Is Creatine a Performance Enhancing Drug? Should its Use be Banned in Collegiate Sports?

The enzyme creatine kinase (CK) is crucial for energy homeostasis during periods of high, fluctuating energy requirements. This enzyme catalyzes the reversible transfer of the N-phosphoryl group from phosphocreatine (PCr) to ADP which regenerates ATP and creatine (Cr) (Wallimann, et al., 1998). As such, CK is predominately active in skeletal and cardiac muscles. Furthermore, creatine kinase is essential for fast muscle contraction under anaerobic conditions. Since ATP concentration decreases within 30 seconds of initial muscle activity and aerobic metabolism does not peak until an hour of muscle contractions, CK is necessary to supply ATP to active muscles within this time frame (Wallimann, et al., 1998). Therefore, creatine phosphate is a reservoir of high-potential phosphoryl groups that can be transferred to ADP during anaerobic conditions. As such, supplementation of creatine could enhance these effects.

The National Institutes of Health (NIH) reports that Americans use 8.8 million pounds of creatine annually (Kreider, et al., 2017). Recent surveys also indicate that up to 41% of NCAA athletes from 17 different sports use creatine supplements (Rawson & Volek, 2003). As such, creatine supplementation is widely used among the general population and athletes. However, does the supplement provide any noticeable effects and advantage to the user?

Based upon athlete surveys, creatine supplementation does provide a wide range of discernable effects: 92% of athletes reported increased muscle strength; 85% reported increased muscle size; 47% reported substantial weight gain; and 81% reported shorter recovery periods (Greenwood, et al., 2000). Furthermore, data from group studies support the claims presented within these surveys. From the 22 studies reviewed within the 2003 article by Rawson et al., 16 of the studies reported significant improvement in muscle strength and weightlifting performance within subjects who used creatine supplements. The average increase in muscle strength and weightlifting performance was 8-14% greater in the groups using creatine than the placebo groups (Rawson & Volek, 2003). In addition, effects of supplementation were similar between men and women which indicates that everyone can benefit from creatine usage.

As such, there is both quantitative and qualitative evidence that indicates the advantages of creatine supplementation. Therefore, should creatine be considered a performance enhancing drug (PED) in the same fashion of steroids? If this is the case, then what should be the ethics of creatine supplementation (i.e. who should be able to use it and when is it appropriate)? If it is not the case, then what is the performance threshold (i.e. the performance boost of a supplement) that renders a substance to be a PED?

References

Greenwood, M., Farris, J., Kreider, R., Greenwood, L., & Byars, A. (2000). Creatine Supplementation Patterns and Perceived Effects in Select Division I Collegiate Athletes. Clinical Journal of Sport Medicine, 10(3), 191–194.

Kreider, R. B., Kalman, D. S., Antonio, J., Ziegenfuss, T. N., Wildman, R., Collins, R., … Lopez, H. L. (2017). International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition, 14(1).

Rawson, E. S., & Volek, J. S. (2003). Effects of Creatine Supplementation and Resistance Training on Muscle Strength and Weightlifting Performance. The Journal of Strength and Conditioning Research, 17(4), 822.

Wallimann, T., Dolder, M., Schlattner, U., Eder, M., Hornemann, T., Ogorman, E., … Brdiczka, D. (1998). Some new aspects of creatine kinase (CK): compartmentation, structure, function and regulation for cellular and mitochondrial bioenergetics and physiology. BioFactors, 8(3-4), 229–234.