creatine comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-12-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
Commercial creatine monohydrate is produced mainly by chemical synthesis rather than extraction from animal tissue. Suppliers provide a certificate of analysis listing assay, water content, and impurity limits, and some products undergo third-party testing. Verification of identity can use infrared or Raman spectroscopy alongside chromatographic methods. Storage recommendations generally call for a cool, dry place and a tightly closed container to limit moisture uptake. Open questions include how packaging, flavoring agents, and long-term storage affect the stability of finished products.
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.
Quality control for creatine monohydrate typically combines identity, assay, and impurity tests. High-performance liquid chromatography with ultraviolet detection is common for separating creatine from creatinine and related substances. Nuclear magnetic resonance and infrared spectroscopy can confirm molecular structure, while titration may assess acid-base content. Moisture content, heavy metals, residual solvents, and microbial limits are checked according to applicable standards. These tests help distinguish compliant material from powders that have degraded, been diluted, or contain manufacturing residues.
Handling practices aim to limit moisture uptake and thermal exposure. Containers should stay closed when not in use, and storage areas should avoid direct sunlight, strong heat, and high humidity. Caking can occur when powder absorbs water, even if the creatine itself has not fully degraded. Aqueous stock solutions are best prepared fresh when needed because they are less stable than the solid. Open questions include how different excipients, packaging materials, and climate conditions affect long-term stability across global supply chains.
Solid creatine monohydrate is relatively stable when kept dry and sealed, but heat and moisture accelerate its conversion to creatinine. This degradation involves intramolecular cyclization, a process that removes water and forms a less useful compound for phosphocreatine metabolism. Powder stored under cool, dry conditions can remain within specification for extended periods, though exact shelf life depends on packaging, humidity, and initial purity. Aqueous solutions degrade faster than dry powder, with pH and temperature influencing the rate. Because degradation is gradual, analytical testing is used to confirm potency at manufacture and during stability studies.
| 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 |
Commercial creatine products appear in several forms, including monohydrate, hydrochloride, citrate, nitrate, and ethyl ester. Creatine monohydrate is the most studied form and serves as a reference material in comparative research. Different forms vary in solubility, pH, and water content, but they share creatine as the active moiety after dissolution. Claims that one form is uniformly superior remain debated, and study designs often differ in population, exercise protocol, and outcome measures. Purity and hydration state are central to interpreting product labels.
Creatine monohydrate is the hydrated form of creatine, a nitrogen-containing organic acid involved in cellular energy transfer. Its molecular formula is C4H11N3O3, and it consists of creatine plus one water molecule in the crystal lattice. The anhydrous base, creatine, has the formula C4H9N3O2. The compound appears as a white, odorless, crystalline powder and is classified as a guanidine derivative. It is distinct from creatinine, a breakdown product measured in clinical chemistry.
Analytical laboratories commonly identify creatine monohydrate by high-performance liquid chromatography with ultraviolet detection, often after dissolving the sample in water or dilute acid. Ion-exchange or reversed-phase columns separate creatine from creatinine and related guanidino compounds. Nitrogen content can be checked by Kjeldahl or combustion methods, while moisture is measured by Karl Fischer titration or loss on drying. These techniques give complementary views: chromatographic purity addresses related substances, whereas moisture and elemental data confirm hydrate stoichiometry. No single test defines quality by itself; a combination is used in specifications.
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.
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.
Short-chain scorpion toxins constitute the largest group of potassium (K+) channel-blocking peptides. An important physiological role of the KCNA3 channel, also known as KV1.3, is to help maintain large electrical gradients for the sustained transport of ions such as Ca2+ that controls T lymphocyte (T cell) proliferation. Thus KV1.3 blockers could be potential immunosuppressants for the treatment of autoimmune disorders (such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis). The venom of Uroplectes lineatus is clinically important in dermatology. Several scorpion venom toxins have been investigated for medical use. Chlorotoxin from the deathstalker scorpion (Leiurus quinquestriatus); the toxin blocks small-conductance chloride channels; Maurotoxin from the venom of the Tunisian Scorpio maurus blocks potassium channels. Some antimicrobial peptides in the venom of Mesobuthus eupeus; meucin-13 and meucin-18 have extensive cytolytic effects on bacteria, fungi, and yeasts, while meucin-24 and meucin-25 selectively kill Plasmodium falciparum and inhibit the development of Plasmodium berghei, both malaria parasites, but do not harm mammalian cells.
A trial might also define one or more secondary endpoints such as progression-free-survival (PFS) that will be measured and are expected to be met. A trial might also define exploratory endpoints that are less likely to be met.
