Creatine Monohydrate
Creatine (creatine monohydrate) is a colorless, crystalline substance used in muscle tissue for the production of phosphocreatine, an important factor in the formation of adenosine triphosphate (ATP), the source of energy for muscle contraction and many other functions in the body.1 2
Where is it found?
Creatine is produced naturally in the human liver, pancreas, and kidneys. It is concentrated primarily in muscle tissues, including the heart. Animal proteins, including fish, are the main source of the 1–2 grams per day of dietary creatine most people consume. Supplements in the form of creatine monohydrate are well absorbed and tolerated by the stomach.
Creatine monohydrate has been used in connection with the following conditions (refer to the individual health concern for complete information):
Who is likely to be deficient?
People involved in intense physical activity, especially those limiting their intake of red meat, may have low muscle stores of creatine. Several muscle diseases, as well as rheumatoid arthritis, and chronic circulatory and respiratory diseases, are associated with lowered creatine levels.3
How much is usually taken?
Two methods are used for supplementing with creatine. In the loading method, 20 grams of creatine per day (in four divided amounts mixed well in warm liquid) are taken for five to six days.4 Muscle creatine levels increase rapidly, which is beneficial if a short-term rise in force is needed, such as during a weight-lifting competition, football game, or sprinting. To maintain muscle creatine levels after this loading period, 2–10 grams per day may be effective.5 6
In another method, 3 grams of creatine monohydrate per day are taken over an extended training period of at least four weeks, during which muscle creatine levels rise more slowly, eventually reaching levels similar to those achieved with the loading method.7 However, no trials testing exercise performance changes have been done using this method. Taking creatine with sugar appears to maximize muscle uptake.8 9
Caffeine intake should not be excessive, as large amounts may counteract the benefits of creatine supplementation.10
Are there any side effects or interactions?
Little is known about long-term side effects of creatine, but no consistent toxicity has been reported in studies of creatine supplementation. In a study of side effects of creatine, diarrhea was the most commonly reported adverse effect of creatine supplementation, followed by muscle cramping.11 Some reports showed that kidney, liver, and blood functions were not affected by short-term higher amounts12 13 or long-term lower amounts 14 15 of creatine supplementation in healthy young adults. In a small study of people taking 5–30 grams per day, no change in kidney function appeared after up to five years of supplementation.16 However, interstitial nephritis, a serious kidney condition, developed in an otherwise healthy young man, supplementing with 20 grams of creatine per day.17 Improvement in kidney function followed avoidance of creatine. Details of this case strongly suggest that creatine supplementation triggered this case of kidney disease. Creatine supplementation may also be dangerous for people with existing kidney disease. In one report, a patient with nephrotic syndrome (a kidney disorder) developed glomerulosclerosis (another serious kidney condition) while taking creatine. when the creatine was discontinued, the glomerulosclerosis resolved.18
Muscle cramping after creatine supplementation has been anecdotally reported in three studies.19 20 21
At the time of writing, there were no well-known drug interactions with creatine monohydrate.
References (To view, roll mouse over the "References" heading; to hide, click on the heading)
1. Greenhaff PL, Bodin K, Soderlund K, et al. Effect of oral creatine supplementation on skeletal muscle phosphocreatine resynthesis. Am J Physiol 1994;266:E725-30.
2. Greenhaff PL. Creatine and its application as an ergogenic aid. Int J Sport Nutr 1995;5:94-101.
3. Silber ML. Scientific facts behind creatine monohydrate as a sports nutrition supplement. J Sports Med Phys Fitness 1999;39:179–88 [review].
4. Greenhaff PL. The nutritional biochemistry of creatine. J Nutr Biochem 1997;8:610–8.
5. Vandenberghe K, Goris M, Van Hecke P, et al. Long-term creatine intake is beneficial to muscle performance during resistance training. J Appl Physiol 1997;83:2055–63.
6. Becque MD, Lochmann JD, Melrose DR. Effects of oral creatine supplementation on muscular strength and body composition. Med Sci Sports Exerc 2000;32:654–8.
7. Hultman E, Soderlund K, Timmons J, et al. Muscle creatine loading in man. J Appl Physiol 1996;81:232–7.
8. Green AL, Hultman E, Macdonald IA, et al. Carbohydrate ingestion augments skeletal muscle creatine accumulation during creatine supplementation in man. Am J Physiol 1996;271:E821–6.
9. Feldman EB. Creatine: a dietary supplement and ergogenic aid. Nutr Rev 1999;57:45–50.
10. Vandenberghe K, Gills N, Van Leemputte M, et al. Caffeine counteracts the ergogenic action of muscle creatine loading. J Appl Physiol 1996;80:452–7.
11. Juhn MS, O’Kane JW, Vinci DM. Oral creatine supplementation in male collegiate athletes: a survey of dosing habits and side effects. J Am Diet Assoc 1999;99:593–5.
12. Sewell DA, Robinson TM, Casey A, et al. The effect of acute dietary creatine supplementation upon indices of renal, hepatic and haematological function in human subjects. Proc Nutr Soc 1998;57:17A.
13. Poortmans JR, Auquier H. Renaut V, et al. Effect of short-term creatine supplementation on renal responses in men. Eur J Appl Physiol Occup Physiol 1997;76:566–7.
14. Earnest C, Almada A, Mitchell T. Influence of chronic creatine supplementation on hepatorenal function. FASEB J 1996;10:4588.
15. Almada A, Mitchell T, Earnest C. Impact of chronic creatine supplementation on serum enzyme concentrations. FASEB J 1996;10:4567.
16. Poortmans JR, Francaux M. Long-term oral creatine supplementation does not impair renal function in healthy athletes. Med Sci Sports Exerc 1999;31:1108–10.
17. Koshy KM, Griswold E, Schneeberger EE. Interstitial nephritis in a patient taking creatine. N Engl J Med 1999;340:814–5 [letter].
18. Pritchard NR, Kaira PA. Renal dysfunction accompanying oral creatine supplements. Lancet 1998;351:1252–3 [letter].
19. Hultman E, Soderlund K, Timmons J, et al. Muscle creatine loading in man. J Appl Physiol 1996;81:232–7.
20. Vandenberghe K, Goris M, Van Hecke P, et al. Long-term creatine intake is beneficial to muscle performance during resistance training. J Appl Physiol 1997;83:2055–63.
21. Juhn MS, Tarnopolsky M. Potential side effects of oral creatine supplementation: a critical review. Clin J Sport Med 1998;8:298–304 [published erratum appears in Clin J Sport Med 1999;9:62].
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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2009.