This is a working overview of Guanidino group, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-09-04. Anything still debated is marked as such rather than presented as settled.
Several creatine forms are sold, including monohydrate, anhydrous, hydrochloride, nitrate, citrate, and blends. Once dissolved, these forms deliver creatine, but they differ in molar mass, solubility, counterions, and water content. Creatine monohydrate has the largest body of published human data among these forms. Questions remain about whether any alternative form offers meaningful advantages in absorption, tolerability, or tissue uptake under practical conditions. The hydrate form's lower creatine content by mass is a compositional fact, not a statement about effectiveness.
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 was first identified in skeletal muscle extracts in the nineteenth century, and its role in phosphagen energy buffering was clarified in the twentieth century. The monohydrate salt became widely studied after methods for inexpensive synthesis and crystallization were developed. Modern research examines its effects on muscle energetics, recovery, and cognitive performance under specific conditions. Findings vary with population, exercise protocol, baseline creatine status, and measurement method. Studies often compare supplementation with placebo during controlled training or testing schedules.
Creatine monohydrate is a hydrated form of creatine, a nitrogen-containing compound involved in cellular energy metabolism. Its molecular formula is C4H9N3O2·H2O, with a molar mass around 149.15 g/mol. The monohydrate is the most common solid form used in research and commercial settings because it crystallizes readily and remains stable under ordinary conditions. The term monohydrate indicates one water molecule per creatine molecule in the crystal lattice. It appears as a white crystalline powder with low odor.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C4H11N3O3 | Often written C4H9N3O2·H2O |
| Molar mass | 149.15 g/mol | Anhydrous creatine is 131.13 g/mol |
| Appearance | White crystalline powder | Odorless, fine or granular |
| Water solubility | About 13 g/L at 25 °C | Low; increases with temperature |
| Common synonyms | Creatine hydrate; N-carbamimidoylsarcosine monohydrate | CAS 6020-87-7 |
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 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.
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.
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.
Creatine monohydrate is one of several solid forms of creatine described in the literature. Other forms include anhydrous creatine, creatine hydrochloride, and creatine ethyl ester, each with different solubility and stability characteristics. The monohydrate is distinct from creatinine, a spontaneous breakdown compound that forms when creatine loses water and cyclizes. Commercial descriptions sometimes use synonyms such as methylguanidoacetic acid or N-(aminoiminomethyl)-N-methylglycine, which refer to the same base molecule. These names appear in chemical databases and product labels.
Creatine monohydrate is a crystalline compound formed when one molecule of creatine binds with one molecule of water. Creatine itself is a nitrogen-containing organic acid involved in cellular energy transfer, particularly in muscle and nerve tissue. The monohydrate form is the most common solid form used in research and commercial products because it is relatively stable and easy to handle. Its molecular formula is C4H9N3O2·H2O, and its molar mass is about 149.15 grams per mole.
In the human body, creatine is synthesized mainly in the liver and kidneys from the amino acids glycine, arginine, and methionine. Dietary sources include meat, fish, and other animal tissues, which supply preformed creatine. Because plant foods contain little or no creatine, dietary intake varies widely among populations. The compound is stored largely in skeletal muscle, where it is converted to phosphocreatine and used to regenerate adenosine triphosphate during short bursts of activity.
It contained an immense rectangular hall, 55 metres long, 25 wide, and 15 metres high, supported by forty slender cast-iron columns, and was originally covered with a glass roof one thousand square metres in size. The building suffered from technical problems, and was closed entirely in 1965. It was extensively remodelled between 1991 and 1994 and reopened in its present form. The great central hall, kept in its same form but enlarged during the modernisation, is devoted to the presentation of marine animals on the lower sides, and, on a platform in the centre, a parade of full-size African mammals, including a rhinoceros originally presented to King Louis XV in the 18th century. On the garden side is another hall, in its original size, devoted to animals which have disappeared or are in danger of extinction.
