This is a working overview of Guanidinium group, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-11-05. Anything still debated is marked as such rather than presented as settled.
Commercial creatine products appear in several forms, including monohydrate, hydrochloride, citrate, nitrate, and ethyl ester. Creatine monohydrate is the most studied form and serves as a reference material in comparative research. Different forms vary in solubility, pH, and water content, but they share creatine as the active moiety after dissolution. Claims that one form is uniformly superior remain debated, and study designs often differ in population, exercise protocol, and outcome measures. Purity and hydration state are central to interpreting product labels.
Creatine monohydrate is the hydrated form of creatine, a nitrogen-containing organic acid involved in cellular energy transfer. Its molecular formula is C4H11N3O3, and it consists of creatine plus one water molecule in the crystal lattice. The anhydrous base, creatine, has the formula C4H9N3O2. The compound appears as a white, odorless, crystalline powder and is classified as a guanidine derivative. It is distinct from creatinine, a breakdown product measured in clinical chemistry.
Commercial creatine monohydrate is produced mainly by chemical synthesis rather than extraction from animal tissue. Suppliers provide a certificate of analysis listing assay, water content, and impurity limits, and some products undergo third-party testing. Verification of identity can use infrared or Raman spectroscopy alongside chromatographic methods. Storage recommendations generally call for a cool, dry place and a tightly closed container to limit moisture uptake. Open questions include how packaging, flavoring agents, and long-term storage affect the stability of finished products.
Dry creatine monohydrate is generally stable when kept sealed and protected from heat and moisture. In solution, however, creatine undergoes a slow cyclization to creatinine, a related compound with no role in phosphocreatine storage. The rate of this conversion increases with temperature and is influenced by pH. Because creatinine is a common impurity in liquid or poorly stored products, analytical testing often measures both compounds. The crystalline monohydrate is less prone to degradation than aqueous preparations, though caking can occur if moisture enters the container.
Laboratory analysis of creatine monohydrate typically uses high-performance liquid chromatography to separate creatine from creatinine and other impurities. Detection may be ultraviolet, refractive index, or mass spectrometric, depending on the laboratory's equipment and the required sensitivity. Nuclear magnetic resonance spectroscopy can quantify the main component and identify related substances. Water content is measured by Karl Fischer titration, which is important because the monohydrate has a defined theoretical hydration level. Heavy metals, residual solvents, and microbial limits are also checked in quality control programs.
| Property | Value | Notes |
|---|---|---|
| Chemical formula (monohydrate) | C4H11N3O3 | Includes one water molecule per creatine unit. |
| Molecular weight | 149.15 g/mol | Calculated for the monohydrate; anhydrous creatine is 131.13 g/mol. |
| Appearance | White crystalline powder | Odorless; particle size can vary by manufacturing. |
| CAS Registry Number | 6020-87-7 | Identifies creatine monohydrate; creatine base is 57-00-1. |
| Common synonyms | Creatine hydrate; methylguanidoacetic acid monohydrate | Naming varies by registry and supplier. |
In aqueous solution, creatine monohydrate exists mainly as a zwitterion, carrying both a positive guanidinium charge and a negative carboxylate charge. This charge separation raises water solubility relative to many neutral organic solids and helps explain its behavior in analytical separations. The monohydrate can lose its water of crystallization under sustained heat or low humidity, converting toward anhydrous creatine. Such transitions matter for mass balance calculations because the hydrate contributes water mass that is not part of the active creatine molecule.
The term creatine monohydrate is often shortened to creatine in casual usage, though other creatine forms exist, including citrate, nitrate, and hydrochloride salts. These alternative forms differ in solubility, pH behavior, and the amount of creatine delivered per unit mass. Regulatory categories vary by country: some jurisdictions treat it as a food ingredient, while others place it under supplement or drug frameworks depending on claims and presentation. Standard reference texts list it as a naturally occurring nitrogenous organic acid rather than a vitamin or mineral.
