五肽 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 2025-11-19. 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 of compounds. Researchers at a pharmaceutical company first described it in the 1990s while screening small peptides for growth hormone releasing activity. Its chain contains five amino acid residues, two of which are non-natural building blocks, including 2-aminoisobutyric acid and a naphthylalanine derivative. The molecule was designed to act at the ghrelin receptor while avoiding several effects observed with earlier secretagogues.
At the cellular level, ipamorelin binds the growth hormone secretagogue receptor, also called the ghrelin receptor. Activation of this receptor on pituitary somatotroph cells triggers a signaling cascade that leads to release of growth hormone into circulation. Because release follows a pulsatile pattern, studies often report peak concentration and total area under the curve rather than a single time point. Selectivity for this receptor is the property most frequently discussed in comparative work.
Mass spectrometry confirms identity and reveals structural deviations that chromatography alone can miss. Positive-mode electrospray ionisation generally yields multiply charged ions whose deconvoluted mass is checked against the theoretical value. Amino acid analysis, and enzymatic digestion with subsequent fragment mapping, provide independent confirmation of sequence and of the terminal amide. Analysts take care to separate the target from deletion sequences, which may differ by one residue and therefore by only a small mass increment.
The lyophilised solid is normally held at -20 °C or colder, shielded from light and moisture. Stability in that state is measured in years, although shelf life depends on residual water content and the container seal. Once dissolved, the peptide is more fragile: aqueous solutions are commonly kept at 2-8 °C and used within days to weeks, and repeated freeze-thaw cycling is avoided. Strongly acidic or basic conditions accelerate hydrolysis, and prolonged exposure to them can strip the terminal amide.
Purity assessment for this peptide relies mainly on reversed-phase high-performance liquid chromatography. A C18 column with a water-acetonitrile gradient containing trifluoroacetic acid separates the target from truncated sequences and oxidation products. Detection near 214 nm exploits the amide backbone, while the aromatic side chains allow additional monitoring close to 280 nm. Reported purity values depend on the method, so a certificate of analysis carries weight only when gradient, column and integration parameters are given.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic pentapeptide | Growth hormone secretagogue family |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 | Contains two non-natural residues |
| Molecular formula | C38H49N9O5 | Free base form |
| Molecular weight | 711.85 g/mol | Calculated from formula |
| Primary target | GHS-R1a ghrelin receptor | Agonist activity |
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.
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.
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。
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。
In the scientific literature, ipamorelin appears mainly in preclinical studies, receptor binding assays, and reviews of growth hormone secretagogues. Authors often discuss its selectivity profile alongside limitations such as small sample sizes, short study durations, and differences between species. Some papers examine pharmacokinetics and clearance, but human data are limited and not sufficient to define general clinical effects. Regulatory discussion treats the compound as an investigational or research substance rather than an approved therapy in most jurisdictions. Open questions include oral bioavailability, long-term endocrine effects, and whether selectivity observed in animals persists in humans.
Research peptides such as ipamorelin are commonly supplied as lyophilized powder and characterized by analytical certificates. Reversed-phase high-performance liquid chromatography is used to estimate purity by ultraviolet absorbance, while mass spectrometry confirms molecular identity and detects sequence-related impurities. Counterion content, water content, and residual synthesis reagents can affect the reported mass balance. A certificate of analysis may list a purity percentage, but that number depends on the analytical method and the definition of impurity peaks. Independent verification is often recommended because research supply chains vary in quality control practices.
Storage recommendations for ipamorelin usually focus on temperature, moisture, and light. Lyophilized powder is typically held at or below minus twenty degrees Celsius in a desiccated container protected from light. Reconstituted solutions are often aliquoted and stored at minus eighty degrees Celsius to reduce repeated freeze-thaw cycles, which can promote aggregation or degradation. The optimal buffer and pH depend on the specific assay, and no single condition applies to every experimental context. Peptide stability should be assessed with time-point measurements rather than assumed from general handling rules.
Reversed-phase high-performance liquid chromatography is the standard tool for assessing purity. Detection near 214 nanometers captures the peptide backbone, and the resulting chromatogram shows the main peak alongside related impurities. Electrospray ionization mass spectrometry confirms molecular mass and supports sequence verification. Common degradation products include oxidized residues, deamidated forms, and truncated fragments, each appearing as a distinct peak or shoulder in the trace.
Quality claims for research peptides vary widely across suppliers. A certificate of analysis should list purity by chromatography, the mass found by spectrometry, and the analytical conditions used. Independent testing at a third-party laboratory is a common way to check identity and purity, because documents alone cannot confirm what is inside a vial. Purity figures describe the proportion of the target peptide among detected species, and they say nothing about biological activity or sterility.
=== Sexual dysfunction === Selegiline has been assessed for treatment of sexual dysfunction induced by antipsychotics in people with schizophrenia, but was not effective in a single small clinical study. It also did not improve sexual function in men with depression, but did improve several domains of sexual function in women with depression.
