Guanidinium group raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
Commercial creatine monohydrate is typically manufactured through chemical synthesis, often starting from sarcosine and cyanamide. The resulting material is crystallized, washed, and dried to a specified hydrate content. Finished lots are tested for identity, purity, moisture, and heavy metals before release. Because the compound can cyclize to creatinine under heat or prolonged storage in solution, manufacturers control temperature and humidity during processing. The solid itself is relatively stable when kept dry and sealed, but moisture uptake can cause caking and complicate accurate assay.
Analytical laboratories commonly identify creatine monohydrate by high-performance liquid chromatography with ultraviolet detection, often after dissolving the sample in water or dilute acid. Ion-exchange or reversed-phase columns separate creatine from creatinine and related guanidino compounds. Nitrogen content can be checked by Kjeldahl or combustion methods, while moisture is measured by Karl Fischer titration or loss on drying. These techniques give complementary views: chromatographic purity addresses related substances, whereas moisture and elemental data confirm hydrate stoichiometry. No single test defines quality by itself; a combination is used in specifications.
Storage recommendations generally emphasize a cool, dry place away from direct sunlight and strong oxidizers. Sealed containers limit humidity exchange, which helps prevent clumping and gradual conversion to creatinine. Long-term stability studies usually monitor appearance, moisture, and purity at intervals under defined temperature and humidity conditions. Accelerated tests at elevated temperature can reveal degradation pathways, but they do not perfectly predict room-temperature shelf life. Questions remain about how much creatinine formation is acceptable in different product categories and how packaging choices affect that rate over time.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C4H11N3O3·H2O | Hydrated form includes one water molecule per creatine unit. |
| Molar mass | 149.15 g/mol | Calculated for the monohydrate form. |
| Appearance | White crystalline powder | Common commercial grade is odorless or nearly odorless. |
| Solubility in water | Moderately soluble | Solubility increases with temperature and depends on pH. |
| Common synonyms | Creatine hydrate; N-methylguanidinoacetic acid | Monohydrate distinguishes it from anhydrous creatine. |
Creatine monohydrate is stable under dry, cool conditions but can degrade when exposed to moisture and heat. In solution, it undergoes hydrolysis to creatinine, a cyclic derivative with little role in phosphagen energy transfer. The rate of conversion increases with temperature, storage time, and acidic or alkaline pH. Solid material kept in a sealed container at room temperature generally retains its composition for extended periods. Moisture uptake is a primary concern because it can accelerate breakdown and caking.
Analytical laboratories commonly use high-performance liquid chromatography to separate creatine from creatinine and related impurities. Ion chromatography, nuclear magnetic resonance, and titration assays can also quantify the compound. Water content is measured by Karl Fischer titration or loss on drying, because the monohydrate has a defined theoretical water fraction. Particle size, bulk density, and flowability are physical properties that affect blending and capsule filling. These measurements support quality control and help verify that a lot matches its specification.
Regulatory status varies by country. In the United States, creatine monohydrate is sold as a dietary supplement ingredient, while in the European Union it is placed on the market as a food supplement component. Some jurisdictions have established purity monographs or permitted health claims, while others treat it as a novel food or require notification. Product labels may state the amount of creatine monohydrate or the equivalent creatine content, and the two figures can differ. Independent testing programs sometimes check identity, potency, and contaminant limits.
The compound was identified in the nineteenth century after chemists isolated a nitrogenous substance from meat extracts. Later work established its role in muscle energy metabolism and its conversion to phosphocreatine. Chemical synthesis of creatine followed, and industrial production made the monohydrate widely available as a purified powder. Interest expanded in the late twentieth century when researchers began studying creatine supplementation and muscle physiology. Historical accounts sometimes differ on exact dates and attributions, but the broad sequence from tissue extracts to synthetic production is well documented.