Creatine monohydrate is a crystalline organic compound formed from creatine and water in a one-to-one ratio. It belongs to the guanidino family and contains a methylated guanidine group attached to an acetate-like chain. The solid is commonly described as a white, odorless powder with a mildly bitter taste. Its molecular formula is C4H11N3O3·H2O, and the hydrated form is the most widely traded grade. The compound occurs naturally in vertebrate muscle and brain tissue, where it participates in rapid energy buffering.
Creatine monohydrate is a crystalline compound formed when one molecule of creatine associates with one molecule of water in the solid lattice. Its molecular formula is C4H11N3O3, and its molar mass is about 149.15 grams per mole. The material appears as a white, odorless powder that dissolves sparingly in water at room temperature. The monohydrate designation distinguishes it from anhydrous creatine, which lacks the bound water and has a lower molar mass. This hydrate is the most common commercial form of creatine used in nutritional and research settings.
Creatine is synthesized endogenously in humans, mainly in the liver, kidney, and pancreas, from the amino acids arginine, glycine, and methionine. Skeletal muscle stores much of the body's creatine, where it participates in the phosphocreatine system that buffers adenosine triphosphate during short, intense contractions. Dietary sources include meat and fish, so omnivorous diets provide additional creatine beyond endogenous production. Supplemental creatine monohydrate supplies the same molecule found in food and tissues, not a distinct drug or hormone. Research interest centers on its role in cellular energy transfer and its effects on muscle and other tissues.
Stability studies examine how creatine monohydrate changes under controlled temperature and humidity. The solid is generally stable when kept dry, but moisture can promote hydrolysis to creatinine, especially in solution or at elevated temperatures. Color, odor, and assay values are monitored over time to detect degradation. Because degradation pathways depend on storage conditions, shelf-life claims should specify the tested packaging, temperature, and humidity. Open questions remain about the long-term behavior of different crystal habits and particle sizes.
Regulatory treatment of creatine monohydrate varies by country and intended use. In some jurisdictions it is sold as a dietary supplement, while in others it may be treated as a food ingredient or a pharmaceutical raw material. Pharmacopeial monographs, where available, define identification, assay limits, and impurity thresholds. Manufacturers often follow these monographs or internal specifications to ensure batch-to-batch consistency. Analytical method validation is important because different methods can yield different apparent purity values if sample preparation or detection conditions are not controlled.
Quality control for creatine monohydrate begins with identity confirmation and assay determination. Laboratories commonly use high-performance liquid chromatography with ultraviolet detection, often after derivatization or using a suitable column, to quantify creatine. Karl Fischer titration measures water content, which helps verify the monohydrate stoichiometry. Additional tests screen for heavy metals, residual solvents, and microbial contamination depending on the intended use. These tests establish composition and purity rather than biological effect.
For adult men, as oral doses were increased from 0.5 mg to 1.1 mg, there was a modest linear increase in urinary riboflavin, reaching 100 micrograms for a subsequent 24-hour urine collection. Beyond a load dose of 1.1 mg, urinary excretion increased rapidly, so that with a dose of 2.5 mg, urinary output was 800 micrograms for a 24-hour urine collection.
Aggregated proteins are associated with prion-related illnesses such as Creutzfeldt–Jakob disease, bovine spongiform encephalopathy (mad cow disease), amyloid-related illnesses such as Alzheimer's disease and familial amyloid cardiomyopathy or polyneuropathy, as well as intracellular aggregation diseases such as Huntington's and Parkinson's disease. These age onset degenerative diseases are associated with the aggregation of misfolded proteins into insoluble, extracellular aggregates and/or intracellular inclusions including cross-β amyloid fibrils. It is not completely clear whether the aggregates are the cause or merely a reflection of the loss of protein homeostasis, the balance between synthesis, folding, aggregation and protein turnover. Recently the European Medicines Agency approved the use of Tafamidis or Vyndaqel (a kinetic stabilizer of tetrameric transthyretin) for the treatment of transthyretin amyloid diseases. This suggests that the process of amyloid fibril formation (and not the fibrils themselves) causes the degeneration of post-mitotic tissue in human amyloid diseases. Misfolding and excessive degradation instead of folding and function leads to a number of proteinopathies, diseases such as antitrypsin-associated emphysema, cystic fibrosis and the lysosomal storage diseases, where loss of function is the origin of the disorder. While protein replacement therapy has historically been used to correct the latter disorders, an emerging approach is to use pharmaceutical chaperones to fold mutated proteins to render them functional.
