If you have been reading about pentapeptide 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 2025-08-19. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| 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.
Identity and purity assessment of ipamorelin relies mainly on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometers, a wavelength where the peptide backbone absorbs. Mass confirmation is typically obtained by electrospray ionization mass spectrometry or by liquid chromatography coupled to mass spectrometry, comparing the observed mass with the calculated value. Amino acid analysis and peptide mapping after enzymatic digestion can confirm the sequence. Impurity profiles include deletion peptides, truncated fragments, and oxidation products, reported as relative area percentages.
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。
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.
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.
The SC was decommissioned in 1990, after having been in operation for more than three decades. As a consequence, the collaboration decided to relocate the ISOLDE facility to the Proton Synchrotron, and place the targets in an external beam from its 1 GeV booster. The construction of the new ISOLDE experimental hall started about three months prior to the decommissioning of the SC. With the relocation also came several upgrades. The most notable being the installation of two new magnetic dipole mass separators. One general-purpose separator with one bending magnet and the other one is a high-resolution separator with two bending magnets. The latter one is a reconstructed version of the ISOLDE 3. The first experiment at the new facility, known as ISOLDE PSB, was performed on 26 June 1992. In May 1995, two industrial robots were installed in the facility to handle the targets and ion sources units without human intervention.
When B cells and T cells are activated by a pathogen, memory B-cells and T- cells develop, and the primary immune response results. Throughout the lifetime of an animal, these memory cells will "remember" each specific pathogen encountered, and can mount a strong secondary response if the pathogen is detected again. The primary and secondary responses were first described in 1921 by English immunologist Alexander Glenny although the mechanism involved was not discovered until later. This type of immunity is both active and adaptive because the body's immune system prepares itself for future challenges. Active immunity often involves both the cell-mediated and humoral aspects of immunity as well as input from the innate immune system.
=== Synthesis in nuclear explosions === The analysis of the debris at the 10-megaton Ivy Mike nuclear test was a part of long-term project, one of the goals of which was studying the efficiency of production of transuranium elements in high-power nuclear explosions. The motivation for these experiments was as follows: synthesis of such elements from uranium requires multiple neutron capture. The probability of such events increases with the neutron flux, and nuclear explosions are the most powerful neutron sources, providing densities on the order 1023 neutrons/cm2 within a microsecond, i.e. about 1029 neutrons/(cm2·s). For comparison, the flux of the HFIR reactor is 5×1015 neutrons/(cm2·s). A dedicated laboratory was set up right at Enewetak Atoll for preliminary analysis of debris, as some isotopes could have decayed by the time the debris samples reached the U.S. The laboratory was receiving samples for analysis, as soon as possible, from airplanes equipped with paper filters which flew over the atoll after the tests. Whereas it was hoped to discover new chemical elements heavier than fermium, those were not found after a series of megaton explosions conducted between 1954 and 1956 at the atoll.
