This is a working overview of creatinine, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
Manufacturing processes can leave trace amounts of dicyandiamide, creatinine, or residual solvents, depending on the synthetic route and purification steps. Heavy metals, arsenic, and microbial contamination are also monitored for food or pharmaceutical grades. Particle size distribution can affect dissolution behavior and blending uniformity, so it may be specified for certain applications. Analytical results are reported on a dry basis or as-is basis, and the difference matters when comparing certificates of analysis. Open questions remain about how minor impurities influence long-term stability under varied storage conditions.
Stability studies typically examine the effects of temperature, humidity, and light on creatine monohydrate. Sealed containers stored in cool, dry conditions help limit moisture uptake and hydrolysis. Elevated temperature and high relative humidity can accelerate conversion to creatinine, especially in aqueous solutions. In solid dosage forms, excipients and processing steps may also affect stability. Published stability data are not fully consistent across studies because test conditions and analytical methods vary.
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.
| Property | Value | Notes |
|---|---|---|
| Assay method | HPLC with UV detection | Commonly used for content and purity |
| Water content | Karl Fischer titration | Measures total water including hydration |
| Identity test | FTIR or NMR spectroscopy | Confirms chemical structure |
| Common impurities | Dicyandiamide, creatinine | Process-related or degradation markers |
| Storage condition | Dry, sealed, 15–25 °C | Protect from moisture and heat |
Analytical methods for creatine monohydrate focus on identity, purity, and degradation products. High-performance liquid chromatography with ultraviolet detection is common, often at a wavelength near 210 nanometers. Titration and nuclear magnetic resonance spectroscopy can also quantify the parent compound. Pharmacopeial monographs specify tests for appearance, solubility, water content, and related substances, including creatinine. Purity values above 99 percent are typical for pharmaceutical-grade material, though supplement-grade products vary. Independent verification can detect label discrepancies.
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.
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.
The "Cave with the Ring-Bearing Doves" (Cave 123) had a type of "central pillar" structure, with niche and circumambulating corridor, but with a very uncharacteristic cubic main cella crowned by a magnificent dome decorated with divinities. The main cella forms a square vestibule or main hall (3.42 x 3.42 meters; 12 x 12 feet) in front of the pillar forming the back wall, the vestibule being surmounted by a decorated dome. The prototype for the dome decorated with standing Buddhist deities is to be found in Group C of the caves at Bamiyan. It can also be seen in some other caves in the region, such as in Kumtura. The cave is named after a pattern of "flying geese holding a wreath" (or ring). This pattern is also known from Cave 69, which is dated to 625–647 CE because of the depiction and inscription of a historically identified king. Because of this marker, Cave 123 may be dated to the same period. Two monumental Buddha images occupy the sides of the main cella. They have full-body "mandorla" halos filled with a multitude of sitting or standing Buddhas. These monumental images represent the second Great Miracle of the Sakyamuni Buddha at Shravasti. The myriads of Buddhas emanating from him, each standing on a lotus, are a result of his deep meditation at Shravasti, as recounted in the Divyavadana. This understanding of the Great Miracle is most prominent among the Sarvastivadin and the Mulasarvastivadin. The two monumental Buddhas are surrounded by attendants, some light-skinned and some dark-skinned, and a Vajrapani.
Astatine was first produced by bombarding bismuth-209 with energetic alpha particles, and this is still the major route used to create the relatively long-lived isotopes astatine-209 through astatine-211. Astatine is only produced in minuscule quantities, with modern techniques allowing production runs of up to 6.6 gigabecquerels (about 86 nanograms or 2.47×1014 atoms). Synthesis of greater quantities of astatine using this method is constrained by the limited availability of suitable cyclotrons and the prospect of melting the target. Solvent radiolysis due to the cumulative effect of astatine decay is a related problem. With cryogenic technology, microgram quantities of astatine might be able to be generated via proton irradiation of thorium or uranium to yield radon-211, in turn decaying to astatine-211. Contamination with astatine-210 is expected to be a drawback of this method. The most important isotope is astatine-211, the only one in commercial use. To produce the bismuth target, the metal is sputtered onto a gold, copper, or aluminium surface at 50 to 100 milligrams per square centimeter. Bismuth oxide can be used instead; this is forcibly fused with a copper plate. The target is kept under a chemically neutral nitrogen atmosphere, and is cooled with water to prevent premature astatine vaporization. In a particle accelerator, such as a cyclotron, alpha particles are collided with the bismuth. Even though only one bismuth isotope is used (bismuth-209), the reaction may occur in three possible ways, producing astatine-209, astatine-210, or astatine-211.
