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 2025-10-15. 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.
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.
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。
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。
| 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 |
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.
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.
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.
Lyophilized material is generally held at minus twenty degrees Celsius or lower, protected from moisture and light. Repeated excursions to room temperature cause condensation inside the vial and gradual moisture uptake, both of which shorten shelf life. Containers should be allowed to equilibrate before opening so that water does not condense on the solid. Dividing a batch into single-use aliquots reduces freeze-thaw cycling. Solid peptide handled this way is usually considered stable for months to years, while the same material in solution degrades on a much shorter timescale.
Common solvents for laboratory work include water, buffered saline, and dimethyl sulfoxide. Once dissolved, the peptide is exposed to hydrolysis and oxidation, and alkaline conditions accelerate breakdown. Low-binding plasticware and the addition of a carrier protein reduce losses to container surfaces, which can otherwise be substantial at low concentrations. Solutions are typically kept cold and used within days. Investigators working with the compound generally prepare fresh working dilutions rather than storing dilute stocks, and they avoid repeated warming of the same vial.
Intrinsic disorder can be either annotated from experimental information or predicted with specialized software. Disorder prediction algorithms can predict intrinsic disorder (ID) propensity with high accuracy (approaching around 80%) based on primary sequence composition, similarity to unassigned segments in protein x-ray datasets, flexible regions in NMR studies and physico-chemical properties of amino acids.
=== Integration of Biocon Biologics === On 6 December 2025, Biocon announced that it would fully integrate its biosimilars subsidiary Biocon Biologics Limited (BBL) as a wholly owned subsidiary, in a corporate action that valued BBL at US$5.5 billion and marked a pivot away from a previously planned initial public offering (IPO) of the biosimilars business. The company said the integration would simplify the group's corporate structure, remove the holding-company discount that had weighed on its valuation, and combine its generics and biosimilars operations into a single listed entity focused on diabetes, oncology and immunology. Under the plan, Biocon acquired the minority stakes held by Serum Institute Life Sciences, Tata Capital Growth Fund II and Activ Pine LLP through a share swap of 70.28 Biocon shares for every 100 BBL shares, priced at ₹405.78 per Biocon share. It also bought out the residual stake held by Mylan Inc. (Viatris) for US$815 million, comprising US$400 million in cash and US$415 million via a share swap, with the swap ratios based on independent valuations by EY. To fund the cash component payable to Viatris, Biocon raised approximately ₹4,150 crore (about US$460 million) through a qualified institutional placement (QIP) completed on 14 January 2026. The integration was completed by 31 March 2026, making Biocon Biologics a wholly owned subsidiary of Biocon Limited and creating a unified entity spanning biosimilars, insulins, generics and peptides. The leadership transition that followed is described under Corporate governance.
==== Don Cossacks in World War II ==== In April 1936, the earlier ban on Cossacks serving in the Red Army was lifted. Later in 1936, two existing Red Army cavalry divisions were re-designated as Don Cossacks. In 1939, a number of these regiments were issued with traditional Cossack uniforms, in ceremonial and field service versions. The dress of the Don Cossack units included dark-blue breeches with broad red stripes which had distinguished them prior to the Revolution. The Don Cossack Cavalry Corps saw extensive active service until 1943, after which its role diminished, as did that of the other remaining horse-mounted units in the Red Army. However Don Cossack cavalry was still in existence in 1945 and participated in the Victory Parade in Moscow. During World War II, the Don Cossacks mustered the largest single concentration of Cossacks within the German Army, the XVth SS Cossack Cavalry Corps, a great part of them former Soviet citizens. The XVth SS Cossack Cavalry Corps included the 1st Cossack Division and the 2nd Cossack Division. The majority of the Cossacks remained loyal to the Red Army. In the earliest battles, particularly the encirclement of Belostok, Cossack units such as the 94th Beloglisnky, 152nd Rostovsky and 48th Belorechensky regiments fought to their death. In the opening phase of the war, during the German advance towards Moscow, Cossacks were extensively used for raids behind enemy lines.
The ancestral Toll/TLR pathway, for example, is present in Anthozoa, but the key upstream receptor component of it is missing or has diverged in Hydra. The genus Hydra is missing some genes associated with larvae development, fluorescent proteins, and circadian rhythms that are normally found in the sea anemone genome. The genes eve and emx are absent in Hydra, even though they are present in Nematostella and hydrozoans. These genes are expressed during the larvae development. These losses in gene expression are thought to be signs of a substantial secondary gene loss during evolution. Hydra genome shows a preference towards proximal promoters. Thanks to this feature, many reporter cell lines have been created with regions around 500 to 2000 bases upstream of the gene of interest. Its cis-regulatory elements (CRE) are mostly located less than 2000 base pairs upstream from the closest transcription initiation site, but there are CREs located further away. Its chromatin has a Rabl configuration. There are interactions between the centromeres of different chromosomes and the centromeres and telomeres of the same chromosome. It presents a great number of intercentromeric interactions when compared to other cnidarians, probably due to the loss of multiple subunits of condensin II. It is organized in domains that span dozens to hundreds of megabases, containing epigenetically co-regulated genes and flanked by boundaries located within heterochromatin.