Hazard research is published: a study demonstrates that exposure to microplastics causes neurobehavioral and immunological changes in mammals (mice), varying by age (1 Aug), a study shows people can't reliably detect speech deepfakes with detection for years-old AI software being at 73% (2 Aug), researchers report an unprecedented accuracy of reading keystrokes from audio of smartphone-recordings or video-chats (7 Aug), a global survey study of climate policy researchers finds these experts substantially doubt the prevailing green growth narrative, "underscor[ing] the importance of considering alternative post-growth perspectives" that include approaches of agrowth and degrowth (7 Aug), a study investigating results from a GBD study finds that while age-standardized number of cardiovascular deaths from PM air pollution have declined during the past three decades, all-age DALYs increased by 31%, reaching ~89 million years in 2019, to which years of potential life lost contributed the most with ~82 million years lost during this year (9 Aug), a study indicates a third of men worldwide are infected with genital human papillomavirus which is relevant to cancer prevention, long-term sequelae and vaccination (16 Aug), a preprint confirms smart bulbs may often be one of the weakest links that can be used to gain access to a nearby person's Wi-Fi network (17 Aug), a GBD study projects cure-less osteoarthritis to affect nearly one billion people by 2050 (21 Aug), a study indicates that all types of straws, including paper straws, except for those made of stainless steel and few exceptions, expose people and their environments to PFAS (24 Aug), a study indicates cannabis is often a source of exposure to the contaminants cadmium and lead (30 Aug), researchers demonstrate Web browser extensions can gather passwords from input fields of many of the largest websites (30 Aug). Promising results of health and medical research are reported: mice- and dogs-tested AOH1996 against cancer growth and for combination with other anti-cancer agents (1 Aug), a mice-tested engineered probiotic against autoimmunity in the brain as in multiple sclerosis (9 Aug), mice-tested engineered bacteria to detect cancer DNA (10 Aug), a review finds that of the compared insecticide-treated nets to prevent malaria, chlorfenapyr-pyrethroid – or PNP combinations – are overall the most effective and address insecticide-resistance (16 Aug), mice-tested clovibactin against antibiotic-resistant bacterial pathogens (22 Aug), two brain implants achieve milestone performances in words per minute and median word error rate (23 Aug), mice-tested phytosterols – or cholesterol-imbalance-correction more broadly – against aging-associated hearing loss (24 Aug), a pig-tested artificial kidney transplant containing a bioreactor containing renal cells for renal replacement therapy (29 Aug), a Raman-based first test for diagnosing ME/CFS and differentiating between severities with potential relevance to long COVID (31 Aug).
Quisqualic acid is an agonist of the AMPA, kainate, and group I metabotropic glutamate receptors. It is one of the most potent AMPA receptor agonists known. It causes excitotoxicity and is used in neuroscience to selectively destroy neurons in the brain or spinal cord. Quisqualic acid occurs naturally in the seeds of Quisqualis species. Research conducted by the USDA Agricultural Research Service, has demonstrated quisqualic acid is also present within the flower petals of zonal geranium (Pelargonium x hortorum) and is responsible for causing rigid paralysis of the Japanese beetle. Quisqualic acid is thought to mimic L-glutamic acid, which is a neurotransmitter in the insect neuromuscular junction and mammalian central nervous system.
Sources: en.wikipedia.org
=== Near-death experience === Most people who were able to remember their dreams during ketamine anesthesia report near-death experiences (NDEs) when the broadest possible definition of an NDE is used. Ketamine can reproduce features that commonly have been associated with NDEs. A 2019 large-scale study found that written reports of ketamine experiences had a high degree of similarity to written reports of NDEs in comparison to other written reports of drug experiences.
=== Acquisitions === Grifols acquired its first group of plasma donation centers (43 in the U.S.) in 2002, taking over the company SeraCare, now known as Biomat. The following year, Grifols acquired Alpha Therapeutic Corporation-Mitsubishi, including its plasma fractionation plant in Los Angeles, California. In 2011, Grifols acquired the North American company Talecris Biotherapeutics, making Grifols the third-largest manufacturer of plasma-derived medicines in the world. Grifols acquired Novartis' blood transfusion diagnostics unit, based in Emeryville, California, in 2014. It was a part of Chiron, which had been acquired by Novartis in 2006. Grifols grew its transfusion medicine business with the acquisition of Hologic’s transfusion unit in 2017, leading the company’s creation of reagents and instrumentation based on NAT (nucleic acid testing) technology. In 2018, Grifols acquired the German company Haema and its network of donation centers and, in 2019, Grifols grew its network of donation centers with the addition of Interstate Blood Bank Inc. Today, the company has approximately 400 donation centers worldwide, most of them located in the U.S. Following a major equity investment in 2015, Grifols acquired the remaining shares of Alkahest in 2020 to help enhance the company’s discovery research and development to identify therapies based upon an understanding of the human plasma proteome. In 2021, the company acquired the remaining capital of GigaGen, a U.S.
