HPLC-UV 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 2026-02-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 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.
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 crystalline compound formed from creatine and one molecule of water. Creatine itself is a nitrogen-containing organic acid that occurs in vertebrate muscle and other tissues. The monohydrate designation refers to the water included in the crystal lattice, not to water added during manufacturing. Its chemical formula is commonly written as C4H9N3O2·H2O. The solid is typically a white, odorless powder with low solubility in water at room temperature. It is one of several creatine forms described in scientific and commercial literature.
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.
| 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 |
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.
Identity and purity are commonly assessed by high-performance liquid chromatography, often with ultraviolet detection, and by spectroscopic techniques such as infrared or nuclear magnetic resonance. These methods can distinguish creatine from creatinine and detect related impurities. Moisture content may be measured by Karl Fischer titration or loss on drying. Particle size, bulk density, and heavy metal limits are additional quality parameters. Not every product is tested by every method, so specifications depend on the intended use and regulatory framework.
Solid creatine monohydrate is generally stable when kept dry and protected from extremes of heat and humidity. In the presence of moisture, it can gradually convert to creatinine, a cyclic dehydration product that has little value for phosphocreatine synthesis. Elevated temperatures and acidic conditions accelerate this conversion in solution. Because the reaction is slow in cool, dry storage, typical shelf lives are measured in years rather than weeks. Packaging that limits moisture and oxygen exposure helps maintain purity.
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.
Sourcing and verification of creatine monohydrate involve both manufacturing origin and third-party testing. Industrial production commonly starts with sarcosine and cyanamide, followed by crystallization to obtain the monohydrate. Some products are derived from animal sources, while others are synthesized from non-animal precursors. Certificates of analysis report assay, heavy metals, and microbial limits. Regulations differ by country: in the United States it is sold as a dietary supplement, whereas in the European Union it falls under food supplement rules.
In solid form, creatine monohydrate is relatively stable when kept dry and away from heat. Moisture and elevated temperatures promote cyclization into creatinine, a related compound with no role in the phosphagen system. Degradation accelerates in aqueous solution, where the conversion can occur within hours to days depending on pH and temperature. Manufacturers typically recommend storage in sealed containers at room temperature, with relative humidity below 50 percent. Long-term stability data for opened containers are limited.
Kallingal married director Aashiq Abu on 1 November 2013, at the Kakkanad Registration Office, Kochi. Ahead of the ceremony, the couple donated ₹1 million towards the welfare of cancer patients at the General Hospital, Ernakulam, and ₹25,000 towards the dietary kitchen at the same hospital.
== History == Safrole was obtained from a number of plants, but especially from the sassafras tree (Sassafras albidum), which is native to North America, and from Japanese star anise (Illicium anisatum, called shikimi in Japan). In 1844, the French chemist Édouard Saint-Èvre (1817–1879) determined safrole's empirical formula. In 1869, the French chemists Édouard Grimaux (1835–1900) and J. Ruotte investigated and named safrole. They observed its reaction with bromine, suggesting the presence of an allyl group. By 1884, the German chemist Theodor Poleck (1821–1906) suggested that safrole was a derivative of benzene, to which two oxygen atoms were joined as epoxides (cyclic ethers). In 1885, the Dutch chemist Johann Frederik Eijkman (1851–1915) investigated shikimol, the essential oil that is obtained from Japanese star anise, and he found that, upon oxidation, shikimol formed piperonylic acid, whose basic structure had been determined in 1871 by the German chemist Wilhelm Rudolph Fittig (1835–1910) and his student, the American chemist Ira Remsen (1846–1927). Thus, Eijkman inferred the correct basic structure for shikimol. He also noted that shikimol and safrole had the same empirical formula and had other similar properties, and thus he suggested that they were probably identical. In 1886, Poleck showed that upon oxidation, safrole also formed piperonylic acid, and thus shikimol and safrole were indeed identical. It remained to be determined whether the molecule's C3H5 group was a propenyl group (R−CH=CH−CH3) or an allyl group (R−CH2−CH=CH2).
In two tandem Letters to the Editor (1936), Wrinch and Frank addressed the question of whether the cyclol form of the peptide group was indeed more stable than the amide form. A relatively simple calculation showed that the cyclol form is significantly less stable than the amide form. Therefore, the cyclol model would have to be abandoned unless a compensating source of energy could be identified. Initially, Frank proposed that the cyclol form might be stabilized by better interactions with the surrounding solvent; later, Wrinch and Irving Langmuir hypothesized that hydrophobic association of nonpolar sidechains provides stabilizing energy to overcome the energetic cost of the cyclol reactions. The lability of the cyclol bond was seen as an advantage of the model, since it provided a natural explanation for the properties of denaturation; reversion of cyclol bonds to their more stable amide form would open up the structure and allows those bonds to be attacked by proteases, consistent with experiment. Early studies showed that proteins denatured by pressure are often in a different state than the same proteins denatured by high temperature, which was interpreted as possibly supporting the cyclol model of denaturation. The Langmuir-Wrinch hypothesis of hydrophobic stabilization shared in the downfall of the cyclol model, owing mainly to the influence of Linus Pauling, who favored the hypothesis that protein structure was stabilized by hydrogen bonds.
