Creatine monohydrate

Creatine is a naturally occurring nitrogen-containing organic compound that is present in every human cell, with the highest concentrations found in skeletal muscle, brain, heart, and other high-energy-demand tissues. The body synthesizes approximately half of its daily creatine requirement (about 1–2 grams per day) from the amino acids arginine, glycine, and methionine in the liver and kidneys; the remainder is obtained from dietary sources, primarily red meat and fish.¹² In muscle, creatine is stored predominantly as phosphocreatine, which serves as a rapid-mobilization energy reserve for regenerating adenosine triphosphate (ATP) during short, high-intensity efforts.²

Creatine monohydrate is the most extensively studied form of supplemental creatine and the form used in the majority of clinical research. The International Society of Sports Nutrition (ISSN) states that no other supplemental form has been shown to be superior to creatine monohydrate in terms of absorption, efficacy, or safety.²

Creatine monohydrate is among the most studied nutritional supplements. Per the 2017 ISSN position stand, creatine monohydrate is the most effective ergogenic nutritional supplement available for increasing high-intensity exercise capacity and lean body mass during training, and supplementation is safe and well-tolerated in healthy individuals at recommended doses.² The NIH Office of Dietary Supplements fact sheet on exercise and athletic performance similarly notes evidence supporting creatine's use for enhancing performance in repeated short bursts of high-intensity activity, including weight lifting and sprinting.¹

Beyond athletic performance, creatine has been investigated for a range of potential clinical applications including cognitive function, neurological conditions, muscular dystrophy, and recovery from injury.² The strength of evidence varies by application; performance and lean body mass effects in trained populations are the most robust findings.

Two commonly studied dosing approaches:²

• Loading phase plus maintenance: approximately 0.3 g/kg/day (often expressed as ~20 g/day divided into 4 doses of 5 g) for 5–7 days, followed by 3–5 g/day for maintenance.
• Continuous low-dose: 3–5 g/day from the outset, which achieves similar muscle saturation over approximately 3–4 weeks without the loading phase.

The ISSN reports that supplementation at up to 30 g/day for up to 5 years has been studied with no adverse effects in healthy individuals at recommended doses, and that long-term supplementation has not been shown to impair renal function in healthy adults with normal baseline kidney function.²

Oral. Typically mixed into water, juice, or a protein shake. Co-ingestion with carbohydrate or carbohydrate-plus-protein may modestly enhance muscle creatine uptake.²

Standard storage in a cool, dry place. Creatine monohydrate powder is generally stable; once dissolved in water, it should be consumed within a reasonable time period to minimize gradual conversion to creatinine (an inactive byproduct).

The most commonly reported side effect with creatine supplementation is short-term water retention, particularly during a loading phase, which typically presents as a small increase in body weight (1–2 kg or more) within the first week.² Gastrointestinal discomfort can occur with large single doses and is generally avoided by splitting the daily intake into multiple smaller doses with meals.²

Despite persistent public perception, the published clinical literature does not support claims that creatine monohydrate causes kidney damage or impaired renal function in healthy individuals with normal baseline kidney function.² Individuals with pre-existing kidney disease, or those taking medications affecting renal function, should consult their healthcare provider before supplementing.

Vegetarians and vegans, who consume little or no dietary creatine, may experience larger increases in muscle creatine concentrations with supplementation than omnivores.²