== Awards and honors == 1983 - HVA Briscoe Prize 1987 - Du Pont Young Faculty Fellow 1991 - Meldola Medal and Prize by Royal Society of Chemistry 1992 to 1994 - Alcoa Directors Fellowship 1995 - Corday Morgan Medal and Prize 1995 - Fellow, Royal Society of Chemistry 1997 - Hümboldt Senior Scientist Research Award 2002 - Welch Foundation Norman Hackerman Award in Chemical Research 2009 - Prince of Wales Visiting Innovator 2011 - Lifetime Achievement Award in Nanotechnology 2011 - World Technology Award (Materials) 2013 - Applied Inorganic Chemistry Award (Royal Society of Chemistry) 2016 - Erasmus+ Vilnius University 2019 - Star of Asia Award 2020 - Adjunct Professor University of Technology Brunei
Healing her requires Gordon to make a dangerous trek through an Antlion colony to retrieve their "larval extract," an essential ingredient in the Vortigaunt healing process. As part of the healing process, her life is entwined with Gordon's. During this time, the G-Man appears to Gordon in a surreal "heart-to-heart" sequence and programs Alyx to tell her father to "prepare for unforeseen consequences." Once Alyx awakens, she and Gordon resume their quest toward White Forest. She delivers the Combine data to Dr. Kleiner, who manages to decrypt it and discover that Judith Mossman has found the legendary Borealis, an icebreaker ship which has disappeared during teleportation experiments. She delivers the message to her father after the G-Man triggers her programming, and later, two creatures called Advisors break in and kill Eli before Dog saves Gordon and Alyx. Alyx is the titular playable protagonist of the 2020 virtual reality game Half-Life: Alyx developed by Valve. The game follows a 19-year-old Alyx's story in City 17 five years before the events of Half-Life 2. Initially performing routine reconnaissance for the Resistance, Alyx is captured along with her father by the Combine after he discovers images relating to an apparent Combine superweapon called "the Vault." Russell, a Resistance mechanic, frees Alyx and sends her through the zombie-infested Quarantine Zone outside City 17 to rescue Eli. Along the way, Alyx meets an eccentric Vortigaunt who warns her of Eli's death in the future.
Empagliflozin/linagliptin, sold under the brand name Glyxambi, is a fixed-dose combination anti-diabetic medication used to treat type 2 diabetes. It is a combination of empagliflozin and linagliptin. It is taken by mouth. The most common side effects include urinary infections, nasopharyngitis, and upper respiratory tract infections . It was approved for use in the United States in January 2015, for use in the European Union in November 2016, and for use in Australia in December 2016.
Meyerowitz expanded this rhetoric through a series of publications that sought to reconstruct early history. She claimed that Akan origins and culture came from areas in the Sahara and the Near East, and argued that Akan culture was not mainly black African, but could instead be considered Libya-Berber or connected to Mediterranean or Near Eastern cultures.
Sources: en.wikipedia.org
==== D. Lymphatic system of the nose ==== The pertinent nasal lymphatic system arises from the superficial mucosa, and drains posteriorly to the retropharyngeal nodes (in back), and anteriorly (in front), either to the upper deep cervical nodes (in the neck), or to the submandibular glands (in the lower jaw), or into both the nodes and the glands of the neck and the jaw.
The Br–Br distance is 227 pm (close to the gaseous Br–Br distance of 228 pm) and the Br···Br distance between molecules is 331 pm within a layer and 399 pm between layers (compare the van der Waals radius of bromine, 195 pm). This structure means that bromine is a very poor conductor of electricity, with a conductivity of around 5 × 10−13 Ω−1 cm−1 just below the melting point, although this is higher than the essentially undetectable conductivity of chlorine. At a pressure of 55 GPa (roughly 540,000 times atmospheric pressure) bromine undergoes an insulator-to-metal transition. At 75 GPa it changes to a face-centered orthorhombic structure. At 100 GPa it changes to a body centered orthorhombic monatomic form.
=== Educational goals === John White (2013) investigated the educational goals at public schools in Britain. School-education involves both cognitive and conceptual learning, but also the development social skills and personal development. Ideally, children develop self-confidence, and create purpose for themselves. According to White, in the past schools only focused on knowledge and education but now Britain has moved to a broader direction. White's Every Child Matters initiative seeks to enhance children's well-being across the range of children's services.
