The short version of freeze-thaw fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-07-31. 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 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.
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.
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.
| 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 |
Long-term storage of the dry powder is typically at minus twenty degrees Celsius or lower, protected from light and moisture. Solutions are commonly kept frozen and thawed only once, because repeated freeze-thaw cycles can promote aggregation and loss of measurable peptide content. Buffers near neutral pH are preferred over strongly acidic or strongly basic conditions. Shipping at ambient temperature is acceptable for short periods when the powder remains sealed and desiccated.
Identity and purity are assessed by complementary methods rather than a single test. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and reports a percentage purity. Mass spectrometry, most often with electrospray ionization, confirms the expected molecular mass and detects sequence-related variants. Amino acid analysis can verify composition, while water content and residual counterion measurements support the mass balance of a batch. Stability studies under accelerated conditions are used to estimate shelf life, though such estimates carry uncertainty for long-term storage.
Material supplied for research use is normally a white to off-white lyophilized powder. The solid is hygroscopic and is handled in a low-humidity environment to limit water uptake. Bulk quantities are frequently shipped in sealed vials under inert gas. Once reconstituted in water or a neutral buffer, the solution is less stable than the dry powder and is usually divided into single-use aliquots.
Most published work on ipamorelin comes from rodent studies and small early-phase human trials. Subcutaneous and intravenous routes have been used, while oral delivery is limited by poor absorption and rapid breakdown in the gut. The reported plasma half-life is short, on the order of two hours, and varies with species and assay method. Whether chronic use produces meaningful clinical benefit remains unresolved, and long-term safety data in humans are sparse. No major regulatory agency has approved the compound as a therapeutic drug.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue family. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, incorporating two non-natural residues that resist enzymatic breakdown. Researchers at Novo Nordisk described the compound in the 1990s while searching for agents that release growth hormone with fewer side effects than earlier secretagogues. The molecule acts as an agonist at the ghrelin receptor, also called GHS-R1a, which is expressed in the pituitary and in several peripheral tissues.
Selectivity distinguishes ipamorelin from first-generation secretagogues such as GHRP-6. At doses that reliably raise growth hormone, it shows little stimulation of adrenocorticotropic hormone or cortisol release in animal models, and it does not markedly raise prolactin or appetite. Binding at GHS-R1a on pituitary somatotrophs triggers calcium influx and pulsatile growth hormone secretion. Because the compound mimics the natural ghrelin signal, the release pattern tends to follow the body's own rhythm rather than producing a sustained elevation.
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.
GLD-2 (which stands for Germ Line Development 2) is an enzyme which in humans is encoded by the gene TENT2. More specifically, it is a cytoplasmic poly(A) polymerase (cytoPAPs) which adds successive AMP monomers to the 3’ end of specific RNAs, forming a poly(A) tail, which is a process known as polyadenylation. For RNA specificity, GLD-2 associates with an RNA-binding protein, typically a GLD-3, to form a heterodimer that acts as a cytoplasmic PAP. This protein has an enzymatic function and belongs to a family (DNA polymerase type-B-like family) which includes several similar enzymes such as GLD-1, GLD-3 and GLD-4. This family of cytoplasmic PAPs has been described in several different species including Homo sapiens, Caenorhabditis elegans, Xenopus, Mus musculus and Drosophila. Moreover, as it is a cytoplasmtaic PAP it differs from nuclear PAPs in some aspects. While nuclear PAPs contain a catalytic domain and an RNA-binding domain, GLD-2 family members have only a catalytic domain.
Lutetium occurs on the Earth in two isotopes: lutetium-175 and lutetium-176. Out of these two, only the former is stable, making the element monoisotopic. The latter one, lutetium-176, decays via beta decay with a half-life of 3.70×1010 years; it makes up about 2.6% of natural lutetium. To date, 40 synthetic radioisotopes of the element have been characterized, ranging in mass number from 149 to 188; the most stable such isotopes are lutetium-174 with a half-life of 3.31 years, and lutetium-173 with a half-life of 1.37 years. All of the remaining radioactive isotopes have half-lives that are less than 9 days, and the majority of these have half-lives that are less than half an hour. Isotopes lighter than the stable lutetium-175 decay via electron capture (to produce isotopes of ytterbium), with some alpha and positron emission; the heavier isotopes decay primarily via beta decay, producing hafnium isotopes. Experiments at the Facility for Rare Isotope Beams have reported lutetium-190 in fragments of platinum-198 colliding with a carbon target. The element also has 43 known nuclear isomers, of which the most stable of them are lutetium-177m3, with a half-life of 160.4 days, and lutetium-174m with a half-life of 142 days; longer than the ground states of all lutetium isotopes except 173-176.
