University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• What advice can I give to my adolescent patients concerning the safety and effectiveness of creatine supplementation for the enhancement of sports performance?

Clinical Bottom Lines

1. Creatine Monohydrate may be effective in enhancing physical performance of high intensity, short term (<30 seconds) tasks.
2. Creatine Monohydrate is not effective in enhancing physical performance in longer term tasks both in the laboratory and on the playing field.
3. Although no serious adverse effects have been reported in healthy people with short term supplementation, there have been no long term studies performed.
4. I would not recommend the use of Creatine Monohydrate for adolescent athletes as it has no proven beneficial effects on performance of typical high school sports activities and may have long term adverse health consequences.

Summary of Key Evidence

1. Creatine supplementation does increase both total and phosphocreatine levels in skeletal muscle.
2. Most but not all studies of short term high intensity tasks show a benefit to supplementation.
3. Both laboratory and field studies of longer term tasks (>30 seconds) at high intensity and also prolonged sub-maximal exercise show no beneficial effect.
4. Studies suggest that Caffeine supplementation negates all of the short term benefits.
5. Short term supplementation increases body mass through increased body water and this has been shown to have an adverse effect on performance in sports such as swimming and long distance running.
6. Although there have been no reported or measured adverse effects of short term supplementation, no long term studies have been performed.

Additional Comments

• To the authors' credit, they included all relevant trials, included individual study methodologies, discussed study validity, and attempted to explain inconsistencies in the study results.  However, not all included studies are randomized studies and there is no methods section for their own analysis.

• Most studies show an increase in both total and phosphorylated creatine (PCR) in muscle biopsies.  PCR serves as a donor of phosphate to recycle ATP from ADP.  Of note, individuals who had the highest increase of PCR had sub-normal baseline levels and those who had normal baseline levels had almost no benefit as measured by muscle biopsy.

• The use of creatine may be considered unethical as it is a type of blood doping.  Unfortunately, its use is undetectable with current drug testing.

Citation

1. Williams M, Branch J. Creatine supplementation and exercise performance: an update. J Am College of Nutrition. 17(3):216-34, 1998.
2. Clark JF.  Creatine: a review of its nutritional applications in sports. Nutrition.  14(3):322-4, 1998.
3. Mujika I, Padilla S. Creatine supplementation as an ergogenic aid for sports performance in highly trained athletes: a critical review.  International Journal of Sports Medicine. 18(7):491-6, 1997.

CAT Author: Joshua Plavin, MD

CAT Appraisers: John Frohna, MD

Date appraised: November 2, 1998