What are side effects of creatine?

GI distress -- diarrhea, stomach upset, and bloating -- is the most common cited side effect of creatine. This may be related to large doses of creatine pulling excessive water into the intestines, leading to loose stools. Such GI distress is likely to hinder most athletic performances.

Although not a side effect, the increase in body mass caused by creatine may worsen performance in some sports, such as those that require considerable running.
Side effects of creatine -- a chemical made from amino acids and found in foods such as fish and meat -- range from relatively minor to quite serious. They're more likely to occur in people who take creatine supplements for six months or longer. Relatively minor side effects may include stomach pain, muscle strains and cramps, diarrhea and nausea. More serious side effects include weight gain, high blood pressure, liver dysfunction, kidney damage and possibly irregular heartbeats. Creatine can also interact with other supplements and with many prescription and nonprescription drugs, possibly increasing side effects from those medications. Talk to your doctor before taking creatine supplements.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.