In the body, creatine is obtained from dietary meat and fish and is also synthesized from arginine, glycine, and methionine. Muscle stores creatine and phosphocreatine, which participate in the rapid regeneration of adenosine triphosphate during short, intense activity. The monohydrate form is used in research because it is chemically defined, stable as a dry solid, and relatively inexpensive to produce. Questions remain about whether other creatine forms offer meaningful advantages in absorption or tissue retention, and findings vary across studies and populations.
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.
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.
Arthur Guinness started brewing ales in 1759 at the St. James's Gate Brewery, Dublin. On 31 December 1759, he signed a 9,000 year lease at £45 per annum for the unused brewery, and it would become one of the largest in the British Empire. Arthur Guinness started selling porter in 1778. The first Guinness beers to use the term "stout" were Single Stout and Double Stout in the 1840s. Throughout the bulk of its history, Guinness produced only three variations of a single beer type: porter or stout (single, double or extra) and foreign stout for export. "Stout" originally referred to a beer's strength, but eventually shifted meaning toward body and colour. Porter was also referred to as "plain", as mentioned in the famous refrain of Flann O'Brien's poem "The Workman's Friend": "A pint of plain is your only man." Already one of the top-three British and Irish brewers, Guinness's sales soared from 350,000 barrels in 1868 to 779,000 barrels in 1876. In October 1886, Guinness became a public company and was averaging sales of 1.138 million barrels a year. This was despite the brewery's refusal to either advertise or offer its beer at a discount. Even though Guinness owned no public houses, the company was valued at £6 million and shares were 20 times oversubscribed, with share prices rising to a 60 per cent premium on the first day of trading. The breweries pioneered several quality control efforts.
Modern practice therefore often involves an iterative process: field lichenologists may initially distinguish entities by appearance ("morphospecies"), then genetic analysis (often multilocus) is used to test those hypotheses, merging or splitting as needed. Others invert the sequence: barcode data first reveal genetic clusters, which are then searched for overlooked diagnostic traits ("L then P"). Either way, multiple evidence lines—rather than their order—are the requirement. Coalescent-based models now estimate how many genetic lineages in a lichen group merit species rank. The models incorporate incomplete lineage sorting and ongoing gene flow. Results usually recognize more species than morphology alone, suggesting widespread cryptic speciation. A purely genetic approach can oversplit when it treats every population divergence as a new species. Lücking and colleagues (2021) warn that genome-scale data make every population diagnosable; genetic structure must therefore be interpreted biologically to avoid a proliferation of trivial taxa. They advocate pairing genetics with quantitative phenotype data (morphometrics, metabolite profiles) to test discontinuities and confirm genuine species boundaries.
List of nuclides shows all radionuclides with half-life > 1 hour Hyperaccumulators table – 3 (includes organisms noted for accumulating radionuclides) Radioactivity in biology Radiometric dating Radionuclide cisternogram Uses of radioactivity in oil and gas wells
Sources: en.wikipedia.org
== Causes == Adverse drug reactions are classified as type A (intrinsic or pharmacological) or type B (idiosyncratic). Type A drug reaction accounts for 80% of all toxicities. Drugs or toxins that have a pharmacological (type A) hepatotoxicity are those that have predictable dose-response curves (higher concentrations cause more liver damage) and well characterized mechanisms of toxicity, such as directly damaging liver tissue or blocking a metabolic process. As in the case of paracetamol overdose, this type of injury occurs shortly after some threshold for toxicity is reached. Carbon tetrachloride is commonly used to induce acute type A liver injury in animal models. Idiosyncratic (type B) injury occurs without warning, when agents cause non-predictable hepatotoxicity in susceptible individuals, which is not related to dose and has a variable latency period. This type of injury does not have a clear dose-response nor temporal relationship, and most often does not have predictive models. Idiosyncratic hepatotoxicity has led to the withdrawal of several drugs from market even after rigorous clinical testing as part of the FDA approval process; Troglitazone (Rezulin) and trovafloxacin (Trovan) are two prime examples of idiosyncratic hepatotoxins pulled from market. The herb kava has caused a number of cases of idiosyncratic liver injury, ranging everywhere from asymptomatic to fatal.
tRFs are not restricted to humans and have been shown to exist in multiple organisms. Two online tools are available for those wishing to learn more about tRFs: the framework for the interactive exploration of mitochondrial and nuclear tRNA fragments (MINTbase) and the relational database of Transfer RNA related Fragments (tRFdb Archived 2024-03-15 at the Wayback Machine). MINTbase also provides a naming scheme for the naming of tRFs called tRF-license plates (or MINTcodes) that is genome independent; the scheme compresses an RNA sequence into a shorter string.
