If you have been reading about ergogenic aid 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 2025-10-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 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.
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.
As a supplement, creatine monohydrate is studied for its effects on muscle performance and recovery. The compound is often described as an ergogenic aid, meaning it may support physical work capacity. Research typically compares it with placebo or other forms, such as citrate or nitrate, under controlled conditions. Questions remain about the optimal dose and long-term effects in different populations, and findings are not uniform across all studies. The monohydrate form remains the most extensively tested.
| 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 |
Most RTGs use 238Pu, which decays with a half-life of 87.7 years. RTGs using this material therefore diminish in power output by a factor of 1 – (1/2)1/87.7, or 0.787%, per year. One example is the MHW-RTG used by the Voyager probes. In the year 2000, 23 years after production, the radioactive material inside the RTG had decreased in power by 16.6%, i.e. providing 83.4% of its initial output; starting with a capacity of 470 W, after this length of time it would have a capacity of only 392 W. A related loss of power in the Voyager RTGs is the degrading properties of the bi-metallic thermocouples used to convert thermal energy into electrical energy; the RTGs were working at about 67% of their total original capacity instead of the expected 83.4%. By the beginning of 2001, the power generated by the Voyager RTGs had dropped to 315 W for Voyager 1 and to 319 W for Voyager 2. By 2022, these numbers had dropped to around 220 W. NASA has developed a multi-mission radioisotope thermoelectric generator (MMRTG) in which the thermocouples would be made of skutterudite, a cobalt arsenide (CoAs3), which can function with a smaller temperature difference than the current tellurium-based designs. This would mean that an otherwise similar RTG would generate 25% more power at the beginning of a mission and at least 50% more after seventeen years. NASA hopes to use the design on the next New Frontiers mission.
The epoxy cycle of ethylene oxide is an almost regular triangle with bond angles of about 60° and a significant angular strain corresponding to the energy of 105 kJ/mol. For comparison, in alcohols the C–O–H angle is about 110°; in ethers, the C–O–C angle is 120°. The moment of inertia about each of the principal axes are IA = 32.921×10−40 g·cm2, IB = 37.926×10−40 g·cm2 and IC = 59.510×10−40 g·cm2. The relative instability of the carbon-oxygen bonds in the molecule is revealed by the comparison in the table of the energy required to break two C–O bonds in the ethylene oxide or one C–O bond in ethanol and dimethyl ether:
=== Insect mouthparts === Insect mouthparts show many examples of convergent evolution. The mouthparts of different insect groups consist of a set of homologous organs, specialised for the dietary intake of that insect group. Convergent evolution of many groups of insects led from original biting-chewing mouthparts to different, more specialised, derived function types. These include, for example, the proboscis of flower-visiting insects such as bees and flower beetles, or the biting-sucking mouthparts of blood-sucking insects such as fleas and mosquitos.
Sources: en.wikipedia.org
=== Homo floresiensis === Recent publications have proposed that Homo floresiensis represented a population with widespread Laron syndrome, based upon the many similarities of skeletal remains found in Indonesia with LS. This is only one of several competing hypotheses, and has received criticism as insufficient to explain the "range features observed in H. floresiensis". Similar postulates have been proposed regarding the Pygmies of Central Africa.
The council is based at County Hall at Aykley Heads in the northern suburbs of the city of Durham. The building was purpose-built for the council and was completed in 1963. When first created the council met at the courthouse on Old Elvet, which at the time was known as Shire Hall. A few years after its creation the council decided to build its own headquarters on a site nearby, also on Old Elvet, which was also given the name Shire Hall. The new building was completed in 1898, after which the old Shire Hall became known as the Assizes Court, and since 1971 as Durham Crown Court. The council has announced plans to move to the Rivergreen building, also in the Aykley Heads area of Durham, in 2025, with the intention that County Hall would then be redeveloped.
Surgery to remove the prostate is called prostatectomy, and is usually done as a treatment for cancer limited to the prostate, or for prostatic enlargement. When it is done, it may be done as open surgery or as laparoscopic (keyhole) surgery. These are done under general anaesthetic. Usually the procedure for cancer is a radical prostatectomy, which means that the seminal vesicles are removed and the vasa deferentia are also tied off. Part of the prostate can also be removed from within the urethra, called transurethral resection of the prostate (TURP). Open surgery may involve a cut that is made in the perineum, or via an approach that involves a cut down the midline from the belly button to the pubic bone. Open surgery may be preferred if there is a suspicion that lymph nodes are involved and they need to be removed or biopsied during a procedure. A perineal approach will not involve lymph node removal and may result in less pain and a faster recovery following an operation. A TURP procedure uses a tube inserted into the urethra via the penis and some form of heat, electricity or laser to remove prostate tissue. The whole prostate can be removed. Complications that might develop because of surgery include urinary incontinence and erectile dysfunction because of damage to nerves during the operation, particularly if a cancer is very close to nerves. Ejaculation of semen will not occur during orgasm if the vasa deferentia are tied off and seminal vesicles removed, such as during a radical prosatectomy. This will mean a man becomes infertile.
=== Chemotherapy and other drug therapies === The role of chemotherapy in DIPG remains unclear. Studies have shown little improvement in survival, although efforts (see below) through the Children's Oncology Group (COG), Paediatric Brain Tumour Consortium (PBTC), and others are underway to explore further the use of chemotherapy and other drugs. Drugs that increase the effect of radiotherapy (radiosensitizers) have shown no added benefit, but promising new agents are under investigation. Immunotherapy with beta-interferon and immune checkpoint inhibitors has also had little effect in trials. Neoepitope specific peptide vaccines targeting the clonal driver mutation H3 K27M have been shown to elicit cytotoxic T-cell and T-helper cell responses in patients with diffuse midline glioma. Intensive or high-dose chemotherapy with autologous bone marrow transplantation or peripheral blood stem cell rescue has not demonstrated any effectiveness in brain stem gliomas. Future clinical trials may involve medicines designed to interfere with cellular pathways (signal transfer inhibitors), or other approaches that alter the tumor or its environment.
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.
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.