14 March – SpaceX successfully launches the Starship spacecraft, but loses the rocket upon re-entering the atmosphere. 19 March Scientists demonstrate a wireless network of 78 tiny sensors able to gather data from the brain, with potential to be scaled up to thousands of such devices. Researchers with the National Severe Storms Laboratory, Storm Prediction Center, CIWRO, and the University of Oklahoma's School of Meteorology publish a paper where they state, ">20% of supercell tornadoes may be capable of producing EF4–EF5 damage" and that "the legacy F-scale wind speed ranges may ultimately provide a better estimate of peak tornado wind speeds at 10–15 m AGL for strong–violent tornadoes and a better damage-based intensity rating for all tornadoes" and also put the general 0–5 ranking scale in question. 20 March – The removal of HIV from infected cells using CRISPR gene editing technology is reported. 26 March – A study outlines identified ecological pandemic prevention measures for policy frameworks.
== Spectroscopy and magnetism == In contrast to most organic compounds, many inorganic compounds are magnetic and/or colored. These properties provide information on the bonding and structure. The magnetism of inorganic compounds can be complex. For example, most copper(II) compounds are paramagnetic but CuII2(OAc)4(H2O)2 is almost diamagnetic below room temperature. The explanation is due to magnetic coupling between pairs of Cu(II) sites in the acetate.
These kingdoms were defined as "the viceroyalties of New Spain (Mexico), Peru, New Granada, and Buenos Aires, and the independent captaincies general of the island of Cuba, Puerto Rico, Guatemala, Chile, Province of Venezuela, and the Philippines." This plan was criticized for providing unequal representation to Spanish America; nevertheless, throughout the end of 1808 and early 1809, the regional capitals elected candidates, whose names were forwarded to the capitals of the viceroyalties or captaincies general. Several important and large cities were left without direct representation in the Supreme Junta. In particular Quito and Chuquisaca, which saw themselves as the capitals of kingdoms, resented being subsumed in the larger Viceroyalty of Peru and Viceroyalty of the Río de la Plata respectively. This unrest led to the establishment of juntas in these cities in 1809, which were eventually quashed by the authorities within the year. An unsuccessful attempt at establishing a junta in New Spain was also stopped.
Sources: en.wikipedia.org
==== MeSH E05.601.495 – immunoassay ==== MeSH E05.601.495.320 – immunoblotting MeSH E05.601.495.320.200 – blotting, western MeSH E05.601.495.350 – immunoenzyme techniques MeSH E05.601.495.350.170 – enzyme-linked immunosorbent assay MeSH E05.601.495.350.180 – enzyme multiplied immunoassay technique MeSH E05.601.495.380 – immunosorbent techniques MeSH E05.601.495.380.360 – enzyme-linked immunosorbent assay MeSH E05.601.495.380.810 – radioallergosorbent test MeSH E05.601.495.380.825 – radioimmunoprecipitation assay MeSH E05.601.495.380.830 – radioimmunosorbent test MeSH E05.601.495.639 – radioimmunoassay MeSH E05.601.495.639.405 – immunoradiometric assay MeSH E05.601.495.639.810 – radioallergosorbent test MeSH E05.601.495.639.825 – radioimmunoprecipitation assay MeSH E05.601.495.639.830 – radioimmunosorbent test
== Mechanism == Most of the energy of the primary ions is dissipated into the near-surface region of the solid by a series of binary collisions. This results in ejection (sputtering) of so-called "secondary" particles such as electrons, atoms, molecules, and ions from the surface. In SIMS, it is these secondary ions which are detected and analyzed by a mass spectrometer to produce a mass spectrum of a surface for a detailed chemical analysis of the surface or the solid. The secondary-ion current is given by
==== Actions ==== Compound 22 is a low-potency antagonist of the trace amine-associated receptor 1 (TAAR1). It has shown significant inhibition of TAAR1 signaling at a concentration of 100 μM in vitro. The drug's IC50Tooltip half-maximal inhibitory concentration value for TAAR1 antagonism is unknown but is greater than 100 μM. Compound 22 was also screened for off-target activity at 47 targets at a concentration of 10 μM. The screened targets included monoamine receptors, monoamine transporters, histamine receptors, muscarinic acetylcholine receptors, glutamate receptors, GABA receptors, opioid receptors, and sigma receptors. There were five hits (>50% binding inhibition), which included the serotonin transporter (SERT), dopamine transporter (DAT), and norepinephrine transporter (NET), as well as the sigma σ1 and σ2 receptors. Its affinities (Ki) were 1,800 nM for the SERT, 1,053 nM for the DAT, 1,902 nM for the NET, 276 nM for the sigma σ1 receptor, and 412 nM for the sigma σ2 receptor. Although compound 22 bound with significant affinity to the DAT, it did not inhibit dopamine reuptake and did not interfere with cocaine-induced dopamine reuptake inhibition at concentrations of up to 100 μM.
Sources: en.wikipedia.org
It is a synthetic pentapeptide in the growth hormone secretagogue family. The chain contains five residues, two of which are non-natural amino acids.
It acts as an agonist at the growth hormone secretagogue receptor, also known as the ghrelin receptor. Binding at pituitary somatotroph cells promotes growth hormone release.
Early studies report weaker effects on cortisol, prolactin, and appetite than compounds such as GHRP-6. The size of that difference in humans is not firmly established.
Results are most often expressed as a percentage of total peak area from a reversed-phase separation. That figure reflects the detection wavelength, gradient and integration choices used by the laboratory. Two valid certificates can therefore quote different values for the same material without either being incorrect.