==== Indonesia ==== In 2008, 7-Eleven announced plans to expand its business in Indonesia through a master franchise agreement with Modern Sevel Indonesia. Modern Sevel Indonesia's initial plans were to focus on opening stores in Jakarta, targeting densely populated commercial and business areas. There were 190 7-Eleven stores in Indonesia as of 2014 which then reduced to only 166 stores in September 2016. 7-Eleven then closed its doors in Indonesia in 2017, citing low sales.
== Storage and preservation == Storehouses, which were used primarily for military purposes, were used by the Inca to facilitate traveling over long distances. Being placed conveniently along major travel routes, the storehouses acted as a place of refuge when it came to the restocking of resources. Location was chosen strategically for the purpose of securing a cooler area characterized by higher ventilation to prevent rotting of perishable items. Perishable foods ranged, while some were prepared to a certain extent, some were completely untreated. Freeze-dried foods were common in the storehouses, such as ch'arki, which is a form of dried meat. Additionally, potato tubers were freeze-dried and stored as chuño. Storehouses quickly became a valued practice for the Inca, but were limited at times when communities prioritized local growth of foods, instead. Archaeologists have excavated ceramic vessels that provide evidence for different types of storage and preservation methods. Aríbalos, vessels with high flaring necks and cone-shaped bases, are interpreted to have been used as a way of storing chicha. Additionally, ceramic vessels could have been used for storage of foods in water or for long-term preparation methods.
==== Particle transport ==== The ocean is an extensive network of particle transport. Thorium isotopes can help researchers decipher the vertical and horizontal movement of matter. 234Th has a constant, well-defined production rate in the ocean and a half-life of 24 days. This naturally occurring isotope has been shown to vary linearly with depth. Therefore, any changes in this linear pattern can be attributed to the transport of 234Th on particles. For example, low isotopic ratios in surface water with very high values a few meters down would indicate a vertical flux in the downward direction. Furthermore, the thorium isotope may be traced within a specific depth to decipher the lateral transport of particles.
Sources: en.wikipedia.org
Hong Kong is governed by a hybrid regime that is not fully representative of the population. Legislative Council members elected by functional constituencies composed of professional and special-interest groups are accountable to narrow corporate electorates rather than the general public. This electoral arrangement has ensured a pro-Beijing majority in the legislature since the handover. Similarly, the chief executive is selected by establishment politicians and corporate members of the Election Committee rather than directly elected. Despite universal suffrage being established as ultimate goals for the election of the chief executive and all members of the Legislative Council in Articles 45 and 68 of the basic law, the legislature is only partially directly elected, and the executive continues to be nominated by an unrepresentative body. The government has been repeatedly petitioned to introduce direct elections for these positions, but has not introduced these direct elections as of 2026. Ethnic minorities (except those of European ancestry) have marginal representation in government and often experience discrimination in housing, education, and employment. Employment vacancies and public service appointments frequently have language requirements that minority job seekers do not meet, and language education resources remain inadequate for Chinese learners. Foreign domestic helpers, mostly women from the Philippines and Indonesia, have little protection under regional law.
In spectroscopy, absorbance (abbreviated as A) is a logarithmic value which describes the portion of a beam of light which does not pass through a sample. Whilst the name refers to the absorption of light, other interactions of light with a sample (reflection, scattering) may also contribute to attenuation of the beam passing through the sample. The term "internal absorbance" is sometimes used to describe beam attenuation caused by absorption, while "attenuance" or "experimental absorbance" can be used to emphasize that beam attenuation can be caused by other phenomena.