5 October – Biologists report studies confirming the age of human footprints found in the state of New Mexico in the United States to be "up to 23,000 years old", the earliest found traces of people in North America. 10 October – Gene-edited chickens with partial resistance to bird flu are developed at the University of Edinburgh's Roslin Institute. 11 October The first known afterglow of a collision between two exoplanets is captured by astronomers, who observe the event around a Sun-like star located 1,800 light years away. The recovered capsule from the OSIRIS-REx sample-return mission, that sampled the asteroid 101955 Bennu, is opened to reveal a "first look" at the asteroid sample contents. 12 October An expert elicitation study reports potential scenarios of civil unrest in the UK in the coming decades, due to food shortages caused by extreme weather. A study highlights the exponential growth of satellite constellations in Earth orbit, which is "creating serious safety and long-term sustainability challenges" and requires urgent action by the International Telecommunication Union. A review summarizes the research on the transition from unconsciousness to consciousness in humans, integrating new neuroscientific findings about the content and structure of infant consciousness. A study reports transient windows of decision reactivity to external stimuli during sleep and signatures of conscious processing in lucid REM sleep.
Sources: en.wikipedia.org
==== Australia and New Zealand ==== Australia and New Zealand published nutrient reference values including guidelines for dietary vitamin D intake in 2006. About a third of Australians have vitamin D deficiency.
=== Latin America === In 2021, Gustavo Gorriti, journalist and founder of corruption-focused IDL-Reporteros news media, wrote a sharply critical editorial in the Washington Post on the impact of 50 years of the war on drugs on Latin America. He described the flow of drugs to the US as an "unstoppable industry" that triggered an economic revolution throughout the region, where the illegal drug trade with its high profit margins far exceeded the potential of legitimate businesses. Corruption among politicians and anti-drug forces soared, even as those in charge were "cultivating close relationships with U.S. enforcement and intelligence agencies." An underclass of poor farmers became economic hostages, depending on drug crops for their survival. The big winners were "the systems built to wage a fight that they soon realized would have no end. ... [The war on drugs] became a source for endless resources, inflated budgets, contracts, purchase orders, power, influence – new economies battling drug trafficking but also dependent on it." At a meeting in Guatemala in 2012, three former presidents from Guatemala, Mexico and Colombia said that the war on drugs had failed and that they would propose a discussion on alternatives, including decriminalization, at the Summit of the Americas in April of that year. Guatemalan President Otto Pérez Molina said that the war on drugs was exacting too high a price on the lives of Central Americans and that it was time to "end the taboo on discussing decriminalization".
=== Health economics and cost effects === Compared to insulin therapy in patients with type 2 diabetes requiring treatment, GLP-1 RAs may be more cost-effective. In a recent observation of a cohort study using Taiwan's National Health Isurance Research Database, GLP-1 RA therapy was associated with improved clinical outcomes. This includes reductions in mortality and hospitalized hypoglycemia relative to insulin. From an economic perspective, GLP-1 RAs were associated with higher direct drug costs but demonstrated value when evaluated against clinical outcomes. The cost per case prevented was approximately $54,851 for all-cause mortality and $29,115 for hospitalized hypoglycemia from the perspective of a third-party payer. But GLP-1 RA use was associated with net cost savings and reflected a downward movement of healthcare use. Studies found that GLP-1 RAs are cost-effective for only some patients. These population groups are limited to long-term cardiovascular and metabolic benefits. Overall, evidence suggests that though these receptor agonists have higher upfront costs, their ability to reduce adverse clinical events may make them a more cost-effective therapy option.
Medical uses include treatment of severe anxiety. Despite certain side effects and the emergence of alternative products (e.g., pregabalin), benzodiazepine medication remains an effective way of reducing problematic symptoms, and is typically deemed effective by patients and medical professionals. Similarly to other intermediate-acting depressants, it may be used as hypnotic medication, though prescribing for insomnia is generally limited to a maximum of four weeks due to dependence risks and limited long-term efficacy or in order to mitigate withdrawal effects of alcohol consumption.
