If you have been reading about HPLC-UV 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 2026-01-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C4H9N3O2·H2O | Monohydrate form; anhydrous is C4H9N3O2 |
| Molar mass | 149.15 g/mol | For the monohydrate |
| Appearance | White crystalline powder | Odorless, slightly bitter taste |
| Solubility in water | ~13 g/L at 25 °C | Poorly soluble; increases with temperature |
| CAS Registry Number | 6020-87-7 | For creatine monohydrate |
Creatine monohydrate is a crystalline compound formed when one molecule of creatine associates with one molecule of water in the solid lattice. Its molecular formula is C4H11N3O3, and its molar mass is about 149.15 grams per mole. The material appears as a white, odorless powder that dissolves sparingly in water at room temperature. The monohydrate designation distinguishes it from anhydrous creatine, which lacks the bound water and has a lower molar mass. This hydrate is the most common commercial form of creatine used in nutritional and research settings.
Creatine is synthesized endogenously in humans, mainly in the liver, kidney, and pancreas, from the amino acids arginine, glycine, and methionine. Skeletal muscle stores much of the body's creatine, where it participates in the phosphocreatine system that buffers adenosine triphosphate during short, intense contractions. Dietary sources include meat and fish, so omnivorous diets provide additional creatine beyond endogenous production. Supplemental creatine monohydrate supplies the same molecule found in food and tissues, not a distinct drug or hormone. Research interest centers on its role in cellular energy transfer and its effects on muscle and other tissues.
Several creatine forms are sold, including monohydrate, anhydrous, hydrochloride, nitrate, citrate, and blends. Once dissolved, these forms deliver creatine, but they differ in molar mass, solubility, counterions, and water content. Creatine monohydrate has the largest body of published human data among these forms. Questions remain about whether any alternative form offers meaningful advantages in absorption, tolerability, or tissue uptake under practical conditions. The hydrate form's lower creatine content by mass is a compositional fact, not a statement about effectiveness.
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.
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.
Creatine monohydrate is a hydrated form of creatine, a nitrogen-containing compound involved in cellular energy metabolism. Its molecular formula is C4H9N3O2·H2O, with a molar mass around 149.15 g/mol. The monohydrate is the most common solid form used in research and commercial settings because it crystallizes readily and remains stable under ordinary conditions. The term monohydrate indicates one water molecule per creatine molecule in the crystal lattice. It appears as a white crystalline powder with low odor.
In the body, creatine is synthesized from arginine, glycine, and methionine, mainly in the liver and kidneys, and is also obtained from foods such as meat and fish. About 95% of body creatine is stored in skeletal muscle, where a fraction is phosphorylated to phosphocreatine. Phosphocreatine serves as a rapid reserve of high-energy phosphate for short bursts of ATP regeneration. The monohydrate form supplies creatine after dissolution and absorption, but it is not itself the active phosphorylated species.
Ground substance is an amorphous gel-like substance in the extracellular space of animals that contains all components of the extracellular matrix (ECM) except for fibrous materials such as collagen and elastin. Ground substance is active in the development, movement, and proliferation of tissues, as well as their metabolism. Additionally, cells use it for support, water storage, binding, and a medium for intercellular exchange (especially between blood cells and other types of cells). Ground substance provides lubrication for collagen fibers. The components of the ground substance vary depending on the tissue. Ground substance is primarily composed of water and large organic molecules, such as glycosaminoglycans (GAGs), proteoglycans, and glycoproteins. GAGs are polysaccharides that trap water, giving the ground substance a gel-like texture. Important GAGs found in ground substance include hyaluronic acid, heparan sulfate, dermatan sulfate, and chondroitin sulfate. With the exception of hyaluronic acid, GAGs are bound to proteins called proteoglycans. Glycoproteins are proteins that attach components of the ground substance to one another and to the surfaces of cells. Components of the ground substance are secreted by fibroblasts. Usually it is not visible on slides, because it is lost during staining in the preparation process. Link proteins such as vinculin, spectrin and actomyosin stabilize the proteoglycans and organize elastic fibers in the ECM. Changes in the density of ground substance can allow collagen fibers to form aberrant cross-links.
Phencyclidine or phenylcyclohexyl piperidine (PCP), also known in its use as a street drug as angel dust among other names, is a dissociative anesthetic mainly used recreationally for its significant mind-altering effects. PCP may cause hallucinations, distorted perceptions of sounds, and psychotic behavior. As a recreational drug, it is typically smoked, but may be taken by mouth, snorted, or injected. It may also be mixed with cannabis or tobacco. Adverse effects may include paranoia, addiction, and an increased risk of suicide, as well as seizures and coma in cases of overdose. Flashbacks may occur despite stopping usage. Chemically, PCP is a member of the arylcyclohexylamine class. PCP works primarily as an NMDA receptor antagonist. PCP is most commonly used in the US. While usage peaked in the US in the 1970s, between 2005 and 2011, an increase in visits to emergency departments as a result of the drug occurred. As of 2022, in the US, about 0.7% of 12th-grade students reported using PCP in the prior year, while 1.7% of people in the US over age 25 reported using it at some point in their lives.