Acetoxolutamide is a nonsteroidal androgen and selective androgen receptor modulator (SARM) which was described in 2000 and was never developed or marketed for medical use. It was derived from structural modification of the nonsteroidal antiandrogen bicalutamide and the nonsteroidal SARM acetothiolutamide. Acetoxolutamide shows greatly improved pharmacokinetic properties and anabolic and androgenic potency relative to acetothiolutamide in animals. It is the (2R) enantiomer of andarine (also known as acetamidoxolutamide or androxolutamide).
Sources: en.wikipedia.org
PABA and its salts are used in nutritional epidemiological studies to assess the completeness of 24-hour urine collection for the determination of urinary sodium, potassium, or nitrogen levels. The potassium salt (potassium paraaminobenzoate, "aminobenzoate potassium") is used as a drug against fibrotic skin disorders, such as Peyronie's disease, under the brand name Potaba. There is a lack of strong evidence. It is believed to work by inhibiting fibroblast glycosaminoglycan secretion and stabilizing monoamine oxidase A activity. PABA is also occasionally used in pill form by sufferers of irritable bowel syndrome to treat its associated gastrointestinal symptoms. PABA derivatives have also been proposed to function as acetylcholinesterase inhibitors in diseases that cause deficient cholinergic systems, such as Alzheimer's disease.
For the Kharaa (alien) side, winning requires destroying all marine "Infantry Portals", ensuring that they do not respawn, and then eliminating the rest of the marines. Other possibilities exist such as destroying the command chair, or destroying all finished hives, and killing the whole alien team before the remaining hive is fully grown. Game duration and game balance has been continually addressed by Unknown Worlds Entertainment throughout each of their releases with extensive changelogs describing these issues. In v1, games were slower and often measured in hours. One of the stated aims of v2 was to address this, by introducing a broad range of changes to abilities, structures, etc. In current releases (v3), a typical game lasts 5–15 minutes, but can run over an hour, with both sides vying for control over strategically important Hive Rooms and Resource Nodes. Combat is the team deathmatch, or beginner mode of NS. It was introduced in NS 3.0 to help new players learn how to play alien lifeforms in an easier environment. Neither team can build structures, the marines do not have a commander, and aliens have only one hive. Each player has an individual experience meter, increased by killing enemies; dealing damage to the enemy hive/command chair or healing/repairing their own hive/command chair. When the experience meter reaches maximum, the player gains a level and it resets.
Gas phase regioselectivity is calculated to favor 1,5 addition over 1,4 addition by up to 2.9 kcal/mol in activation energy in the gas phase; solvation corrections give the same energy barriers for both regioisomers, explaining the regioisomeric mix that results from DIFO cycloadditions. While the 1,4 isomer is disfavored by its larger dipole moment (all electron-rich substituents on one side), solvation stabilizes it more strongly than the 1,5 isomer, eroding regioselectivity. Experimental studies by Carolyn R. Bertozzi report a nearly 1:1 ratio of regioisomers, confirming the predicted lack of regioselectivity in the addition. Furthermore, nearly all of the distortion energy (92%) arises from the distortion of the 1,3 dipole rather than the cyclooctyne, which has a pre-distorted ground state geometry that increases its reactivity. Fluorination decreases the distortion energy by allowing the transition state to be achieved with a lesser distortion of the 1,3-dipole during a reaction, resulting in a larger dipole angle.
Sources: en.wikipedia.org
It is the hydrated crystalline form of creatine, containing one bound water molecule per creatine unit. The compound is commonly used as a nutritional ingredient and as a research material.
Yes, endogenous synthesis occurs mainly in the liver, kidney, and pancreas. Meat and fish also contribute creatine to the diet.
Other forms contain creatine paired with different counterions or lacking water, so their mass and solubility differ. After dissolution, creatine itself is the shared active molecule.
Creatine is the base compound, while creatine monohydrate is a solid crystalline form that contains one water molecule per creatine molecule. Once dissolved, the monohydrate dissociates and releases creatine, which can participate in cellular energy metabolism. The monohydrate is the form most commonly used in research and commercial products.