In the late 1990s, Smith's group was also extensively involved in the development and application of Fourier transform ion cyclotron resonance (FTICR) mass spectrometry, which provided the basis for much greater MS resolution and mass measurement accuracy, and particularly in the development of these technologies for applications in proteomics. More recent work has centered on extending application of these proteomics technologies to mammalian systems, which pose additional challenges due to their much greater complexity. One early focus has been the human blood plasma proteome due to its broad biomedical applications. Plasma proteome measurements potentially can provide the basis for discovery of protein biomarkers or signatures for virtually every disease state. In September 1999, R&D Magazine picked the top 40 technologies of all time based on their impact on society, industry and commercial applications. The Top 40 were selected from a list of 3,600 past R&D 100 Awards. Smith was the recipient of one of these awards, for the development of capillary electrophoresis-mass spectrometry.
In the 2000s, Knoxville's planners turned their focus to the development of mixed residential and commercial neighborhoods (such as the Old City), cohesive, multipurpose shopping centers (such as Turkey Creek in West Knoxville), and a Downtown area with a mixture of unique retailers, restaurants, and cultural and entertainment venues, all with considerable success. In 2020, March 23, Knoxville businesses were shut down due to the COVID-19 pandemic.
Sources: en.wikipedia.org
== Introduction == The two primary classes of therapeutics are small molecules and protein therapeutics. The design of small molecule inhibitors of protein-protein interactions (PPIs) has been impeded by issues such as the general lack of small-molecule starting points for drug design, the typical flatness of the interface, the difficulty of distinguishing real from artifactual binding, and the size and character of typical small-molecule libraries. Meanwhile, the protein therapeutics that lack these issues are bedeviled by another problem, poor cell penetration due to an insufficient ability to diffuse across the cell membrane. Additionally, proteins and peptides are often subject to proteolytic degradation in vivo or if they do enter the cell. Furthermore, small peptides (such as single alpha-helices or α-helices) can lose helicity in solution due to entropic factors, which diminishes binding affinity. α-Helices are the most common protein secondary structure and play a key role in mediating many PPIs by serving as recognition motifs. PPIs are frequently misregulated in disease, providing the long-running impetus to create alpha-helical peptides to inhibit disease-state PPIs for clinical applications, as well as for basic science applications. Introducing a synthetic brace (staple) helps to lock a peptide in a specific conformation, reducing conformational entropy. This approach can increase target affinity, increase cell penetration, and protect against proteolytic degradation.
A woman's breasts change in size, volume, and position on her chest throughout her life. In young women with large breasts, sagging may occur early in life due to the effect of gravity. It may be primarily caused by the volume and weight of the breasts which are disproportionate to her body size.
== History == The lines were first discovered in 1861 by Austrian anatomist Karl Langer (1819–1887), though he cited the surgeon Baron Dupuytren as being the first to recognise the phenomenon. Langer punctured numerous holes at short distances from each other into the skin of a cadaver with a tool that had a circular-shaped tip, similar to an ice pick. He noticed that the resultant punctures in the skin had ellipsoidal shapes. From this testing he observed patterns and was able to determine "line directions" by the longer axes of the ellipsoidal holes and lines.
Sources: en.wikipedia.org
Creatine is the base compound, while creatine monohydrate includes one water molecule per creatine molecule in its crystal structure. The monohydrate form is common in supplements and analytical standards. The body uses creatine itself after the water is removed or dissociated.
Yes. Meat, fish, and other animal tissues contain creatine. Cooking can convert some creatine to creatinine, which has no role in phosphocreatine energy buffering. Plant foods contain little or no creatine.
Creatinine is a cyclic breakdown product formed from creatine and phosphocreatine. It is filtered by the kidneys and commonly measured in blood and urine as a marker of renal function. Creatine monohydrate is a supplement ingredient and research chemical, not the same molecule.
Purity testing often uses high-performance liquid chromatography to measure creatine and creatinine. Water content can be checked by Karl Fischer titration. Additional tests may cover heavy metals, residual solvents, and microbial contamination.