A practical reference on creatine: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-02-16 and is reviewed periodically as new material appears.
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.
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.
In the body, creatine is synthesized from arginine, glycine, and methionine, mainly in the liver and kidneys, and is also obtained from foods such as meat and fish. About 95% of body creatine is stored in skeletal muscle, where a fraction is phosphorylated to phosphocreatine. Phosphocreatine serves as a rapid reserve of high-energy phosphate for short bursts of ATP regeneration. The monohydrate form supplies creatine after dissolution and absorption, but it is not itself the active phosphorylated species.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C4H9N3O2·H2O | Monohydrate includes one water molecule per creatine molecule |
| Molar mass | 149.15 g/mol | Value for the monohydrate; anhydrous creatine is about 131.13 g/mol |
| Appearance | White crystalline powder | Odorless or nearly odorless in purified form |
| Solubility in water | About 13 g/L at 25 °C | Solubility increases with temperature and varies with pH |
| Common synonyms | Creatine hydrate; N-(aminoiminomethyl)-N-methylglycine | Monohydrate distinguishes it from anhydrous creatine |
Identity and purity are assessed with several complementary methods. High-performance liquid chromatography can separate creatine from creatinine and related impurities, often with ultraviolet detection. Nuclear magnetic resonance and infrared spectroscopy provide structural confirmation, while Karl Fischer titration measures water content. Elemental analysis and mass spectrometry may be used for additional confirmation, especially in research or forensic settings. No single method captures every quality attribute, so laboratories typically combine results and compare them against a specification.
Creatine monohydrate is sold as a dietary ingredient in some countries and as a food supplement in others. Regulatory frameworks vary, so purity limits, labeling rules, and permitted claims are not globally uniform. In the United States, it falls under dietary supplement rules, whereas the European Union treats it as a food supplement ingredient. Pharmacopeial monographs, where they exist, can provide public quality standards, but not every product is required to meet them. Questions about long-term effects and patterns of use remain areas of active study rather than settled regulatory findings.
Solid creatine monohydrate is generally stable when kept cool and dry, but it can hydrolyze to creatinine over time. Moisture, heat, and acidic conditions accelerate this conversion, which reduces assay values and changes the material's properties. Creatinine is a cyclic dehydration product that is also a normal human metabolite, so its presence in a sample is not necessarily a health concern by itself. In quality testing, creatinine is monitored as a marker of degradation and purity.
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.
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.
== History == About 1939 or 1940 Antonio Rodilla opened a confectionery shop in Callao Square in downtown Madrid. After some years he decided to sell a new line of products, cold meat (fiambre) sandwiches. Since it was difficult at the time to find a good bread supplier he decided to make his own sliced bread as well, called "English bread", or pan de molde (as opposed to the more traditional baguette-like bread). In the early 1970s Rodilla opened two new establishments in Princesa and Orense streets, and in 1992 the new firm Artesanía de la Alimentación was created to centralize the production of their own raw materials.
In 1989, most Warsaw Pact countries overthrew their Soviet-backed regimes, effectively ending the Eastern Bloc. Nationalist movements across the Soviet republics declared sovereignty, and in 1991, a successful referendum to establish a renewed federation was followed by a failed coup by hardliners. This prompted Russia, Ukraine, and Belarus to secede. On 26 December, Gorbachev officially recognized the dissolution of the Soviet Union. Boris Yeltsin, president of the Russian SFSR, oversaw its reconstitution into the Russian Federation, the Soviet Union's successor state. All fifteen republics became independent states; all except the Baltic states joined the Commonwealth of Independent States. The post-Soviet states experienced a humanitarian disaster and continuing wars and insurgencies. The Soviet Union was one of the world's two superpowers, with hegemony in Eastern Europe, global diplomacy, ideological influence (particularly in the Global South), military might, economic strength, and scientific and technological accomplishments. Its space program made significant achievements in the Space Race. It had the world's second-largest economy and the largest standing military. As a nuclear state, it wielded the largest arsenal of nuclear weapons in the world. As an Allied nation, it was a founding member of the United Nations and one of five permanent members of its Security Council.
The researchers suggested that in order to achieve equivalent exposure, based on an average dose of 100%, the dosage of doxepin might be adjusted to 250% in ultra-rapid metabolizers, 150% in extensive metabolizers, 50% in intermediate metabolizers, and 30% in poor metabolizers.
Sources: en.wikipedia.org
Carbonylation of alcohols as illustrated by the Cativa process for the production of acetic acid. Formic acid is prepared by a different carbonylation pathway, also starting from methanol. Oxidation of aldehydes with air using cobalt and manganese catalysts. The required aldehydes can be obtained from alkenes by hydroformylation. Oxidation of hydrocarbons using air. For simple alkanes, this method is inexpensive but not selective enough to be useful. Allylic and benzylic compounds undergo more selective oxidations. Alkyl groups on a benzene ring are oxidized to the carboxylic acid, regardless of its chain length. Benzoic acid from toluene, terephthalic acid from para-xylene, and phthalic acid from ortho-xylene are illustrative large-scale conversions. Acrylic acid is generated from propene. Hydrocarboxylation of alkenes. This method is effective for alkenes that generate secondary and tertiary carbocations, e.g. isobutylene to pivalic acid. In the Koch reaction, the addition of water and carbon monoxide to alkenes or alkynes is catalyzed by strong acids. Hydrocarboxylations involve the simultaneous addition of water and CO. Such reactions are sometimes called "Reppe chemistry." HC≡CH + CO + H2O → CH2=CH−CO2H Hydrolysis of esters. Triglycerides, obtained from plant or animal oils, are precursors to long-chain carboxylic acids are related to soap making. Fermentation of ethanol. This method is used in the production of vinegar. Carbonation, such as the Kolbe–Schmitt reaction as a route to salicylic acid, precursor to aspirin.
