creatinine 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.
Updated 2025-04-28. Numbers and descriptions here follow the published literature rather than marketing material.
Identity and purity are commonly assessed by high-performance liquid chromatography, often with ultraviolet detection, and by spectroscopic techniques such as infrared or nuclear magnetic resonance. These methods can distinguish creatine from creatinine and detect related impurities. Moisture content may be measured by Karl Fischer titration or loss on drying. Particle size, bulk density, and heavy metal limits are additional quality parameters. Not every product is tested by every method, so specifications depend on the intended use and regulatory framework.
Solid creatine monohydrate is generally stable when kept dry and protected from extremes of heat and humidity. In the presence of moisture, it can gradually convert to creatinine, a cyclic dehydration product that has little value for phosphocreatine synthesis. Elevated temperatures and acidic conditions accelerate this conversion in solution. Because the reaction is slow in cool, dry storage, typical shelf lives are measured in years rather than weeks. Packaging that limits moisture and oxygen exposure helps maintain purity.
Commercial creatine monohydrate is typically a white to off-white powder with low odor. It is commonly sold as a fine powder, micronized powder, or larger crystals, but these are physical forms of the same chemical. Purity grades vary, and products may contain small amounts of related substances such as creatinine, dicyandiamide, or moisture. The monohydrate is often selected for supplements and research because its production is well established and its behavior in water is predictable. Analytical certificates usually report assay, loss on drying, and heavy metals.
Creatine monohydrate is a crystalline compound formed from creatine and one water molecule in its solid lattice. Creatine itself is a nitrogen-containing organic acid involved in energy transfer in muscle and other tissues. The monohydrate form is the most common solid form used in research and commercial products because it is stable and easy to handle. The term "monohydrate" refers to the fixed one-to-one ratio of water to creatine in the crystal, not to moisture content. This distinction matters when comparing labels or calculating creatine content.
In chemical terms, creatine monohydrate is often described as N-(aminoiminomethyl)-N-methylglycine monohydrate, though nomenclature varies. Its solid state consists of zwitterionic creatine molecules linked with water through hydrogen bonding. The compound dissolves in water, but dissolution rate depends on particle size, temperature, and agitation. Once dissolved, the hydrate water becomes part of the solvent, leaving free creatine in solution. The monohydrate is not the same as creatine anhydrous, which lacks the water of crystallization and has a higher creatine fraction by mass.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | 15–25 °C | Cool, dry, sealed conditions slow conversion to creatinine. |
| Moisture sensitivity | Moderate | Absorbs water from humid air, which can cause caking. |
| Primary purity method | HPLC-UV | Separates creatine from creatinine and related impurities. |
| Moisture method | Karl Fischer titration | Measures water content; loss on drying is an alternative. |
| Degradation product | Creatinine | Forms by dehydration, especially in solution or humid heat. |
Creatine monohydrate is sold as a dietary ingredient in some countries and as a food supplement in others. Regulatory frameworks vary, so purity limits, labeling rules, and permitted claims are not globally uniform. In the United States, it falls under dietary supplement rules, whereas the European Union treats it as a food supplement ingredient. Pharmacopeial monographs, where they exist, can provide public quality standards, but not every product is required to meet them. Questions about long-term effects and patterns of use remain areas of active study rather than settled regulatory findings.
Solid creatine monohydrate is generally stable when kept cool and dry, but it can hydrolyze to creatinine over time. Moisture, heat, and acidic conditions accelerate this conversion, which reduces assay values and changes the material's properties. Creatinine is a cyclic dehydration product that is also a normal human metabolite, so its presence in a sample is not necessarily a health concern by itself. In quality testing, creatinine is monitored as a marker of degradation and purity.
Identity and purity are assessed with several complementary methods. High-performance liquid chromatography can separate creatine from creatinine and related impurities, often with ultraviolet detection. Nuclear magnetic resonance and infrared spectroscopy provide structural confirmation, while Karl Fischer titration measures water content. Elemental analysis and mass spectrometry may be used for additional confirmation, especially in research or forensic settings. No single method captures every quality attribute, so laboratories typically combine results and compare them against a specification.