== Regulation by the photoperiod == The levels of proopiomelanocortin (pomc) are regulated indirectly in some animals by the photoperiod. It is referred to the hours of light during a day and it changes across the seasons. Its regulation depends on the pathway of thyroid hormones that is regulated directly by the photoperiod. An example are the siberian hamsters who experience physiological seasonal changes dependent on the photoperiod. During spring in this species, when there is more than 13 hours of light per day, iodothyronine deiodinase 2 (DIO2) promotes the conversion of the prohormone thyroxine (T4) to the active hormone triiodothyronine (T3) through the removal of an iodine atom on the outer ring. It allows T3 to bind to the thyroid hormone receptor (TR), which then binds to thyroid hormone response elements (TREs) in the DNA sequence. The pomc proximal promoter sequence contains two thyroid-receptor 1b (Thrb) half-sites: TCC-TGG-TGA and TCA-CCT-GGA indicating that T3 may be capable of directly regulating pomc transcription. For this reason during spring and early summer, the level of pomc increases due to the increased level of T3. However, during autumn and winter, when there is less than 13 hours of light per day, iodothyronine desiodinase 3 removes an iodine atom which converts thyroxine to the inactive reverse triiodothyronine (rT3), or which converts the active triiodothyronine to diiodothyronine (T2). Consequently, there is less T3 and it blocks the transcription of pomc, which reduces its levels during these seasons.
== Medical uses == The primary application for phentolamine is for the control of hypertensive emergencies, most notably due to pheochromocytoma. It also has usefulness in the treatment of cocaine-induced cardiovascular complications, where one would generally avoid β-blockers (e.g., metoprolol), as they can cause unopposed α-adrenergic mediated coronary vasoconstriction, worsening myocardial ischemia and hypertension. Phentolamine is not a first-line agent for this indication. Phentolamine should only be given to patients who do not fully respond to benzodiazepines, nitroglycerin, and calcium channel blockers. When given by injection, it causes blood vessels to dilate, thereby increasing blood flow. When injected into the penis (intracavernosal), it increases blood flow to the penis, which results in an erection. It may be stored in crash carts to counteract severe peripheral vasoconstriction secondary to extravasation of peripherally placed vasopressor infusions, typically of norepinephrine. Epinephrine infusions are less vasoconstrictive than norepinephrine as they primarily stimulate β receptor more than α receptors, but the effect remains dose-dependent. Phentolamine also has diagnostic and therapeutic roles in complex regional pain syndrome (CRPS). Phentolamine is marketed in the dental field as a local anesthetic reversal agent. Branded as OraVerse, it is a phentolamine mesylate injection designed to reverse the local vasoconstrictor properties used in many local anesthetics to prolong anesthesia.
Sources: en.wikipedia.org
==== Salts ==== Lysis buffer usually contains one or more salts. The function of salts in lysis buffer is to establish an ionic strength in the buffer solution. Some of the most commonly used salts are NaCl, KCl, and (NH4)2SO4. They are usually used with a concentration between 50 and 150 mM.
== Uses == PPG is used in many polyurethane formulations. Synthesis of waterborne polymers has been a feature with this substance. As the basic building block is propylene oxide, there are 3 carbons per oxygen on the backbone. This confers some degree of water miscibility though not as good as ethylene oxide-based molecules. It is used to synthesize the epoxy reactive diluent and flexibilizer, Poly(propylene glycol) diglycidyl ether. Another use of PPG is as a surfactant, wetting agent and dispersant in leather finishing. PPG is also employed as a reference and calibrant in mass spectrometry and HPLC. PPG and derivatives may be used as defoamers in drilling and other applications. It is also used as a primary ingredient in the making of paintballs. It has been evaluated as a corrosion inhibitor.
== B == B3/B4 tRNA-binding domain - B5 protein domain - BAC - back mutation - bacteria - bacterial artificial chromosome - bacteriophage - bacteriophage lambda - bacteriophage scaffolding proteins - band shift assay - base - base pair - benzoyl-CoA 2,3-dioxygenase - benzyl benzoate/disulfiram - benzyl-2-methyl-hydroxybutyrate dehydrogenase - beta-carotene 3-hydroxylase - beta-cyclopiazonate dehydrogenase - beta-glucan-transporting ATPase - beta2-adaptin C-terminal domain - binding site - biological organisation - biological process - Biomolecular gradient - Biomolecule Stretching Database - biotin - birth defect - blotting - blunt end - bone marrow transplantation - box - BP - BRCA1 - BRCA2 - Brix (database) - BSD domain - BURP domain -
It is a flat tax up to the cap, but regressive overall as it is not applied to higher incomes. The Medicare portion is also paid by employer and employee each at 1.45% and is not capped. Starting in 2013, an additional 0.9 percent more in Medicare taxes was applied to income of more than $200,000 ($250,000 for married couples filing jointly), making it a progressive tax overall. For calendar years 2011 and 2012, the employee's portion of the payroll tax was reduced to 4.2% as an economic stimulus measure; this expired for 2013. Approximately 65% percent of tax return filers pay more in payroll taxes than income taxes.