== Function == IGFBP-3 was first isolated, characterized, and quantitated in human plasma, in 1986. It has well-documented functions in the circulation, in the extracellular environment, and inside cells. It is the main IGF transport protein in the bloodstream, where it carries the growth factors predominantly in stable complexes that contain the binding protein, either IGF-1 or IGF-2, and a third protein called the acid-labile subunit or ALS. For IGFs to reach the tissues from the bloodstream, the circulating complexes are believed to partly dissociate, possibly enhanced by limited proteolysis of IGFBP-3. The IGF-1/IGFBP-3 ratio has sometimes been used as an index of IGF bioavailability in the human circulation, but this ignores IGF-1 binding to other IGFBPs (so the ratio is affected by the concentrations of all six IGFBPs), and the fact that IGF-2, which is three times more abundant than IGF-1 in the bloodstream of adults, occupies the majority of binding sites on circulating IGFBP-3. Within tissues, IGFBP-3 can bind IGF-1 and IGF-2 released by many cell types, and block their access to the IGF-1 receptor (IGF1R), which is activated by both IGFs. IGFBP-3 also interacts with cell-surface proteins, affecting cell signaling from outside the cell or after internalization, and also enters the cell nucleus where it binds to nuclear hormone receptors and other ligands. High levels of IGFBP-3 within tumors are associated with increased cancer severity (or worse outcome) for some cancers, but decreased severity or better outcome for others.
68Ga DOTA-TATE (gallium-68 dotatate, GaTate) is used to measure tumor SSR density and whole-body bio-distribution via PET imaging. 68Ga DOTA-TATE imagery has a much higher sensitivity and resolution compared to 111In octreotide gamma camera or SPECT scans, due to intrinsic modality differences. It is commonly used to confirm the presence of paragangliomas and pheochromocytomas.
Sources: en.wikipedia.org
The main gateway to work in Australian law is a contract based on consent. A contract begins whenever an employer and employee have agreed on work for a wage, although the Australian High Court distinguishes an "employment relationship", which only begins from the start date of work, unlike the contract that starts at the time of agreement. A contract's terms include anything a reasonable person would believe is included from an employer's words or conduc. So, in Saad v TWT the Federal Court held that a spoken promise to a TV media salesperson that they would be given a lucrative sales territory was a term, even though it was not included in the written service contract. Even if a promise is not intended to be a term, representation that is misleading when made, and meant the employee foreited other opportunities, is actionable under the Competition and Consumer Act 2010 Sch 2. If an employee is told two things which conflict, the court's task is to construe the contract consistently, and tends to interpret terms against experienced commercial parties, which employers usually are, and to give preference to more specifically negotiated terms. Awards, enterprise bargains, and employer policy manuals will usually be incorporated into the contract. Under the Fair Work Act 2009 sections 124-125 employers must give each new employee a "Fair Work Information Statement" of their rights to national employment standards, awards, and their right to join a union.
== Chemistry == Chemical investigations of petroleum ether and chloroform extracts led to the isolation of β-sitosterol, ursolic acid, oleanolic acid, 3-epiursolic acid, 3-epioleanolic acid and minor triterpenoids of derivatives of ursolic acid and oleanolic acids. Chromatographic purification of the methanol extract yield two iridoid glucosides (verbenalin and hastatoside), a phenylpropanoid glycoside, verbascoside and β-sitosterol-D-glucoside. Hastatoside and verbenalin have sleep-promoting (soporific) properties. It also contains a monoterpene alcohol called verbenol. In another study, four compounds were isolated and identified as apigenin, 4'-hydroxywogonin, verbenalin, and hastatoside. Aucubin has also been found as one of the active constituents.
conserved sequence A nucleic acid or protein sequence that is highly similar or identical across many species or within a genome, indicating that it has remained relatively unchanged through a long period of evolutionary time.
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.