by P. expansum. Cherry varieties found to be particularly susceptible to P. expansum infection were mainly early varieties, including Navalinda and Burlat.
In October 2023, the US Food and Drug Administration (FDA) approved Vamorolone (Agamree) as a Treatment for Duchenne muscular dystrophy. Catalyst Pharmaceuticals holds the exclusive North American license and commercial rights. In March 2024, the FDA approved givinostat (Duvyzat), an oral medication, to be used in the treatment of Duchenne muscular dystrophy in people aged six years and older. Givinostat is the first nonsteroidal drug to receive FDA approval for the treatment of all genetic variants of Duchenne muscular dystrophy. Functioning as a histone deacetylase (histone deacetylase (HDAC) inhibitor, givinostat operates by targeting pathogenic processes within the body, ultimately leading to a reduction in inflammation and muscle loss associated with the disease.
1993/931) Friendly Societies Act 1992 (Transitional and Consequential Provisions and Savings) Regulations 1993 (S.I. 1993/932) Finance Act 1991, section 58, (Commencement No. 3) Regulations 1993 (S.I. 1993/933) Legal Aid in Criminal and Care Proceedings (Costs) (Amendment) Regulations 1993 (S.I. 1993/934) Housing Benefit and Community Charge Benefit (Subsidy) (No. 2) Order 1993 (S.I. 1993/935) Certification Officer (Amendment of Fees) Regulations 1993 (S.I. 1993/936) Further Education (Exclusion of Land from Transfer) (No. 2) Order 1993 (S.I. 1993/937) Land Registry Trading Fund Order 1993 (S.I. 1993/938) Land Registration (Determination of Costs) Order 1993 (S.I. 1993/939) Local Government Administration (Matters Subject to Investigation) Order 1993 (S.I. 1993/940) Local Elections (Variation of Limits of Candidates' Election Expenses) (Northern Ireland) Order 1993 (S.I. 1993/941) Copyright (Application to Other Countries) Order 1993 (S.I. 1993/942) Performances (Reciprocal Protection) (Convention Countries) Order 1993 (S.I. 1993/943) European Communities (Definition of Treaties) (International Railway Tariffs Agreements) Order 1993 (S.I. 1993/944) Insurance Companies (Accounts and Statements) (Amendment) Regulations 1993 (S.I. 1993/946) Patents (Supplementary Protection Certificate for Medicinal Products) (Amendment) Rules 1993 (S.I. 1993/947) Chessington Computer Centre Trading Fund Order 1993 (S.I. 1993/948) Income Tax (Interest Relief) (Qualifying Lenders) Order 1993 (S.I. 1993/949) Capital Gains Tax (Gilt-edged Securities) Order 1993 (S.I.
=== αvβ6-integrin target === The abundance of αvβ6-integrin on most adult human cell types and respective tissues is low. It is however overexpressed in the context of several medical conditions, such as cancer or fibrosis, particularly idiopathic pulmonary fibrosis. In line with the finding that αvβ6-integrin is expressed by epithelial cells, an elevated density of the protein is observed on the cell surfaces of many carcinomas (synonymous to cancers of epithelial origin). Hence, 68Ga-Trivehexin can be used for PET imaging of αvβ6-integrin positive cancers (i.e., those whose cells possess a sufficiently high density of αvβ6 on their surface), including but not limited to pancreatic ductal adenocarcinoma, non-small cell lung cancer, squamous cell carcinomas (SCC) of different origin (most notably, oral and esophageal SCC), as well as breast, ovarian, and bladder cancer. In colorectal cancer, expression of αvβ6-integrin is higher in the more aggressive forms and correlated with reduced overall survival. 68Ga-Trivehexin has a high binding affinity to αvβ6-integrin (IC50 = 0.047 nM). Its affinity to other RGD-binding integrins is much lower (IC50 for αvβ3, αvβ8, and α5β1 are 2.7, 6.2, and 22 nM, respectively; note that for IC50, higher values mean lower affinity), resulting in a high selectivity for αvβ6-integrin.
Sources: en.wikipedia.org
It has not been approved as a therapeutic by major regulators, and the human trial record is small and dated. Material available today is mostly sold as a research chemical for laboratory use. Approval and restriction status varies by country.
It binds the ghrelin receptor, known as the growth hormone secretagogue receptor type 1a. Activation of that receptor triggers signaling that leads to growth hormone release. Selectivity for growth hormone over cortisol and prolactin is the property most often cited for this compound.
Published estimates place the circulating half-life at roughly two hours in humans. Clearance involves peptidase activity and renal handling. Because the peptide is short-lived, release patterns after administration are usually described as pulsatile rather than sustained.
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.