=== Analogues === Close analogues of phenelzine include the amphetamine and hydrazine derivatives pheniprazine (α-methylphenelzine; the corresponding amphetamine analogue) and metfendrazine (α,N-dimethylphenelzine; the corresponding methamphetamine analogue), among others. Other analogues of phenelzine are its deuterated isotopologues α,α-dideuterophenelzine (d2-phenelzine) and α,α,β,β-tetradeuterophenelzine (d4-phenelzine), which show strongly potentiated pharmacological activity compared to phenelzine.
Sources: en.wikipedia.org
=== In vitro approaches === Intrinsically unfolded proteins, once purified, can be identified by various experimental methods. The primary method to obtain information on disordered regions of a protein is NMR spectroscopy. The lack of electron density in X-ray crystallographic studies may also be a sign of disorder. Folded proteins have a high density (partial specific volume of 0.72-0.74 mL/g) and commensurately small radius of gyration. Hence, unfolded proteins can be detected by methods that are sensitive to molecular size, density or hydrodynamic drag, such as size exclusion chromatography, analytical ultracentrifugation, small angle X-ray scattering (SAXS), and measurements of the diffusion constant. Unfolded proteins are also characterized by their lack of secondary structure, as assessed by far-UV (170–250 nm) circular dichroism (esp. a pronounced minimum at ~200 nm) or infrared spectroscopy. Unfolded proteins also have exposed backbone peptide groups exposed to solvent, so that they are readily cleaved by proteases, undergo rapid hydrogen-deuterium exchange and exhibit a small dispersion (<1 ppm) in their 1H amide chemical shifts as measured by NMR. (Folded proteins typically show dispersions as large as 5 ppm for the amide protons.) Recently, new methods including fast parallel proteolysis (FASTpp) have been introduced, which allow to determine the fraction folded/disordered without the need for purification.
== Calcium-deficient hydroxyapatite == Calcium-deficient (non-stoichiometric) hydroxyapatite, Ca10−x(PO4)6−x(HPO4)x(OH)2−x (where x is between 0 and 1) has a Ca/P ratio between 1.67 and 1.5. The Ca/P ratio is often used in the discussion of calcium phosphate phases. Stoichiometric apatite Ca10(PO4)6(OH)2 has a Ca/P ratio of 10:6 normally expressed as 1.67. The non-stoichiometric phases have the hydroxyapatite structure with cation vacancies (Ca2+) and anion (OH−) vacancies. The sites occupied solely by phosphate anions in stoichiometric hydroxyapatite, are occupied by phosphate or hydrogen phosphate, HPO2−4, anions. These calcium-deficient phases can be prepared by precipitation from a mixture of calcium nitrate and diammonium phosphate with the desired Ca/P ratio, for example, to make a sample with a Ca/P ratio of 1.6:
=== Sulfur insertion into unreactive C-H bonds === Sulfurtransferases are a small subset of radical SAM enzymes. Two well-known examples are BioB and LipA which are independently responsible for biotin synthesis and lipoic acid metabolism, respectively.
==== False information and fines ==== During the elections, Jornal da Band released false polling that showed Melo in the lead against d'Ávila. Melo's campaign would later post their findings onto his Instagram account. Jornal da Band would later correct the polling data and Melo's campaign removed the post from social media. He was later condemned by electoral courts under the Brazilian Election Justice and was made to pay 106,000 reais for spreading false information. The judge that made the decision made the call to forward the case to the Federal Police for a criminal investigation. Melo and Gomes were fined again through the Election Justice for 41,900 reais for a series of irregularities in the campaign's finances, including the use of provisions to print religiously styled pamphlets that displayed him appearing alongside city council candidates from the PTB, a party that had not formally become a member of his coalition. Allies of Melo also went around the city to spread rumors that if d'Ávila was elected, that she would close the city's churches and force people to eat dog meat.
