Long-Term Creatine Use Shows No Adverse Events; Ineffective In Short-Term Use
BOONE, N.C.--In the February issue of Medicine and Science in Sports and Exercise (33, 2: 183-8, 2001), a retrospective study looked at creatine's relationship with a person's health, and reported adverse events and perceived training benefits. Researchers divided 26 subjects (18 men, eight women) into nonusers (the control group), short-term users (0.8 to 1.0 years) and long-term users (over one year), noting each group's blood concentrations of testosterone, cortisol and growth hormone levels after a 12-hour fast; subjects also filled out a questionnaire on creatine usage. Participants had a mean loading dose of 13.7 g/d and the maintenance dose of 9.7 g/d. There was no difference between the groups with regard to muscle injury, cramps or other side effects. Overall, researchers concluded that this data shows that long-term creatine supplementation does not lead to adverse events.
While long-term creatine use may not cause adverse events, short-term use may not prove effective in enhancing performance for irregular bouts of heavy resistance training. In the March edition of the same journal (33(3): 449-53, 2001), researchers from the Katholieke Universiteit Leuven in Belgium found that creatine supplementation did not alter the hormonal response to resistance training. In a double-blind, crossover study, 11 healthy male volunteers did one hour of heavy resistance training (three reps of 10 for 12 different exercises) both before and after five days of taking either a placebo or creatine (20 g/d). The scientists noted that exercise-induced levels of serum growth hormone and testosterone were not affected by acute creatine intake, and it did not significantly increase cortisol levels. The study's authors concluded that short-term creatine supplementation does not alter hormonal response during a single bout of heavy resistance training. For more on these studies, visit www.ncbi.nlm.nih.gov and conduct a key word search using PubMed.