== Further reading == Batchelor, G.K (2012), An Introduction to Fluid Dynamics, Cambridge University Press, doi:10.1017/CBO9780511800955, ISBN 9780511800955 Falkovich, Gregory (2011), Fluid Mechanics (A short course for physicists), Cambridge University Press, doi:10.1017/CBO9780511794353, ISBN 978-1-107-00575-4 Kundu, Pijush K.; Cohen, Ira M.; Dowling, David R.; Capecelatro, Jesse (2025), Fluid Mechanics (7th ed.), Academic Press, ISBN 978-0-12-819807-0 Currie, I. G. (1974), Fundamental Mechanics of Fluids, McGraw-Hill, Inc., ISBN 0-07-015000-1 Massey, B.; Ward-Smith, J. (2005), Mechanics of Fluids (8th ed.), Taylor & Francis, ISBN 978-0-415-36206-1 Nazarenko, Sergey (2014), Fluid Dynamics via Examples and Solutions, CRC Press (Taylor & Francis group), ISBN 978-1-43-988882-7
During the early phase of the investigation, much attention and media speculation fell on the anti-obesity supplement AOD-9604, which had appeared on consent forms and was acknowledged to have been administered in the program, including by Essendon captain Jobe Watson during a television interview. The legal status of AOD-9604 at the time of the program was uncertain: it was not explicitly listed as banned under Category S2 of the World Anti Doping Agency (WADA) code, but it had not been approved for human use by the Therapeutic Goods Administration and therefore could be considered as banned under the more general Category S0, which applied to any substances not approved for human use. The official position of WADA was that AOD-9604 had been considered a banned substance under Category S0 since 2011, and it clarified this publicly to ASADA on 22 April 2013. After considering its legal position, ASADA declared that it would not pursue any cases relating to AOD-9604 use before 22 April 2013, determining that it would be too difficult to achieve a guilty verdict for a supplement that had not yet explicitly been declared banned. Parallel to the AFL-ASADA investigation, Essendon commissioned former Telstra CEO Ziggy Switkowski to conduct a full independent review of governance and processes of the club. Switkowski's report, which was delivered on 6 May 2013, identified significant failings in governance which would later be repeated in ASADA's findings.
Single-photon emission computed tomography (SPECT) is employed in theranostics, using gamma rays emitted by a radiotracer to generate three-dimensional images of the body. SPECT imaging involves the injection of a radiotracer that emits single photons, which are detected by a gamma camera rotating around the person undergoing imaging. SPECT provides functional and anatomical information, allowing the assessment of organ structure, blood flow, and specific molecular targets. It is useful in evaluating diseases that involve altered blood flow or specific receptor expression. For example, SPECT imaging with technetium-99m (Tc-99m) radiopharmaceuticals may be able to assess myocardial perfusion and identify areas of ischemia or infarction in patients with cardiovascular diseases. SPECT imaging helps in identifying disease localization, staging, and assessing the response to therapy. Moreover, SPECT imaging is employed in targeted radionuclide therapy, where the same radiotracer used for diagnostic imaging can be used to deliver therapeutic doses of radiation to the diseased tissue.
Sources: en.wikipedia.org
In this theory, the arms and tentacles of cephalopods look similar to the head appendages of gastropods, suggesting that they might be homologous structures. Cephalopod appendages surround the mouth, so logically they could be derived from embryonic head tissues. However, the "Arms as Foot" hypothesis, proposed by Adolf Naef in 1928, has increasingly been favoured; for example, fate mapping of limb buds in the chambered nautilus indicates that limb buds originate from "foot" embryonic tissues.
Constantine's dynasty prioritised a lengthy conflict against the comparably powerful Sasanid Persia and ended in 363 with the death of his nephew Julian. The reign of the short Valentinianic dynasty, marked by wars against the Goths, religious debates, and anti-corruption campaigns, ended in the East with the death of Valens at the Battle of Adrianople in 378.
The Thyrotroph Thyroid Hormone Sensitivity Index (TTSI, also referred to as Thyrotroph T4 Resistance Index or TT4RI) was developed to enable fast screening for resistance to thyroid hormone. Somewhat similar to the TSH Index it is calculated from equilibrium values for TSH and FT4, however with a different equation.
Sources: en.wikipedia.org
It is a crystalline form of creatine that contains one water molecule per creatine molecule. The compound occurs naturally in muscle tissue and is also produced synthetically for research and consumer products. The monohydrate label describes the solid's hydration state.
Creatine monohydrate contains creatine, but the two terms are not strictly interchangeable. The monohydrate includes water in the crystal, while creatine refers to the base molecule. Other creatine forms pair the molecule with different acids or carriers.
Dietary creatine is found mainly in meat and fish. The human body also synthesizes creatine from amino acids in the liver, kidneys, and pancreas. The monohydrate powder used in products is manufactured rather than extracted directly from food.
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.