Anecdotal reports have suggested that creatine supplementation may promote dehydration, cramping, and musculoskeletal injury.4,20
Because many of these reports have emanated from certified athletic trainers and coaches, these conditions are commonly described as side effects from creatine supplementation.4,20
As a result, some certified athletic trainers and coaches have restricted the availability of creatine to their athletes (particularly during intense training periods performed in the heat), and some have warned against the use of creatine until more long-term data demonstrate its safety. In addition, some athletic organizations (eg, NCAA) have banned the practice of allowing teams to “provide” creatine to their athletes, citing safety and fairness issues, although athletes are still allowed to take creatine. We found that creatine use among Division IA football players training and competing in hot and humid environments did not significantly promote dehydration, cramping, or muscle injury in comparison with athletes who did not take creatine. Moreover, the athletes did not report a consistent pattern of “perceived” negative side effects as a result of the creatine-supplementation protocol. Within the scope of this study, these findings add to the growing body of evidence that creatine supplementation does not cause the anecdotally reported side effects and, to date, does not appear to cause health problems.6–9,14,15
Among the most commonly reported anecdotal side effects associated with creatine supplementation have been an increased incidence of dehydration or muscle cramping and decreased heat tolerance. In this regard, some have suggested that since creatine supplementation may increase work capacity, athletes who take creatine during training in hot and humid environments may experience a greater rate of dehydration, muscle cramping, or heat illness (or all 3).21
It also has been suggested that creatine ingestion promotes fluid retention, which may alter electrolyte status and promote muscle cramping by interfering with the muscle's contraction-relaxation mechanisms.4,21
Over the last few years, a number of researchers11,21
have examined the effects of creatine supplementation on hydration status, electrolyte levels, and dehydration during exercise performed in the heat and found that creatine does not promote dehydration, alter electrolyte levels, or increase thermal stress. In addition, there has been no evidence that creatine supplementation promotes muscle cramping among athletes.11,16,22
In fact, recent findings indicated that creatine supplementation may actually promote hydration,11,23
reduce thermal stress during exercise in the heat,11,22
and possibly reduce the incidence of injury.15,16,22
Our results suggest that the incidence of cramping and dehydration observed among creatine users was significantly lower than among nonusers.
Anecdotal reports have also suggested that creatine may promote a higher incidence of muscle injuries, such as muscle strains.4,17
Proponents of this theory postulated that because creatine supplementation may promote rapid increases in strength and body mass, the athlete may be more predisposed to additional stress placed on muscles, bones, joints, ligaments, and connective tissues. In our investigation, the incidence of muscle tightness, muscle strains, and total injuries was significantly lower among creatine users than among nonusers. There was also no evidence of a significant difference between creatine users and nonusers regarding the incidence of illness, missed practices, and players lost with a season-ending injury. If creatine supplementation increased the incidence of these problems, the incidence of injury among creatine users should have been markedly higher than among nonusers. However, the incidence of injury among athletes who took creatine during training was similar to or lower than that of athletes not taking creatine. It might be argued that creatine supplementation appeared to allow the athletes to tolerate training to a greater degree and, thereby, lessened the incidence of injury. These findings are similar to recent reports that creatine supplementation during training may lessen injury rates among athletes15,16,22
or hasten recovery after immobilization injury.24
Specifically, in a closely related study,22
investigators examined the effects of creatine supplementation on cramping and injury occurrence in 100 Division IA football players over a 3-year period. The incidence of cramping, dehydration, muscle tightness, muscle strains, noncontact injuries, and contact injuries among creatine users was similar to or lower than among nonusers. There was also no evidence of a greater proportion of individual injuries (eg, hamstring strains, groin strains, etc). Moreover, the incidences of illness, missed practices, and total injuries and the 1 player lost with a season-ending injury among the creatine users were similar to or lower than among the nonusers. The results of this 3-year investigation are closely related to the findings in our study.
In summary, our preliminary analysis suggests that collegiate football players who took creatine during training and competition did not experience a greater incidence of dehydration, cramping, or injury in comparison with collegiate football players not taking creatine. Although athletes who take creatine during intense training may experience some of these problems, the incidence of these problems was similar to or lower than among athletes not taking creatine in this study. Therefore, our findings may help to dispel anecdotal myths suggesting that creatine supplementation may increase the incidence of dehydration, cramping, or injury among athletes. In addition, we hope that these findings may help professionals involved in the training and medical supervision of athletes (ie, athletic coaches, certified athletic trainers, researchers, certified strength and conditioning coaches, nutritional consultants, administrators, athletic governing bodies) to better examine the methods employed to train and manage athletes (ie, 3-a-day training in extreme climates, exhaustive conditioning drills, hydration practices, etc). In this regard, it appears that the type of activities and conditions in which athletes are asked to train and compete may place them at a greater risk of dehydration, cramping, or injury than creatine supplementation.