Sources: en.wikipedia.org
=== Phosphorus nuclear magnetic resonance === Phosphorus nuclear magnetic resonance (31PNMR) is a type of nuclear magnetic resonance technique that utilizes 31phosphorus instead of deuterium. 31P is dependent upon changes in the mobility and diffusion of a molecule. It also applies an external magnetic field to analyze the alignment of the paramagnetic compounds and uses changes in the positive or negative magnetic spin values to detect these changes. It is useful in distinguishing between lamellar and hexagonal phases that contain phosphate groups based on their distinct patterns and signals. A disadvantage to this technique is that it is limited to phospholipids.
=== Financial operations === It is difficult to trace the financial movements of the CJNG given its multifaceted and illegal nature, but some estimate their assets to be worth over $20 billion. The main source of revenue for the cartel is the trade of illegal drugs, which is extremely profitable with markets in the United States and the EU. Money laundering through real estate investments, front businesses, cryptocurrency, and offshore financial institutes help the CJNG to disguise and distribute large sums. Key to the cartel's large revenue gains is its rapid geographic expansion; the CJNG has captured key ports of entry along the Gulf and the Pacific since its rise in 2009, increasing its ability to extract key elements of the illegal drug supply chain. Although the CJNG generates significant revenues from narco-trafficking, the takeover of non-drug related industries, which often capitalize on the expertise of local gangs who have been absorbed by the CJNG, help the cartel to create more immediate revenues and establish regional control. A variety of peripheral operations, such as extortion of tortilla, avocado, lime, and chicken industries, as well as fuel theft and counterfeit time-share dealings, help the CJNG to accumulate revenue to fund the trafficking of illegal drugs like fentanyl, cocaine, and methamphetamine into the United States. The cartel relies on the extortion of agricultural farms, recently profiting greatly off of Mexico's 'green gold', avocados.
== Notable accomplishments == She was a Fellow of the National Academy of Sciences. She also won the A.V. Rama Rao Foundation Award, the Jawaharlal Nehru Birth Centenary Visiting Fellowship, Third World Academy of Sciences Award in Chemistry in 1999 for her work in bio-organic chemistry, and the Sukh Dev Endowment Lectureship. At the time of her death, she was the most prolific organic chemist in India, having, in the last five years, a dozen publications in The Journal of the American Chemical Society, six in the Journal of Organic Chemistry and dozens in others. Her monumental contribution to the Accounts of Chemical Research was published, as well as many other papers, posthumously. She was elected Fellow of the Indian Academy of Sciences, Indian National Science Academy and the recipient of many honors the last of which was The Third World Academy of Sciences Award in chemistry for her outstanding contributions to bio-organic chemistry, particularly supramolecular assemblies, molecular design, chemical simulation of key biological processes, synthesis of functional hybrid peptides and synthesis of nanotubes, in 1999.
Sources: en.wikipedia.org
Purity is commonly assessed by HPLC, which separates creatine from related compounds such as creatinine. Water content is measured separately by Karl Fischer titration. Together these results help calculate the actual creatine content in a sample.
Creatine monohydrate contains water as part of its crystal structure, so some water is expected. Excess moisture can promote clumping, hydrolysis, or microbial growth. Karl Fischer titration measures total water and helps distinguish expected hydration from residual moisture.
Dicyandiamide, creatinine, and related nitrogenous compounds are common markers. Their levels are controlled by manufacturing processes and product specifications. Heavy metals and microbial limits may also be tested depending on the intended grade.
A sealed container at room temperature, away from moisture and direct heat, is suitable for most solid material. Keeping the lid closed limits water uptake and caking. Long-term storage in a refrigerator is not necessary if the powder remains dry.