The quantitative "reading" is usually based on detection of intensity of transmitted light by spectrophotometry, which involves quantitation of transmission of some specific wavelength of light through the liquid (as well as the transparent bottom of the well in the multiple-well plate format). The sensitivity of detection depends on amplification of the signal during the analytic reactions. Since enzyme reactions are very well known amplification processes, the signal is generated by enzymes which are linked to the detection reagents in fixed proportions to allow accurate quantification, and thus the name "enzyme-linked". The analyte is also called the ligand because it will specifically bind or ligate to a detection reagent, thus ELISA falls under the bigger category of ligand binding assays. The ligand-specific binding reagent is "immobilized", i.e., usually coated and dried onto the transparent bottom and sometimes also side wall of a well (the stationary "solid phase"/"solid substrate" here as opposed to solid microparticle/beads that can be washed away), which is usually constructed as a multiple-well plate known as the "ELISA plate". Conventionally, like other forms of immunoassays, the specificity of antigen-antibody type reaction is used because it is easy to raise an antibody specifically against an antigen in bulk as a reagent. Alternatively, if the analyte itself is an antibody, its target antigen can be used as the binding reagent.
Sources: en.wikipedia.org
Acacia acinacea Acacia baileyana Acacia decurrens Acacia dealbata Acacia mearnsii Acacia drummondii Acacia elata Acacia falcata Acacia leprosa Acacia linearis Acacia melanoxylon Acacia retinodes Acacia saligna Acacia stricta Acacia verticillata Acacia visco Acacia vestita
{\displaystyle {\begin{aligned}K_{M}^{\prime }\ &{\stackrel {\mathrm {def} }{=}}\ {\frac {k_{3}}{k_{2}+k_{3}}}K_{M}={\frac {k_{3}}{k_{2}+k_{3}}}\cdot {\frac {k_{2}+k_{-1}}{k_{1}}}\\k_{cat}\ &{\stackrel {\mathrm {def} }{=}}\ {\dfrac {k_{3}k_{2}}{k_{2}+k_{3}}}\end{aligned}}}
==== Justification for intervention ==== The US and UN gave public justifications for involvement in the conflict, the most prominent being the Iraqi violation of Kuwaiti territorial integrity. In addition, the US moved to support its ally Saudi Arabia, whose importance in the region, and as a key supplier of oil, made it of considerable geopolitical importance. Shortly after the Iraqi invasion, US defense secretary Dick Cheney made the first of several visits to Saudi Arabia where King Fahd requested US military assistance. During a speech in a special joint session of the US Congress given on 11 September 1990, Bush summed up the reasons with the following remarks: "Within three days, 120,000 Iraqi troops with 850 tanks had poured into Kuwait and moved south to threaten Saudi Arabia. It was then that I decided to act to check that aggression." The Pentagon stated that satellite photos showing a buildup of Iraqi forces along the border were the source of this information, but this was later alleged to be false. A reporter for the St. Petersburg Times acquired commercial Soviet satellite images which showed nothing but empty desert. Other justifications for foreign involvement included Iraq's history of human rights abuses under Saddam. Iraq was known to possess biological weapons and chemical weapons, which Saddam had used against Iranian troops during the Iran–Iraq War and his own country's Kurdish population in the Al-Anfal campaign. Iraq was known to have a nuclear weapons program; the report about it from January 1991 was partially declassified by the CIA in May 2001.
Growth factor receptor-bound protein 14 is a protein that in humans is encoded by the GRB14 gene. The product of this gene belongs to a small family of adapter proteins that are known to interact with a number of receptor tyrosine kinases and signaling molecules. This gene encodes a growth factor receptor-binding protein that interacts with insulin receptors and insulin-like growth-factor receptors. This protein likely has an inhibitory effect on receptor tyrosine kinase signaling and, in particular, on insulin receptor signaling. This gene may play a role in signaling pathways that regulate growth and metabolism. Transcript variants have been reported for this gene, but their full-length natures have not been determined to date.
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.
Keep it in a sealed container in a cool, dry place away from direct heat and moisture. Dry powder is more stable than prepared solutions.