incretin 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.
Last reviewed on 2026-01-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semaglutide is a synthetic peptide analog of human glucagon-like peptide-1, developed by Novo Nordisk and first approved in 2017 for type 2 diabetes. It belongs to the incretin mimetic class, a group of agents that reproduce the glucose-dependent actions of endogenous GLP-1. The molecule was engineered to resist degradation by dipeptidyl peptidase-4 and to bind serum albumin, extending its half-life from minutes to roughly one week. Approval for chronic weight management followed in 2021, based on large cardiovascular and obesity outcome trials.
GLP-1 receptors are expressed on pancreatic beta cells, in the gut, and in several brain regions. Receptor activation raises cyclic AMP, enhances glucose-dependent insulin secretion, and suppresses glucagon release when blood glucose is high. Effects on gastric emptying and on hypothalamic appetite circuits reduce energy intake. Because insulin release remains glucose-dependent, the risk of hypoglycemia is low when the drug is used alone. The precise contribution of each pathway to body weight change in humans remains an area of active investigation.
Clinical studies of semaglutide generally measure glycated hemoglobin, fasting plasma glucose, body weight, and composite cardiovascular endpoints. The SUSTAIN program enrolled adults with type 2 diabetes, while the STEP program focused on obesity without diabetes. Administration follows a stepwise escalation schedule designed to limit gastrointestinal effects during the first weeks. Reported outcomes include mean percentage weight change, the proportion of participants reaching defined weight-loss thresholds, and rates of nausea, vomiting, and diarrhea. Long-term data on durability after treatment stops are still limited and remain a topic of ongoing research.
Receptor activation occurs at GLP-1 receptors distributed across pancreatic islets, the hypothalamus, and the gastrointestinal tract. Binding triggers G protein signaling that raises cyclic AMP and enhances glucose-dependent insulin release. Because the effect depends on prevailing glucose levels, insulin secretion does not rise when blood sugar is already low. Signaling in the brain and gut also influences appetite and gastric emptying, which is why the compound appears in both metabolic and weight-related research literature.
Development began in the early 2010s with the goal of extending GLP-1 activity beyond the brief window achieved by native peptide infusion. The earliest approved formulation was a subcutaneous injection given once weekly. A later oral tablet pairs the peptide with an absorption enhancer, sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, usually shortened to SNAC. That carrier lowers local pH and helps the peptide cross gastric tissue. Both routes deliver the same active molecule.
Semaglutide is a synthetic peptide analog of human glucagon-like peptide-1, a gut hormone released after meals. Its backbone retains the GLP-1 sequence but incorporates two substitutions that slow enzymatic breakdown by dipeptidyl peptidase-4. A short polyethylene glycol linker and a C18 fatty diacid are attached to the peptide chain, allowing the molecule to bind serum albumin and remain in circulation far longer than the native hormone. The result is a circulating half-life measured in days rather than the minutes typical of endogenous GLP-1.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C187H291N45O59 | Peptide backbone with a C18 fatty diacid side chain |
| Molecular weight | Approximately 4113 Da | Consistent with a 31-residue peptide plus linker |
| Appearance | White to off-white powder | Lyophilized solid; hygroscopic if left open |
| Solubility class | Sparingly soluble to soluble in water | Varies with pH and ionic strength |
| Typical analytical method | Reversed-phase HPLC with UV detection | Often paired with mass spectrometry for identity |
Material described as research-grade is not necessarily manufactured to pharmaceutical standards, and purity figures depend on the method used to obtain them. A certificate of analysis states the measured purity, the analytical technique, and the batch identifier, but the underlying data are not always included. Independent testing by a second laboratory is a common way to confirm identity and purity. Uncertainties remain about how storage history affects long-term stability, and about how well results from one laboratory transfer to another. Documentation of handling conditions supports comparison between batches.
