What are side effects of creatine?

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.