When the apical bud is removed, the lowered IAA concentration allows the lateral buds to grow and produce new shoots, which compete to become the lead growth. Pruning techniques such as coppicing and pollarding make use of this natural response to curtail direct plant growth and produce a desired shape, size, and/or productivity level for the plant. The principle of apical dominance is manipulated for espalier creation, hedge building, or artistic sculptures called topiary. If the SAM is removed, it stimulates growth in the lateral direction. By careful pruning, it is possible to create remarkable designs or patterns. Some fruit trees have strong apical dominance, and young trees can become "leggy", with poor side limb development. Apical dominance can be reduced in this case, or in cases where limbs are broken off by accident, by cutting off the auxin flow above side buds that one wishes to stimulate. This is often done by orchardists for young trees. Occasionally, strong apical dominance is advantageous, as in the "Ballerina" apple trees. These trees are intended to be grown in small gardens, and their strong apical dominance combined with a dwarfing rootstock gives a compact narrow tree with very short fruiting side branches.
A number of AlphaFold clones have also been published, mostly with permissive license terms. Clones for AlphaFold3 include ByteDance's Protenix (Apache 2.0 License), AlQuraishi Laboratory's OpenFold-3 (MIT license), and Boltz-1/2 (MIT license). There are also clones for older versions, though they became less relevant with the open-source release of AlphaFold 1 and 2 source codes. Still relevant are models, both open- and closed-source, that include modifications to the AlphaFold architecture. For AlphaFold 2, a notable example is ESMFold from Meta, which replaces the multiple sequence alignment with the latent space of a protein language model. Open-source tools that complement AlphaFold have also been made. One well-cited example is ColabFold, which uses MMseqs2 instead of HHblits to speed up the sequence search, allowing the AlphaFold pipelines to run quickly on Google Colab.
(CH3)2CO → CH3 + CH3CO The latter process is relevant to the atmospheric chemistry of acetone. Acetone can then be metabolized either by CYP2E1 via methylglyoxal to D-lactate and pyruvate, and ultimately glucose/energy, or by a different pathway via propylene glycol to pyruvate, lactate, acetate (usable for energy) and propionaldehyde. About a third of the world's acetone is used as a solvent, and a quarter is consumed as acetone cyanohydrin, a precursor to methyl methacrylate. Acetone is used to synthesize methyl methacrylate. It begins with the initial conversion of acetone to acetone cyanohydrin via reaction with hydrogen cyanide (HCN): (CH3)2CO + HCN → (CH3)2C(OH)CN In a subsequent step, the nitrile is hydrolyzed to the unsaturated amide, which is esterified: (CH3)2C(OH)CN + CH3OH → CH2C(CH3)CO2CH3 + NH3 The third major use of acetone (about 20%) is synthesizing bisphenol A. Bisphenol A is a component of many polymers such as polycarbonates, polyurethanes, and epoxy resins. The synthesis involves the condensation of acetone with phenol:
Most commonly 2,5-diketopiperazines are generated by cyclisation of dipeptides. In addition to the many methods of peptide synthesis, the Ugi reaction can be applied. Dipeptides with an ester terminus spontaneously cyclize often. Racemization can be problematic. The Ugi reaction using an isonitrile, amino acid, aldehyde and amine, can produce a dipeptide in equally high yield and optical purity, to that formed by standard peptide couplings. Commonly, an isonitrile is chosen to give a labile terminal amide to enable cyclization. For example, the direct 2,5-DKP ring formation via such an activated leaving group using the stable, easily accessible and versatile convertible isonitrile 1-isocyano-2-(2,2-dimethoxyethyl)-benzene 4 gave a one-pot synthesis of N-substituted 2,5-diketopiperazine's 7.
