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
- Williams M, Branch J. Creatine supplementation and exercise performance:
an update. J Am College of Nutrition. 17(3):216-34, 1998.
- Clark JF. Creatine: a review of its nutritional applications
in sports. Nutrition. 14(3):322-4, 1998.
- 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.