By 1946, France headed the French Union. As successive governments had forbidden the sending of metropolitan troops, the French Far East Expeditionary Corps (CEFEO) was created in March 1945. The Union gathered combatants from almost all French territories made of colonies, protectorates and associated states (Algeria, Morocco, Madagascar, Senegal, Tunisia, etc.) to fight in French Indochina, which was then occupied by the Japanese. About 325,000 of the 500,000 French troops were Indochinese, almost all of whom were used in conventional units. French West Africa (Afrique Occidentale Française, AOF) was a federation of African colonies. Senegalese and other African troops were sent to fight in Indochina. Some African alumni were trained in the Infantry Instruction Center no.2 (Centre d'Instruction de l'Infanterie no.2) located in southern Vietnam. Senegalese of the Colonial Artillery fought at the siege of Dien Bien Phu. As a French colony (later a full province), French Algeria sent local troops to Indochina including several RTA (Régiment de Tirailleurs Algériens) light infantry battalions. Morocco was a French protectorate and sent troops to support the French effort in Indochina. Moroccan troops were part of light infantry RTMs (Régiment de Tirailleurs Marocains) for the "Moroccan Sharpshooters Regiment".
President Jimmy Carter, which ensured that control over the Panama Canal would pass to Panama in 1999. These treaties, as well as a new labor code that included maternity leave, collective bargaining rights, and bonus pay, made Torrijos popular in Panama despite the absence of democratic elections. Torrijos's relationship with Noriega was symbiotic; Torrijos provided the political acumen, while Noriega enforced his unpopular decisions with force, when necessary. Noriega would provide intelligence and carry out covert operations that were critical to Torrijos successfully negotiating the release of the Panama Canal from the U.S. Upon seizing power in 1968, Torrijos's government had passed legislation favorable to foreign corporations, including banks in the U.S. The following years saw a large expansion in international business activity and the influx of foreign capital, thereby giving participating corporations a stake in the continued existence of the military government. The government used its access to foreign capital to borrow extensively, fueling a rapid expansion of the state bureaucracy that contributed to the military regime's stability. Panama's borrowing peaked in 1978 when the Panama Canal treaty was being negotiated, a time at which the Carter government was particularly supportive of the Torrijos regime. The Carter administration's interest in signing a new treaty led it to largely overlook the increasing militarization of the Panamanian government, and its involvement in drug-trafficking.
Sources: en.wikipedia.org
== Natural occurrences == Prodelphinidins are one of the two sorts of tannins in grape (the other being procyanidins) being produced especially in the skin of the berry. Prodelphinidins can be found in Cistus salviifolius. Gallocatechin-(4→8)-catechin (prodelphinidin B3), gallocatechin-(4→8)-gallocatechin and catechin-(4→8)-gallocatechin can be found in the pomegranate peels. Prodelphinidin B-2 3'-O-gallate can be found in green tea leaves and prodelphinidin B-2 3,3'-di-O-gallate can be found in Myrica rubra.
cooperativity Also cooperative binding. A phenomenon observed in some enzymes, receptor proteins, and protein complexes which have multiple binding sites, whereby the binding of a ligand to one or more sites apparently increases or decreases the affinity of one or more other binding sites for other ligands. This concept highlights the sensitive nature of the chemistry that governs interactions between biomolecules: the strength and specificity of interactions between protein and ligand are influenced, sometimes substantially, by nearby interactions (often conformational changes) and by the local chemical environment in general. Cooperativity is frequently invoked to account for the non-linearity of data resulting from attempts to measure the association/dissociation constants of particular protein–protein interactions.
Bodybuilders may supplement their diets with protein for reasons of convenience, lower cost (relative to meat and fish products), ease of preparation, and to avoid the concurrent consumption of carbohydrates and fats. Additionally, some argue that bodybuilders, by virtue of their unique training and goals, require higher-than-average quantities of protein to support maximal muscle growth. While the recommended dietary allowance is much less, Harvard Medical School points out in Harvard Health Publishing that this RDA (recommended daily allowance) is “the minimum amount you need to keep from getting sick — not the specific amount you are supposed to eat every day.” Protein supplements are sold in ready-to-drink health shakes, bars, meal replacement products (see below), bites, oats, gels and powders. Protein powders are the most popular and may have flavoring added for palatability. The powder is usually mixed with water, milk or fruit juice and is generally consumed immediately before and after exercising or in place of a meal. The sources of protein are as follows and differ in protein quality depending on their amino acid profile and digestibility:
== Detecting proteins == In some applications, it is necessary to measure the total amount of protein present, rather than the levels of one particular protein. In these cases nonspecific protein assays can be used to quantitate the amount of protein in a sample. Common nonspecific protein assays include the Warburg–Christian method, Kjeldahl method, Lowry assay, and Bradford assay. Many of these rely on the spectrophotometric properties of proteins themselves or in complex with various dyes or reagents. For example, the Bradford Assay exploits the absorbance properties of Coomassie brilliant blue G-250 dye. When free of protein, the dye is red but once bound to protein it turns blue. The Kjeldahl method, in contrast, does not use any dye and is instead a titrimetric assay, sensitive to the nitrogen content in the sample, which correlates with protein content. These assays vary widely in sensitivity, specificity to proteins over other compounds in the sample, and cost.
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.
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.