Peptides are sensitive to temperature, light, oxygen, and repeated freeze-thaw cycles. Semaglutide in dry form is generally held at refrigerated temperatures, while reconstituted solutions require a defined short-term storage window. Vials should be kept in secondary packaging to limit photodegradation, and exposure to alkaline conditions is avoided because it accelerates chemical degradation. Adsorption to glass and some plastics can reduce the measured concentration of dilute solutions, so low-binding polypropylene containers are preferred for analytical work. Each transfer step introduces a small risk of contamination, and closed handling practices reduce that risk.
Routine characterisation of the peptide relies on reversed-phase high-performance liquid chromatography, often paired with ultraviolet detection near 214 nanometres. Related substances such as deamidated, oxidised, and truncated sequences elute at characteristic positions and are quantified by area percentage. Electrospray ionisation mass spectrometry confirms the molecular mass and can resolve some closely related variants. Peptide mapping after enzymatic digestion provides sequence-level verification and is useful when a full identity profile is required. Method parameters such as column chemistry, gradient, and mobile-phase pH influence the separation and must be reported alongside results.
Quantification and purity assessment rely on separation methods coupled to optical or mass detection. Reversed-phase high-performance liquid chromatography resolves the intact peptide from related impurities and is the standard assay technique. Size-exclusion chromatography measures aggregates, while ion-exchange chromatography separates charge variants produced by deamidation. Mass spectrometry confirms identity and detects mass shifts of a few daltons. In biological matrices, liquid chromatography with tandem mass spectrometry is often used because immunoassays can cross-react with endogenous GLP-1 or with circulating fragments.
As a peptide, semaglutide is sensitive to conditions that break amide bonds or modify side chains. Deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation are the main degradation routes described in published stability work. Rate depends strongly on pH, buffer species, ionic strength, temperature and exposure to light. Formulators therefore choose a defined solution pH and often add excipients such as phosphate buffer, propylene glycol and phenol, each of which plays a separate role in pH control, tonicity or preservation.
=== For acute coronary syndrome === The combination of a P2Y12 inhibitor and aspirin, called dual antiplatelet treatment, remains the first-line treatment for acute coronary syndrome. A 2019 randomized trial suggested that prasugrel is superior to ticagrelor.
== Etymology == Moscow's name is thought to be derived from that of the Moskva River. Multiple theories have been proposed for the origin of this river's name. The linguistically best-grounded and most widely accepted theory is that the name comes from the Proto-Balto-Slavic root *mŭzg-/muzg-, from the Proto-Indo-European *meu- "wet"; thus, the name Moskva might signify a river at a wetland or marsh. The name's cognates include the following:
== GST-tags and the GST pull-down assay == GST can be added to a protein of interest to purify it from solution in a process known as a pull-down assay. This is accomplished by inserting the GST DNA coding sequence next to that which codes for the protein of interest. Thus, after transcription and translation, the GST protein and the protein of interest will be expressed together as a fusion protein. Because the GST protein has a strong binding affinity for GSH, beads coated with the compound can be added to the protein mixture; as a result, the protein of interest attached to the GST will stick to the beads, isolating the protein from the rest of those in solution. The beads are recovered and washed with free GSH to detach the protein of interest from the beads, resulting in a purified protein. This technique can be used to elucidate direct protein–protein interactions. A drawback of this assay is that the protein of interest is attached to GST, altering its native state. A GST-tag is often used to separate and purify proteins that contain the GST-fusion protein. The tag is 220 amino acids (roughly 26 kDa) in size, which, compared to tags such as the Myc-tag or the FLAG-tag, is quite large. It can be fused to either the N-terminus or C-terminus of a protein. In addition to functioning as a purification tag, GST acts as a chaperone for the attached protein, promoting its correct folding, as well as preventing it from becoming aggregated in inclusion bodies when expressed in bacteria.