== Adverse effects == Nutmeg intoxication is accompanied by unpleasant physical effects and feeling sick. Adverse effects of nutmeg have been reported to include malaise, nausea, vomiting, abdominal pain, dizziness, dry mouth, thirst, pupil constriction, skin flushing, reddening of the eyes, tachycardia, weak pulses, heart palpitations, hypotension, cold extremities, cyanosis, pallor, dyspnea, hypothermia, drowsiness, sedation, feeling heavy, lethargy, hyperactivity, agitation or restlessness, motor impairment, incoherent speech, loss of memory, stupor, delirium, insomnia, deep sleep, unconsciousness, and feelings and fears of impending death. After-effects are also said to be quite unpleasant and to include not feeling right, bone and muscle aches, eye soreness and aches, runny nose, tiredness, depression, and headaches. While some people may enjoy nutmeg intoxication, most find it to be a "rather grueling" experience, to be "too unpleasant to be addicting", and even to cause prolonged aversion to the spice.
Sources: en.wikipedia.org
=== Food analysis === The mouse bioassay developed for paralytic shellfish poisoning (PSP) can be used to monitor tetrodotoxin in pufferfish and is the current method of choice. An HPLC method with post-column reaction with alkali and fluorescence has been developed to determine tetrodotoxin and its associated toxins. The alkali degradation products can be confirmed as their trimethylsilyl derivatives by gas chromatography/mass spectrometry.
=== 16 August === At least 31 people were killed in RSF shelling on the Abu Shouk camp. The SAF destroyed 4,500 landmines, shells and other munitions recovered near Khartoum in a controlled detonation at the Wadi Seidna garrison as part of cleanup efforts. One person was killed in a grenade attack inside the main hospital of Zalingei.
A pathologists' assistant (PA or PathA) is a physician extender whose expertise lies in gross examination of surgical specimens as well as performing hospital, medicolegal, and forensic autopsies. Their education is analogous to physician assistants, consisting of a didactic and a clinical component and concluding in a master's degree. Certification of pathologists' assistants is through a board exam by the American Society for Clinical Pathology (ASCP). In the United States, the profession is represented by the American Association of Pathologists' Assistants (AAPA). Pathologists' Assistants in the United States are currently only required to be licensed in three states: Nevada, West Virginia, and New York. In most other states, the scope of PAs falls under CLIA high complexity testing which requires an associate degree.
Sources: en.wikipedia.org
Have a diagnosable opioid use disorder, according to the DSM-5, Be actively addicted to opioids at the time of intake, and Have been addicted to opioids for at least one year before beginning treatment. In addition to these federal criteria, each state may have its own criteria individuals must meet. The US GAO also cited the cost of treatment and lack of health insurance coverage for MAT as barriers for many addicted to opioids. While methadone treatments are covered by Medicaid for low-income individuals, the extent of coverage depends on which state they are in and if the state has opted into Medicaid expansion under the Affordable Care Act. Buprenorphine, on the other hand, is not covered by Medicaid or, often, even by private health insurers. Because buprenorphine must typically be paid for out-of-pocket, lower-income individuals are often priced out of the lower-risk MAT. In some areas this creates major disparities along racial lines with the higher-risk treatment utilized by lower-income individuals - disproportionately represented by people of color - and the lower-risk treatment only accessible to higher-income individuals - disproportionately represented by whites. Other individual-level barriers may include transportation, especially for those who live in rural areas. The nearest Opioid Treatment Program (OTP) could be up to an hour away, and when daily methadone doses are required for treatment, this may interfere with the success of the MAT or the client's compliance in the program.
=== MS fatigue === The mechanisms causing MS fatigue are not well understood. MS fatigue can be affected by body heat. Fatigability, defined as "decline in physical performance over time", correlates with perceived fatigue, but the limited correlation suggests they are distinct constructs and warrant independent assessment in clinical studies.
Isotopes are commonly used to determine the concentration of various elements or substances using the isotope dilution method, whereby known amounts of isotopically substituted compounds are mixed with the samples and the isotopic signatures of the resulting mixtures are determined with mass spectrometry.
Sources: en.wikipedia.org
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.
Creatine is converted to phosphocreatine in muscle, which helps regenerate adenosine triphosphate during brief, high-intensity activity. The body also obtains creatine from foods such as meat and fish.
The creatine molecule is the same whether from food or supplements, but the monohydrate form includes a water molecule in its crystal structure. Once dissolved, the monohydrate and food-derived creatine are chemically identical in the body.
Yes, especially when exposed to moisture or heat, where it converts to creatinine. In dry, sealed containers at room temperature, degradation is slow and the product may remain within specification for two to three years.