Everything below concerns Moisture content. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | 15–25 °C | Protect from moisture, heat, and direct sunlight |
| Analytical method | HPLC with UV or RI detection | Separates creatine from creatinine and related impurities |
| Water content | About 12.1% w/w | Theoretical value for the monohydrate crystal |
| Degradation product | Creatinine | Formed by cyclization, especially in aqueous solution |
| Common assay specification | 98.0–102.0% | Range depends on the testing method and monograph |
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.
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.
Storage recommendations generally emphasize a cool, dry place away from direct sunlight and strong oxidizers. Sealed containers limit humidity exchange, which helps prevent clumping and gradual conversion to creatinine. Long-term stability studies usually monitor appearance, moisture, and purity at intervals under defined temperature and humidity conditions. Accelerated tests at elevated temperature can reveal degradation pathways, but they do not perfectly predict room-temperature shelf life. Questions remain about how much creatinine formation is acceptable in different product categories and how packaging choices affect that rate over time.
Commercial creatine monohydrate is typically manufactured through chemical synthesis, often starting from sarcosine and cyanamide. The resulting material is crystallized, washed, and dried to a specified hydrate content. Finished lots are tested for identity, purity, moisture, and heavy metals before release. Because the compound can cyclize to creatinine under heat or prolonged storage in solution, manufacturers control temperature and humidity during processing. The solid itself is relatively stable when kept dry and sealed, but moisture uptake can cause caking and complicate accurate assay.
== Predictive aspects == In a longitudinal evaluation of the NHANES study, a large sample of the general US population, over 10 years, reduced SPINA-DI, calculated as the product of SPINA-GBeta times SPINA-GR, significantly predicted all-cause mortality.
It is believed that the diverse range of structures formed by actin enabling it to fulfill such a large range of functions is regulated through the binding of tropomyosin along the filaments. A cell's ability to dynamically form microfilaments provides the scaffolding that allows it to rapidly remodel itself in response to its environment or to the organism's internal signals, for example, to increase cell membrane absorption or increase cell adhesion in order to form cell tissue. Other enzymes or organelles such as cilia can be anchored to this scaffolding in order to control the deformation of the external cell membrane, which allows endocytosis and cytokinesis. It can also produce movement either by itself or with the help of molecular motors. Actin therefore contributes to processes such as the intracellular transport of vesicles and organelles as well as muscular contraction and cellular migration. It therefore plays an important role in embryogenesis, the healing of wounds, and the invasivity of cancer cells. The evolutionary origin of actin can be traced to prokaryotic cells, which have equivalent proteins. Actin homologs from prokaryotes and archaea polymerize into different helical or linear filaments consisting of one or multiple strands. However the in-strand contacts and nucleotide binding sites are preserved in prokaryotes and in archaea. Lastly, actin plays an important role in the control of gene expression.
=== SEC-TS === Size exclusion chromatography can be used directly to access protein stability in the presence or absence of ligands. Samples of purified protein are heated in a water bath or thermocycler, cooled, centrifuged to remove aggregated proteins, and run on an analytical HPLC. As the melting temperature is reached and protein precipitates or aggregates, peak height decreases and void peak height increases. This can be used to identify ligands and inhibitors, and optimize purification conditions. While of lower throughput than FSEC-TS, requiring large amounts of purified protein, SEC-TS avoids any influence of the fluorescent tag on apparent protein stability.
=== Step-growth polymerization === Step-growth polymerization involves two monomers with bi- or multifunctionality to form polymer chains. Many polymers are synthesized via step-growth polymerization and include polyesters, polyamides, and polyurethanes. A sub-class of step-growth polymerization is condensation polymerization.
Sources: en.wikipedia.org
== Humphreys' influence == Humphreys influenced generations of sociologists and other social and behavioral scientists in complex ways. He is often studied in research methods classes for the ethical questions that his works raised. However, Earl Babbie, who writes about sociological research methods, notes that the controversy about "sociological snoopers" and research ethics was likely the result of societal homophobia and disgust with the research topic, and not due to real problems with research methods. Schacht credits Humphreys with pioneering research on impersonal sex, now a common topic of research and advocacy in the context of HIV/AIDS. Tewksbury writes about the multiple studies that were inspired by Humphrey's work, calling his work a rich legacy for future sex researchers. According to Brekhus, Humphrey's contribution to sociological theory, in particular to the development of the concept of identity politics, is often overlooked, but should be hailed as an important forerunner to modern queer theory. Nardi also lauds Humphreys' theoretical work, especially his concept of the breastplate of righteousness. Humphreys developed this idea to explain the apparent contradiction of presumably straight, married men holding a public conservative stance against homosexuality, yet engaging in impersonal sex with men in public settings. In 2003, the presidential session at the Society for the Study of Social Problems (SSSP) was devoted to honoring Humphrey's pioneering work on sexuality.