=== Layne Staley Day in Seattle === On August 22, 2019, which would have been Staley's 52nd birthday, Seattle mayor Jenny Durkan officially proclaimed that day as "Layne Staley Day" in the city in honor of Staley's contributions to the world of music. The day was also a call to attention to the Layne Staley Memorial Fund, established by his parents in 2002.
Sources: en.wikipedia.org
=== Semiconductor industry support === DASH7 developers receive support from the semiconductor industry including multiple options, with Texas Instruments, ST Microelectronics, Silicon Labs, Semtech and Analog Devices all offering DASH7-enabled hardware development kits or system-on-a-chip products.
After optimizing the concentration of graphene oxide concentration and anisotropic porous structure, tensile tests were performed. It was found that MGCA could recover 99.8% and 96.3% when compressed to 60% and 90% strain, respectively. SEM images showed that due to its unique structure, MCGA pore walls were able to wrinkle and fold during compression. Another unique characteristic of this material is its absorption capacity of 80-197 times its weight towards hydrophobic compounds, such as oils and chemical solvents. On the contrary, less effort has been made to study the stretchability of porous carbons. Gao, et al. synthesized a long-range lamellar scaffold composed of chitosan and graphene oxide via bidirectional freezing, freeze drying, and annealing. The result is a material with density of 11 mg cm−3 and porosity of about 99.4%. Various tensile tests were conducted, and it was found that carbon spring could revert to its original shape upon 80% compression strain and -60% stretching strain with a Poisson's ratio between 0.05 and 0.1. The narrow hysteresis loop of the stress-strain curve indicates a low energy dissipation (energy loss coefficient of about 0.2) because of its negligible interior friction, localized buckling, or cracks during deformation processes. The stretchable mechanical properties of this material allow for great candidates for vibrational and magnetism sensors.
Insulin shock therapy or insulin coma therapy was a form of psychiatric treatment in which patients were repeatedly injected with large doses of insulin in order to produce daily comas over several weeks. It was introduced in 1927 by Austrian-American psychiatrist Manfred Sakel and used extensively in the 1940s and 1950s, mainly for schizophrenia, before falling out of favour and being replaced by neuroleptic drugs in the 1960s. It was one of a number of physical treatments introduced into psychiatry in the first four decades of the 20th century. These included the convulsive therapies (cardiazol/metrazol therapy and electroconvulsive therapy), deep sleep therapy, and psychosurgery. Insulin coma therapy and the convulsive therapies are collectively known as the shock therapies.
The relationship between sex steroids and SHBG in physiological and pathological conditions is complex, as various factors may influence the levels of plasma SHBG, affecting bioavailability of testosterone.
Sources: en.wikipedia.org
In common usage, yes, but technically creatine monohydrate is one specific hydrated salt form. Other creatine forms exist and differ in composition and properties. The monohydrate is the most studied and most widely available grade.
Yes. Each creatine molecule in the crystal is associated with one water molecule. That water contributes to the total mass but is not part of the creatine molecule itself. Heating or drying can remove some or all of this water.
It occurs naturally in meat and fish, and the human body also makes and stores creatine. Food sources provide varying amounts depending on the type and preparation. The compound is not considered an essential dietary nutrient for adults because the body can synthesize it.
Laboratories typically combine chromatographic separation with moisture and elemental analysis. High-performance liquid chromatography can quantify creatine and related substances such as creatinine. Moisture methods confirm the hydrate form and help detect excess water.