If you have been reading about phosphocreatine and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-01-02. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 compound formed from creatine and one molecule of water. Its systematic name is N-(aminoiminomethyl)-N-methylglycine monohydrate, and it appears as a white, odorless powder with limited solubility in water. The monohydrate is the most common solid form used in research and commercial products because it is stable under dry conditions. The anhydrous form lacks the water of crystallization and differs slightly in molar mass. Both forms participate in the same biochemical reactions once dissolved.
In the body, creatine is synthesized from the amino acids arginine, glycine, and methionine, primarily in the liver and kidneys. It is transported to muscle and other tissues, where it is phosphorylated to phosphocreatine by creatine kinase. This phosphagen system provides a rapid source of adenosine triphosphate during short, intense contractions. Dietary creatine comes mainly from meat and fish, and the body's total pool is influenced by both synthesis and intake.
| 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 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.
Asparagine endopeptidase (AEP, mammalian legumain, δ-secretase; EC 3.4.22.34) is a proteolytic enzyme from C13 peptidase family which hydrolyses a peptide bond using the thiol group of a cysteine residue as a nucleophile (hence also called cysteine protease). It is also known as asparaginyl endopeptidase, citvac, proteinase B, hemoglobinase, PRSC1 gene product or LGMN (Homo sapiens), vicilin peptidohydrolase and bean endopeptidase. In humans it is encoded by the LGMN gene (previous symbol PRSC1). It hydrolyzes substrates at the C-terminus of asparagine residues. Discovered in 1996 in beans, its homologues have been identified in plants, protozoa, vertebrates, and helminths. The enzyme has been implicated in several human diseases such as cancer, atherosclerosis and inflammation . It can be detected in spleen, liver, brain, testis tissue and heart and the protein is mostly localised to lysosomes and endosomes. It is also interesting that AEP is activated in age-dependent manner.
is the observed value. An error of a measurement is an inverse measure of accurate measurement (i.e., smaller the error greater the accuracy of the measurement). Errors can be expressed relatively. Given the relative error (
EMP, also known as estradiol 3-normustine 17β-phosphate or as estradiol 3-(bis(2-chloroethyl)carbamate) 17β-(dihydrogen phosphate), is a synthetic estrane steroid and a derivative of estradiol. It is an estrogen ester; specifically, EMP is a diester of estradiol with a C3 normustine (nitrogen mustard–carbamate moiety) ester and a C17β phosphate ester. EMP is provided as the sodium or meglumine salt. EMP is similar as a compound to other estradiol esters such as estradiol sulfate and estradiol valerate, but differs in the presence of its nitrogen mustard ester moiety. Antineoplastic agents related to EMP, although none of them were marketed, include alestramustine, atrimustine, cytestrol acetate, estradiol mustard, ICI-85966, and phenestrol. Due to its hydrophilic phosphate ester moiety, EMP is a readily water-soluble compound. This is in contrast to most other estradiol esters, which are fatty acid esters and lipophilic compounds that are not particularly soluble in water. Unlike EMP, estramustine is highly lipophilic, practically insoluble in water, and non-ionizable. The phosphate ester of EMP was incorporated into the molecule in order to increase its water solubility and allow for intravenous administration. The molecular weight of EMP sodium is 564.3 g/mol, of EMP meglumine is 715.6 g/mol, of EMP is 520.4 g/mol, of estramustine is 440.4 g/mol, and of estradiol is 272.4 g/mol.
Sources: en.wikipedia.org
== Pharmacokinetics == Depending on the surface area and depth of the wound, bromelain blood serum concentrations of no more than 40 μg/ml are expected, with peak concentrations reached after 2 to 4 hours. The terminal half-life varied between 8.5 and 19.9 hours in studies. These data have been obtained from 15 patients with comparatively shallow wounds.
In December 2022, the company announced initial phase 1 clinical trial results for its flu vaccine patch. In 2023, Vaxess and AstraZeneca announced the development of a skin patch for mRNA vaccines focused on pandemic flu. In May 2024, Vaxess announced $12 million in funding and named Rachel Sha as CEO of the company. In May 2025, Vaxess announced $9 million in funding to advance its work in GLP-1, and . In June, the company presented new clinical data on the capability of its drug delivery patch to deliver semaglutide.
With the Regents of the University of California still holding their (earlier) view that their university's Charter precluded any commercial activity, the Regents and Robertson eventually came to the extraordinary (at the time) arrangement (UC.5) of creating an external-to-the-university entity to manage the patent and "apply any unexpended balance of such proceeds, profits or returns to research work in Medicine and preferably in the Physiology, Chemistry and Pathology of Growth either under the auspices of the University of California or otherwise ... [or] such research work be conducted in part in Australia, either under the auspices of some institution of learning there or otherwise". Robertson and five others from the University of California formed the entity's first Board of Directors: Herbert McLean Evans (Professor of Anatomy), Frederick Parker Gay (Professor of Pathology), T. Brailsford Robertson (Professor of Biochemistry and Pharmacology), Carl Louis August Schmidt (Research Assistant in Pathology), and George Hoyt Whipple (Director of the Hooper Foundation for Medical Research and Professor of Research Medicine); and, once the Board of Directors had been appointed, the university granted a five year exclusive license in September 1917 to the H. K. Mulford Company "to manufacture and sell the compound known as Tethelin at its factory in the City of Philadelphia, State of Pennsylvania". "In 1923, by the end of Mulford's five-year contract, the university's royalties on sales of tethelin amounted to only $272.47" (CW.1, p. 35).
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.
It is a compound made of creatine bound to one water molecule. It appears as a white crystalline powder and is the most common solid form of creatine used in research and supplements.