Microcapsules that respond to magnetic and photo stimuli, such as these constructed of graphene oxide, are useful for biomedical applications that require in vivo, contact-free manipulation of cellular structures such as stem cells.
where SCr is serum creatinine (mg/dL), k is 0.7 for females and 0.9 for males, a is −0.241 for females and −0.302 for males, min indicates the minimum of SCr/k or 1, and max indicates the maximum of SCr/k or 1. As separate equations for different populations: For creatinine (IDMS calibrated) in mg/dL:
=== Republic of Egypt (from 1953) === King Hussein of Jordan, 1955 Marshal Josip Broz Tito, President of the Federal People's Republic of Yugoslavia, 1956 Prof. Amintore Fanfani, Prime Minister and ad-interim Minister of Foreign Affairs of the Republic of Italy, 1959 Yuri Gagarin, Soviet cosmonaut, 1961 Taha Hussein, Egyptian writer, 1965 Umm kulthum, Egyptian singer and actress, 1965 Mohammed Abdel Wahab, Egyptian singer and composer, 1965 President Jimmy Carter, President of the United States, 1979 Emperor Akihito of Japan Emperor Amha Selassie of Ethiopia Mohammed Burhanuddin, 52nd Da'i al-Mutlaq of the Dawoodi Bohra, 1978 King Bhumibol Adulyadej of Thailand Mohamed ElBaradei, former director general of the International Atomic Energy Agency (IAEA) Queen Elizabeth II, 1975 Birendra Bir Bikram shah Dev, King of Nepal, 1974 Mohammad Reza Pahlavi, Shah of Iran, 1975 Hassaballah El Kafrawy, Egyptian former Minister of Housing Pengiran Anak Haji Mohamed Yusof, prince consort and cheteria of Brunei, 1984 Naguib Mahfouz, Egyptian writer, 1988 King Fahd bin Abdulaziz Al Saud of Saudi Arabia, 1989 Pierre Gemayel, founder of the Lebanese Phalange Emperor Haile Selassie of Ethiopia King Hamad bin Isa Al Khalifa of Bahrain, 2016 King Idris of Libya (Grand Cordon) Ekmeleddin İhsanoğlu, Turkish academic, diplomat and former Secretary-General of the Organisation of Islamic Cooperation (OIC) Émile Lahoud, President of Lebanon, 2000 Makarios III, former president of Cyprus Nelson Mandela, President of South Africa Adly Mansour, former Chief Justice of the Supreme Constitutional Court and former acting President of Egypt King Mohammed VI of Morocco Muhammad Naguib, First President of Egypt Nursultan Nazarbayev, President of Kazakhstan Antonín Novotný, President of Czechoslovakia Sultan Qaboos bin Said al Said of Oman, 1976 Ziaur Rahman, President of Bangladesh Heinrich Rau, East German politician (Grand Cordon), 1961 King Saud bin Abdulaziz Al Saud of Saudi Arabia, 1954 King Norodom Sihanouk of Cambodia William E. Simon, U.S. Secretary of the Treasury Suharto, President of Indonesia Field Marshal Mohamed Hussein Tantawi, former chairman of the Supreme Council of the Armed Forces of Egypt, 2012 Walter Ulbricht, President of East Germany, 1965 George Vasiliou, former president of Cyprus Sir Magdi Habib Yacoub, Egyptian professor of Cardiothoracic Surgery Professor Ahmed Zewail, Egyptian scientist Katerina Sakellaropoulou, President of Greece, 2020 Salva Kiir Mayardit, President of South Sudan, 2020 Haitham bin Tariq, Sultan of Oman, 2023 Narendra Modi, Prime Minister of India, 2023 Mufaddal Saifuddin, 53rd Da'i al-Mutlaq of the Dawoodi Bohras, 2023 Mishal Al-Ahmad Al-Jaber Al-Sabah, Emir of Kuwait, 2024 King Frederik X, King of Denmark, 2024 King Felipe VI, King of Spain, 2025 Donald Trump, President of the United States, 2025
== Chemical synthesis == The industrial synthesis combines acrolein, methanethiol, and cyanide, which affords the hydantoin. Racemic methionine can also be synthesized from diethyl sodium phthalimidomalonate by alkylation with chloroethylmethylsulfide (ClCH2CH2SCH3) followed by hydrolysis and decarboxylation. Also see Methanol.
Sources: en.wikipedia.org
Purity testing often uses high-performance liquid chromatography to measure creatine and creatinine. Water content can be checked by Karl Fischer titration. Additional tests may cover heavy metals, residual solvents, and microbial contamination.
In solution, creatine can cyclize spontaneously to creatinine. Heat and certain pH conditions increase the rate of this conversion. Dry crystalline material is more stable because the reaction requires water.
Typical storage is in a sealed container at room temperature, away from moisture and direct heat. These conditions reduce caking and slow degradation. Liquid products require more careful handling because creatine is less stable in water.
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.