The polypeptide substrate binds to the surface of the serine protease enzyme such that the scissile bond is inserted into the active site of the enzyme, with the carbonyl carbon of this bond positioned near the nucleophilic serine. The serine -OH attacks the carbonyl carbon, and the nitrogen of the histidine accepts the hydrogen from the -OH of the [serine] and a pair of electrons from the double bond of the carbonyl oxygen moves to the oxygen. As a result, a tetrahedral intermediate is generated. The bond joining the nitrogen and the carbon in the peptide bond is now broken. The covalent electrons creating this bond move to attack the hydrogen of the histidine, breaking the connection. The electrons that previously moved from the carbonyl oxygen double bond move back from the negative oxygen to recreate the bond, generating an acyl-enzyme intermediate. Now, water comes into the reaction. Water replaces the N-terminus of the cleaved peptide, and attacks the carbonyl carbon. Once again, the electrons from the double bond move to the oxygen making it negative, as the bond between the oxygen of the water and the carbon is formed. This is coordinated by the nitrogen of the histidine, which accepts a proton from the water. Overall, this generates another tetrahedral intermediate. In a final reaction, the bond formed in the first step between the serine and the carbonyl carbon moves to attack the hydrogen that the histidine just acquired. The now electron-deficient carbonyl carbon re-forms the double bond with the oxygen. As a result, the C-terminus of the peptide is now ejected.
Sources: en.wikipedia.org
== Management == Red ear syndrome has proven difficult to treat. The most widely attempted medication is gabapentin, with one case series finding that seven of eight patients on gabapentin showed improvement in attack frequency and ear color. Smaller studies have reported some success in certain patients using amitriptyline, flunarizine, imipramine, verapamil, propranolol and ibuprofen. Appropriate medication may differ depending on the underlying cause of the individual's symptoms. Using an ice pack to cool the ear during an attack can provide temporary relief.
== External links == Overview of all the structural information available in the PDB for UniProt: P13693 (Human Translationally-controlled tumor protein) at the PDBe-KB. Overview of all the structural information available in the PDB for UniProt: P63028 (Mouse Translationally-controlled tumor protein) at the PDBe-KB.
== Cancer == Grape seed extract has been incorrectly described as a cancer cure on social media websites. There is no clinical evidence that grape seed extract is effective to treat cancer. In 2017, the Food and Drug Administration listed grape seed extract as a fake cancer cure that consumers should avoid.
== Covalent perchlorates == Although typically found as a non-coordinating anion, a few metal complexes are known. Hexaperchloratoaluminate and tetraperchloratoaluminate are strong oxidising agents. Several perchlorate esters are known. For example, methyl perchlorate is a high energy material that is a strong alkylating agent. Chlorine perchlorate is a covalent inorganic analog.
Sources: en.wikipedia.org
Heseltine was seen as more interested in large than in small and medium-sized companies, and in 1992 was only with difficulty persuaded to refer Lloyds Bank's takeover bid for Midland Bank to the Office of Fair Trading.
2020, I. S. Pires, D. A. Belcher, R. Hickey, C. Miller, A. K. Badu-Tawiah, J. H. Baek, P. W. Buehler, A. F. Palmer, “Novel manufacturing method for producing apohemoglobin and its biophysical properties,” Biotechnology and Bioengineering Jan;117(1):125-145. 2020, I. S. Pires, A. F. Palmer, “Tangential flow filtration of haptoglobin,” Biotechnology Progress Sep;36(5):e3010. 2020, C. J. Munoz, I. S. Pires, J. H. Baek, P. W. Buehler, A. F. Palmer, P. Cabrales, “A novel apo-hemoglobin-haptoglobin complex attenuates the pathobiology of circulating acellular hemoglobin and heme,” American Journal of Physiology Heart and Circulatory Physiology May 1;318(5):H1296-H1307.
==== Distribution ==== DMT easily crosses the blood–brain barrier. Studies on the llipophilicity of DMT have been contradictory – most studies find DMT to be either lipophilic or slightly lipophilic, but a 2023 study found it to be lipophobic. Several studies have described active transport and accumulation of DMT into rat and dog brains following peripheral administration. Similar active transport and accumulation processes likely occur in human brains and may concentrate DMT in brain by several-fold or more (relatively to blood), resulting in local concentrations in the micromolar or higher range. Such concentrations would be commensurate with serotonin brain tissue concentrations, which have been consistently determined to be in the 1.5–4 μmol/L range. The plasma protein binding of DMT is low at approximately 30%.
=== Selected articles === White, S. H. (1986). The physical nature of planar bilayer membranes. In Ion Channel Reconstitution (Chris Miller, Ed.). Plenum Press: New York. pp. 3–35. Wiener, M. C. and White, S. H. (1992). The structure of a fluid dioleoylphosphatidylcholine bilayer determined by joint refinement using x-ray and neutron diffraction data. III. The complete structure. Biophys. J. 61:434–447. White, S. H., Wimley, W. C., Ladokhin, A. S., and Hristova, K. (1998). Protein folding in membranes: Determining the energetics of peptide–bilayer interactions. Methods Enzymol. 295:62–87. White, S. H. and Wimley, W. C. (1999). Membrane protein folding and stability: Physical principles. Annu. Rev. Biophys. Biomolec. Struct. 28:319–365 Hessa, T., Meindl-Beinker, N. M., Bernsel, A., Kim, H., Sato, Y., Lerch, M. B., Nilsson, I., White, S. H., and von Heijne, G. (2007). The molecular code for transmembrane-helix recognition by the Sec61 translocon. Nature 450:1026-1030. Cymer, F., von Heijne, G., & White S.H. (2015). Mechanisms of integral membrane protein insertion and folding. J Mol Biol 427:999-1022. Roussel, G., Lindner, E., & White, S. H. (2022). Topology of the SecA ATPase Bound to Large Unilamellar Vesicles. Journal of Molecular Biology, 434(12), 167607.
. In conventional chromatography, separation of similar compounds can be improved by gradient elution. In MEKC, however, techniques must be used to extend the elution range to separate strongly retained analytes. Elution ranges can be extended by several techniques including the use of organic modifiers, cyclodextrins, and mixed micelle systems. Short-chain alcohols or acetonitrile can be used as organic modifiers that decrease
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.
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。