What are the side effects of using creatine?

Creatine: Drink plenty of fluid while taking creatine. Although it has not been proven, dehydration, heat-related illnesses, muscle cramps, reduced blood volume, and electrolyte imbalances are expected to be more likely to occur while taking creatine. Creatine has not been evaluated by the FDA for safety, effectiveness, or purity. All potential risks and/or advantages of creatine may not be known. Additionally, there are no regulated manufacturing standards in place for these compounds. There have been instances where herbal/health supplements have been sold which were contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.