While creatine consumption has been greatly increasing among athletes and physical activity practitioners, the adverse effects of this supplement remain scientifically controversial, especially concerning renal function. The aim of this review is to describe the methodological limitations and gaps in the literature which contribute to the topic’s divergence. Case reports suggest that creatine is a nephrotoxic agent. On the other hand, despite having several limitations, longitudinal studies have indicated the opposite. Research with humans does not demonstrate any deleterious effects as a consequence of creatine supplementation; however, the absence of experimental control as well as their retrospective characteristics compromise the authors’ conclusion. Experimental studies with animal models though, use both gold standard for renal function and have satisfactory variable control. However, the results remain controversial. Future studies should investigate the effects of creatine supplementation in several kidneys diseases as well as in the elderly, type 2 diabetis and hypertensive individuals, whose tendency to renal dysfunction is well-described. There is not evidence that creatine supplementation causes renal deterioration in healthy subjects when it is ingested in the recommended dosage. Thus, we have some concerns about the sale prohibition of creatine supplementation in Brazil.
adverse effects; food supplements; creatinine; cystatin C; kidney