BOP (benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate) is a reagent commonly used for the synthesis of amides from carboxylic acids and amines in peptide synthesis. It can be prepared from 1-hydroxybenzotriazole and a chlorophosphonium reagent under basic conditions. This reagent has advantages in peptide synthesis since it avoids side reactions like the dehydration of asparagine or glutamine residues. BOP has used for the synthesis of esters from the carboxylic acids and alcohols. BOP has also been used in the reduction of carboxylic acids to primary alcohols with sodium borohydride (NaBH4). Its use raises safety concerns since the carcinogenic compound HMPA is produced as a stoichiometric by-product. PyBOP, a related phosphonium reagent for amide bond formation PyAOP, a related phosphonium reagent for amide bond formation
Sources: en.wikipedia.org
Nycomed, a Swiss drug company which manufactures Actovegin, claims it can be used for circulation and nutrition disturbances, skin grafting, burns, and wound-healing impairment. Actovegin has also been used as a performance enhancer. It has been investigated for use in treatment of polyneuropathy in diabetes, and for stroke. One study found that when tissues suffer from hypoxia caused circulation abnormalities, Actovegin helps capillaries improve circulation by enhancing the neogenic mechanism in blood vessels. Anaphylactic shock has been observed in at least one patient treated with actovegin. There are reports suggesting that Actovegin have ergogenic ability, however one small trial found no apparent benefit from short-term use. Two studies certified Actovegin to have an anti-inflammatory effect. One of the two studies certified Actovegin to reduce Progressive muscular atrophy-induced inflammation in human cells. Another study certified Actovegin to have a positive impact on the growth of muscle cells.
One mechanism through which BDNF appears to maintain elevated levels of neuronal excitation is through preventing GABAergic signaling activities. While glutamate is the brain's major excitatory neurotransmitter and phosphorylation normally activates receptors, GABA is the brain's primary inhibitory neurotransmitter and phosphorylation of GABAA receptors tend to reduce their activity. Blockading BDNF signaling with a tyrosine kinase inhibitor or a PKC inhibitor in wild type mice produced significant reductions in spontaneous action potential frequencies that were mediated by an increase in the amplitude of GABAergic inhibitory postsynaptic currents (IPSC). Similar effects could be obtained in BDNF knockout mice, but these effects were reversed by local application of BDNF. This suggests BDNF increases excitatory synaptic signaling partly through the post-synaptic suppression of GABAergic signaling by activating PKC through its association with TrkB. Once activated, PKC can reduce the amplitude of IPSCs through to GABAA receptor phosphorylation and inhibition. In support of this putative mechanism, activation of PKCε leads to phosphorylation of N-ethylmaleimide-sensitive factor (NSF) at serine 460 and threonine 461, increasing its ATPase activity which downregulates GABAA receptor surface expression and subsequently attenuates inhibitory currents.
Initial letters are used where there is no ambiguity: C cysteine, H histidine, I isoleucine, M methionine, S serine, V valine. No other amino acids in this set begin with each of those letters. Where arbitrary assignment is needed, the structurally simpler amino acids are given precedence: A alanine, G glycine, L leucine, P proline, T threonine. For example, alanine is simpler than arginine or asparagine, the other amino acids starting with "a". F PHenylalanine and R aRginine are assigned by being phonetically suggestive, W tryptophan is assigned based on the double ring being visually suggestive to the bulky letter W, K lysine and Y tyrosine are assigned as alphabetically nearest to their initials L and T (note that U was avoided for its similarity with V, while X was reserved for undetermined or atypical amino acids); for tyrosine the mnemonic tYrosine was also proposed, D aspartate was assigned arbitrarily, with the proposed mnemonic asparDic acid; E glutamate was assigned in alphabetical sequence being larger by merely one methylene –CH2– group, N asparagine was assigned arbitrarily, with the proposed mnemonic asparagiNe; Q glutamine was assigned in alphabetical sequence of those still available (note again that O was avoided due to similarity with D), with the proposed mnemonic Qlutamine.
Membrane blebbing: The cell membrane shows irregular buds known as blebs. Initially these are smaller surface blebs. Later these can grow into larger so-called dynamic membrane blebs. An important regulator of apoptotic cell membrane blebbing is ROCK1 (rho associated coiled-coil-containing protein kinase 1). Formation of membrane protrusions: Some cell types, under specific conditions, may develop different types of long, thin extensions of the cell membrane called membrane protrusions. Three types have been described: microtubule spikes, apoptopodia (feet of death), and beaded apoptopodia (the latter having a beads-on-a-string appearance). Pannexin 1 is an important component of membrane channels involved in the formation of apoptopodia and beaded apoptopodia. Fragmentation: The cell breaks apart into multiple vesicles called apoptotic bodies, which undergo phagocytosis. The plasma membrane protrusions may help bring apoptotic bodies closer to phagocytes.