Prolyl endopeptidase is a large cytosolic enzyme that belongs to a distinct class of serine peptidases. It was first described in the cytosol of rabbit brain as an oligopeptidase, which degrades the nonapeptide bradykinin at the Pro-Phe bond. The enzyme is involved in the maturation and degradation of peptide hormones and neuropeptides such as alpha-melanocyte-stimulating hormone, luteinizing hormone-releasing hormone (LH-RH), thyrotropin-releasing hormone, angiotensin, neurotensin, oxytocin, substance P and vasopressin. PREP cleaves peptide bonds at the C-terminal side of proline residues. Its activity is confined to action on oligopeptides of less than 10 kD and it has an absolute requirement for the trans-configuration of the peptide bond preceding proline. Prolyl endopeptidases are involved in the maturation and degradation of peptide hormones and neuropeptides.
Sources: en.wikipedia.org
Eventually, the 4th Division commander discovered that the chief of the general staff had ordered a general retreat from the capital, whereupon he attempted to countermand the order to little success.
== As a target == Elongation factors are targets for the toxins of some pathogens. For instance, Corynebacterium diphtheriae produces diphtheria toxin, which alters protein function in the host by inactivating elongation factor (EF-2). This results in the pathology and symptoms associated with diphtheria. Likewise, Pseudomonas aeruginosa exotoxin A inactivates EF-2.
After the fall of Tripoli in August 2011, only a few towns in western Libya such as Bani Walid, Sebha, and Sirte remained Gaddafist strongholds. Gaddafi was reportedly planning to catch up with his Sebha commander Ali Kanna's Tuareg forces and seek asylum in Burkina Faso. Instead, Gaddafi retreated to his hometown of Sirte, where he convened a meeting with his son Mutassim and intelligence chief Abdullah Senussi and learned that his youngest son Khamis had been killed by a NATO airstrike on 29 August. In the weeks that followed, Gaddafi continued to broadcast defiant audio messages through Syria-based Arrai TV. On 10 September, General Massoud Abdel Hafiz announced the formation of the Republic of Fezzan in Sebha, where Gaddafi would be president for life. Sebha fell on 22 September. Surrounding himself with bodyguards and a small entourage, including Mutassim, security chief Mansour Dhao, and defense minister Abu-Bakr Yunis Jabr, Gaddafi continually changed residences to escape NATO and NTC shelling, devoting his days to prayer and reading the Qur'an. On 20 October, Gaddafi recorded a farewell audio message for his family, later publicized by Al-Hadath, and then broke out of Sirte's District 2 in a joint civilian-military convoy. According to Dhao, it was a "suicide mission" as Gaddafi wanted to die in the Jarref Valley, close to where he was born. At around 08:30, NATO bombers attacked, destroying at least 14 vehicles and killing at least 53 people.
In the 1930s-1950s, the first protein structures were solved by protein crystallography. These early structures suggested that a fixed three-dimensional structure might be generally required to mediate biological functions of proteins. These publications solidified the central dogma of molecular biology in that the amino acid sequence of a protein determines its structure which, in turn, determines its function. In 1950, Fred Karush at the Neurological Institute of New York described the "configurational adaptability" found in serum albumins contradicting this assumption. Karush was convinced that proteins have more than one configuration at the same energy level and can choose one when binding to other substrates. In the 1960s, Levinthal's paradox suggested that the systematic conformational search of a long polypeptide is unlikely to yield a single folded protein structure on biologically relevant timescales (i.e. microseconds to minutes). Curiously, for many (small) proteins or protein domains, relatively rapid and efficient refolding can be observed in vitro. As stated in Anfinsen's Dogma from 1973, the fixed 3D structure of these proteins is uniquely encoded in its primary structure (the amino acid sequence), is kinetically accessible and stable under a range of (near) physiological conditions, and can therefore be considered as the native state of such "ordered" proteins.
– the particles are not coated or surface modified. In July 2025, the Scientific Committee on Consumer Safety (SCCS) adopted its fourth opinion (Submission IV), concluding that nano‑hydroxyapatite is safe at concentrations up to 29.5% in toothpaste and up to 10% in mouthwash, under defined particle morphology constraints.