Sources: en.wikipedia.org
== Connections with Morocco == Belgian Justice Minister Vincent Van Quickenborne described Morocco as a nation known for interfering in the EU. He said the investigation was focusing on multiple subjects, including the EU-Morocco trade agreements and the fisheries agreement. A report by the Financial Times revealed that the Pier Antonio Panzeri received bribes, gifts and luxury hotel stays from the Moroccan government. The former Italian MEP had ties with Moroccan officials since he was the head of the European Parliament's EU-Maghreb delegation. Records revealed that during his time in the parliament Panzeri supported decisions favoring the Moroccan government. He had raised a request to the European Commission for allocation of more funds for Morocco, and also voted in favor of Morocco's trade agreement with the EU and the fisheries agreement. Panzeri received secret payments from Morocco's ambassador to Poland Abderrahim Atmoun through the NGOs. Panzeri and Atmoun worked together as co-chairs of the Morocco-EU joint parliamentary committee. Panzeri admitted Atmoun provided financial help for his 2014 electoral campaign, including covering a €50,000 cost of a party in Milan. In 2014, Moroccan King Mohammed VI awarded Panzeri with the third class Order of Ouissam Alaouite for his services to Rabat. Atmoun received the same decoration at the same event. Belgium has drafted a request for a European arrest warrant for Atmoun who is believed to have received funds from Moroccan officials to bribe members of European Parliament to favour Morocco.
=== Flexural anatomy === Flexural anatomy is frequently described as a difficult area. It is simplified when each flexure is considered as being centered on a mesenteric contiguity. The ileocaecal flexure arises at the point where the ileum is continuous with the caecum around the ileocaecal mesenteric flexure. Similarly, the hepatic flexure is formed between the right mesocolon and transverse mesocolon at the mesenteric confluence. The colonic component of the hepatic flexure is draped around this mesenteric confluence. Furthermore, the splenic flexure is formed by the mesenteric confluence between the transverse and left mesocolon. The colonic component of the splenic flexure occurs lateral to the mesenteric confluence. At every flexure, a continuous peritoneal fold lies outside the colonic/mesocolic complex tethering this to the posterior abdominal wall.
==== Homochiral MOFs with interesting functionalities and reagent-accessible channels ==== Homochiral MOFs have been made by Lin and coworkers using 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) and 1,1′-bi-2,2′-naphthol (BINOL) as chiral ligands. These ligands can coordinate with catalytically active metal sites to enhance the enantioselectivity. A variety of linking groups such as pyridine, phosphonic acid, and carboxylic acid can be selectively introduced to the 3,3′, 4,4′, and the 6,6′ positions of the 1,1'-binaphthyl moiety. Moreover, by changing the length of the linker ligands the porosity and framework structure of the MOF can be selectively tuned.
In a broad academic audience, the concept of the evolution of the genetic code from its original ambiguous form to a well-defined ("frozen") code with the repertoire of 20 (+2) canonical amino acids is widely accepted. However, there are different opinions, concepts, approaches and ideas regarding how to best reproduce this process experimentally. Even models are proposed that predict "entry points" for synthetic amino acid invasion of the genetic code. Since 2001, 40 non-natural amino acids have been added into proteins by creating a unique codon (recoding) and a corresponding transfer-RNA:aminoacyl – tRNA-synthetase pair to encode it with diverse physicochemical and biological properties in order to be used as a tool to exploring protein structure and function or to create novel or enhanced proteins. H. Murakami and M. Sisido extended some codons to have four and five bases. Steven A. Benner constructed a functional 65th (in vivo) codon. In 2015 N. Budisa, D. Söll and co-workers reported the full substitution of all 20,899 tryptophan residues (UGG codons) with unnatural thienopyrrole-alanine in the genetic code of the bacterium E. coli. In 2016 the first stable semisynthetic organism was created. It was a (single cell) bacterium with two synthetic bases (called X and Y). The bases survived cell division. In 2017, researchers in South Korea reported that they had engineered a mouse with an extended genetic code that can produce proteins with unnatural amino acids. In May 2019, researchers reported the creation of a new "Syn61" strain of the E. coli bacteria.
Some contact problems can be solved with the method of dimensionality reduction (MDR). In this method, the initial three-dimensional system is replaced with a contact of a body with a linear elastic or viscoelastic foundation (see fig.). The properties of one-dimensional systems coincide exactly with those of the original three-dimensional system, if the form of the bodies is modified and the elements of the foundation are defined according to the rules of the MDR. MDR is based on the solution to axisymmetric contact problems first obtained by Ludwig Föppl (1941) and Gerhard Schubert (1942) However, for exact analytical results, it is required that the contact problem is axisymmetric and the contacts are compact.
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.
Purity is commonly estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection. Mass spectrometry is used to confirm identity and to detect sequence-related impurities. Reported percentages depend on the method and the impurity threshold used.