Isoforms I, III, and VIII are also stimulated by Ca2+/calmodulin. Isoforms V and VI are inhibited by Ca2+ in a calmodulin-independent manner. Isoforms II, IV and IX are stimulated by alpha subunit of the G protein. Isoforms I, V and VI are most clearly inhibited by Gi, while other isoforms show less dual regulation by the inhibitory G protein. Soluble AC (sAC) is not a transmembrane form and is not regulated by G proteins or forskolin, instead acts as a bicarbonate/pH sensor. It is anchored at various locations within the cell and, with phosphodiesterases, forms local cAMP signalling domains. In neurons, calcium-sensitive adenylyl cyclases are located next to calcium ion channels for faster reaction to Ca2+ influx; they are suspected of playing an important role in learning processes. This is supported by the fact that adenylyl cyclases are coincidence detectors, meaning that they are activated only by several different signals occurring together. In peripheral cells and tissues adenylyl cyclases appear to form molecular complexes with specific receptors and other signaling proteins in an isoform-specific manner.
Sources: en.wikipedia.org
The Bergmann degradation is intended for and has been used as a method for peptide sequencing. It was also proposed for use in cleaving the 3,4-bond of the penicillin nucleus. The compound 2,2-dimethyl-6-phthalimido-3-penamyl isocyanate was arrived at through various means, including the Curtius rearrangement, and it was envisioned that it could undergo the Bergmann degradation to form the desired aldehyde as well as the urea by-product. Though the Bergmann degradation was indeed possible, it was discovered that simple dilute acid hydrolysis would suffice in forming the desired product.
Alkaline lysis is often an initial step in molecular biology experiments, allowing specific DNA molecules to be extracted and purified so that it can subsequently be used in downstream applications. When performed properly, alkaline lysis yields pure DNA exclusively from bacterial plasmids. A plasmid is a small circular DNA molecule that is found naturally in certain cell types, most commonly bacterial cells, and replicates independently of the cell's chromosomal or genomic DNA. Plasmids can also be found less commonly in archaeal and eukaryotic cells. They often contain genetic information useful to the host cell, such as genes that confer antibiotic resistance or virulence factors. Plasmids are readily uptaken by bacterial cells from the environment and can be passed between cells by various forms of horizontal transmission such as transduction, transformation, and conjugation, as well as by vertical transmission from parent to offspring. Because of their versatility and relatively simple manipulation, plasmids are of interest to scientists and have become a standardized laboratory tool by which recombinant DNA is artificially introduced into cells and genomes. The basic process of alkaline lysis involves a series of steps which can be performed in the laboratory:
Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins are commonly found in blood plasma and differ from other blood proteins in that they are not glycosylated. Substances containing albumins are called albuminoids. A number of blood transport proteins are evolutionarily related in the albumin family, including serum albumin, alpha-fetoprotein, vitamin D-binding protein and afamin. This family is only found in vertebrates. Albumins in a less strict sense can mean other proteins that coagulate under certain conditions. See Other albumin types for lactalbumin, ovalbumin and plant "2S albumin". Albumins in general are transport proteins that bind to various ligands and carry them around. Human types include:
Before amylin deposition was associated with diabetes, already in 1901, scientists described the phenomenon of "islet hyalinization", which could be found in some cases of diabetes. A thorough study of this phenomenon was possible much later. In 1986, the isolation of an aggregate from an insulin-producing tumor was successful, a protein called IAP (Insulinoma Amyloid Peptide) was characterized, and amyloids were isolated from the pancreas of a diabetic patient, but the isolated material was not sufficient for full characterization. This was achieved only a year later by two research teams whose research was a continuation of the work from 1986.
Sources: en.wikipedia.org
Solid product can remain within specification for years when stored dry and sealed, but expiration dates reflect manufacturer testing and regulatory conventions. Moisture and heat increase conversion to creatinine, so storage conditions matter more than the printed date alone. Degradation is gradual and can be monitored by purity testing.
Purity is typically evaluated by chromatographic separation with ultraviolet detection, sometimes supported by spectroscopic identity tests. Moisture and creatinine content are common quality parameters. Results depend on the analytical method, sample preparation, and specification limits.
Clumping occurs when powder absorbs moisture, causing particles to stick together. Humidity, temperature changes, and repeated container opening promote this effect. Clumps do not necessarily indicate chemical degradation, but they can affect weighing and mixing.
It is a solid form of creatine that contains one water molecule per creatine molecule in the crystal lattice. The hydrate water is part of the crystal structure rather than loose moisture. The term is often used for the common crystalline powder grade.