Sources: en.wikipedia.org
== Digestibility == Hemp protein, when untreated, is more digestible compared to soy protein. Heat pre-treatment at temperatures above 80 °C may improve the digestibility of both hemp and soy protein, but in untreated (unheated) form hemp protein is more readily digested than the soy one. Dehulled hemp seeds (also known as hemp nuts, hemp kernels or hemp hearts) have a protein digestibility corrected amino acid score (PDCAAS) of 0.66, with lysine being the limiting amino acid (digestibility of 92.1%). With its gluten content as low as 4.78 ppm, hemp is attracting attention as a gluten-free (<20 ppm) food material. Hemp protein is sold in bulk as a powder, in various forms, such as hempseed meal, hemp protein concentrates, and hemp protein isolates. It generally has greenish hue due to the natural pigments in the hemp plant, but the color can vary depending on the specific processing methods used. Unflavored hemp protein powder is commonly available, that is, no additional flavoring is added to the hemp protein, which is usually described as earthy or nutty.
== Background == Crude oil contains sulfur in its composition, with the latter being the most abundant element after carbon and hydrogen. Depending on its source, the amount of sulfur present in crude oil can range from 0.05 to 10%. Accordingly, the oil can be classified as sweet or sour if the sulfur concentration is below or above 0.5%, respectively. The combustion of crude oil releases sulfur oxides (SOx) to the atmosphere, which are harmful to public health and contribute to serious environmental effects such as air pollution and acid rains. In addition, the sulfur content in crude oil is a major problem for refineries, as it promotes the corrosion of the equipment and the poisoning of the noble metal catalysts. The levels of sulfur in any oil field are too high for the fossil fuels derived from it (such as gasoline, diesel, or jet fuel ) to be used in combustion engines without pre-treatment to remove organosulfur compounds. The reduction of the concentration of sulfur in crude oil becomes necessary to mitigate one of the leading sources of the harmful health and environmental effects caused by its combustion. In this sense, the European Union has taken steps to decrease the sulfur content in diesel below 10 ppm, while the US has made efforts to restrict the sulfur content in diesel and gasoline to a maximum of 15 ppm. The reduction of sulfur compounds in oil fuels can be achieved by a process named desulfurization.
=== Artwork === In 2017, Carrey revealed that he had been painting for the past six years. In 2011, he exhibited the painting Nothing to See Here in an art show in Palm Springs at the Heather James Fine Art Gallery. In 2017, Carrey released a six-minute documentary entitled I Needed Color, which showed him working in his studio. In 2018, Carrey's artwork was displayed at the Outsider Art Fair, leading to discussion as to whether or not a Hollywood actor could qualify as an outsider artist.
=== Tyrosine-based products === Tanning accelerators—lotions or pills that usually contain the amino acid tyrosine—claim that they stimulate and increase melanin formation, thereby accelerating the tanning process. These are used in conjunction with UV exposure. At this time, there is no scientific data available to support these claims.
Tin-121m (121mSn) is a nuclear isomer of tin with a half-life of 43.9 years, making it technically a medium-lived fission product. In a normal thermal reactor, it has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce it at higher yields. For example, its yield from uranium-235 is 0.0007% per thermal fission and 0.002% per fast fission.
Sources: en.wikipedia.org
It is given either as a once-weekly subcutaneous injection or as an oral tablet taken once daily. The two forms use different absorption strategies, so they are not interchangeable on a milligram-for-milligram basis.
Structural modifications, including a fatty acid side chain and non-natural amino acid substitutions, slow enzymatic breakdown and promote albumin binding. These changes support once-weekly dosing rather than twice-daily administration.
The pathways involving insulin, glucagon, gastric emptying, and appetite signaling are well described. How much each pathway contributes to weight reduction in a given person is not fully established.
Native GLP-1 is degraded within minutes by circulating enzymes. The synthetic version carries substitutions at positions that block enzymatic cleavage, plus a fatty acid side chain that promotes albumin binding. These two changes together extend circulation time from minutes to roughly a week.