Creatine
... Symptoms of a creatine overdose are not known. It is cautioned that long-term use of creatine may cause kidney damage. What should I avoid while taking creatine? What are the possible side effects of creatine? Although uncommon, serious side effects have been reported with the use of creatine. Stop taking creatine and seek emergency medical attention or notify your doctor immediately if you experience: • an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives); or • symptoms of kidney problems such as decreased or little urine.