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
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
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.
1. Greenhaff PL, Bodin K, Soderlund K, et al. Effect of oral creatine
supplementation on skeletal muscle phosphocreatine resynthesis. Am J Physiol
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
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
6. Becque MD, Lochmann JD, Melrose DR. Effects of oral creatine
supplementation on muscular strength and body composition. Med Sci Sports Exerc
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
10. Vandenberghe K, Gills N, Van Leemputte M, et al. Caffeine counteracts
the ergogenic action of muscle creatine loading. J Appl Physiol
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
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
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
16. Poortmans JR, Francaux M. Long-term oral creatine supplementation
does not impair renal function in healthy athletes. Med Sci Sports Exerc
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
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].