well, I don't think there is good long term data on creatine. But so far, saying it is dangerous is wrong. It's more likely that, like most things, taking it in reasonable doses is ok, more than that, who knows. Heck, I don't really think much bad has been proven about anabolic steroids once you are past adolescence and development. I always love it when the idiot media will start talking about steroids causing the death of Lyle Alzado when there is absolutely NO relationship between steroids and the development of brain tumors. but, hey, doctorb Alzado says they caused it, so it must be true.
Here is an abstract from a review article written in the Journal of Sports Medicine and Physical Fitness:
J Sports Med Phys Fitness. 2004 Dec;44(4):411-6. Related Articles, Links
Is the use of oral creatine supplementation safe?
Bizzarini E, De Angelis L.
School of Sports Medicine, University of Trieste, Trieste, Italy.
This review focuses on the potential side effects caused by oral creatine supplementation on gastrointestinal, cardiovascular, musculoskeletal, renal and liver functions. No strong evidence linking creatine supplementation to deterioration of these functions has been found. In fact, most reports on side effects, such as muscle cramping, gastrointestinal symptoms, changes in renal and hepatic laboratory values, remain anecdotal because the case studies do not represent well-controlled trials, so no causal relationship between creatine supplementation and these side-effects has yet been established. The only documented side effect is an increase in body mass. Furthermore, a possibly unexpected outcome related to creatine monohydrate ingestion is the amount of contaminants present that may be generated during the industrial production. Recently, controlled studies made to integrate the existing knowledge based on anecdotal reports on the side effects of creatine have indicated that, in healthy subjects, oral supplementation with creatine, even with long-term dosage, may be considered an effective and safe ergogenic aid. However, athletes should be educated as to proper dosing or to take creatine under medical supervision.
From another review article from U of Oklahoma:
There appears to be no strong scientific evidence to support any adverse effects but it should be noted that there have been no studies to date that address the issue of long-term Cr usage.