Creatine is an organic compound that plays a direct part in the energy system of the body’s cells, particularly in tissues that require rapid bursts of energy, such as skeletal muscle and the brain. It is stored primarily in muscle tissue in the form of phosphocreatine, which serves as a rapid reserve to regenerate adenosine triphosphate (ATP), the cell’s main energy currency, during high-intensity, short-duration activities. The body obtains this compound through three pathways: internal biological synthesis, consumption through food, and intake via manufactured supplements. Understanding these sources clarifies how the body maintains its creatine stores.
How the Body Creates Creatine
The human body naturally produces its own supply of creatine, a process known as endogenous synthesis. This internal production is a two-step process that primarily involves the kidneys and the liver. The daily turnover rate of creatine, which must be replaced by synthesis or diet, is approximately 2 grams in a typical adult male.
The synthesis begins in the kidneys, where the amino acids arginine and glycine are combined to form guanidinoacetate (GAA). This initial reaction is catalyzed by the enzyme L-arginine:glycine amidinotransferase (AGAT).
In the liver, the GAA molecule is converted into creatine through methylation. This step requires the amino acid methionine, which acts as a methyl donor. This synthesis pathway accounts for roughly half of the creatine needed by an omnivorous person.
Creatine in Food Sources
Creatine is also obtained exogenously through the consumption of animal products. Since creatine is stored in the muscle tissue of animals, the most concentrated dietary sources are meat and fish. These food sources contain creatine because the animal’s body utilized the compound for rapid muscle energy.
Red meat is a particularly rich source; beef contains an average of 4.5 grams of creatine per kilogram of raw meat (about 1 to 2 grams per pound). Pork is comparable, often containing around 5.0 grams of creatine per kilogram. Certain types of fish, such as herring, can contain up to 10 grams per kilogram.
Poultry, like chicken and turkey, also contains creatine but in lower amounts than red meat and many fish, with concentrations around 3.8 to 4.0 grams per kilogram. Achieving a supplemental dose of 5 grams of creatine requires consuming about one kilogram (2.2 pounds) of raw beef or pork, demonstrating the difficulty of relying solely on diet for high intake. Vegetarians and vegans typically have lower baseline creatine stores because plant-based foods contain only trace amounts of the compound.
Manufacturing of Supplemental Creatine
Commercial creatine monohydrate, the most widely used supplement form, is produced synthetically on an industrial scale through a controlled chemical process. It is not extracted from animal muscle tissue. This manufacturing method ensures high purity and allows for large-scale production independent of animal sourcing.
The synthesis process begins with two chemical raw materials: sarcosine and cyanamide. These compounds are combined in a reactor under controlled temperature and pressure to initiate a chemical reaction that forms creatine. The resulting raw creatine is then purified through multiple steps, including filtration and crystallization, to remove any unreacted starting materials or byproducts.
The final product is dried and milled into the fine powder familiar to consumers, often undergoing micronization to improve its solubility in liquids. This synthetic process allows manufacturers to produce creatine monohydrate with purity levels often exceeding 99.9%.