The main side effects reported by people taking creatine supplements are dehydration, stomach upset, and diarrhea. In rare cases, people have experienced kidney damage, liver damage, and blood clots.
Creatine can also cause weight gain and swelling related to extra water being stored in the body. Some people have reported an inability to tolerate heat after starting creatine supplements. Muscle cramping can also occur.
Allergic reactions can occur. If you experience symptoms such as itching, hives, swelling of face or tongue, chest tightness, or difficulty breathing, seek immediate medical attention. If you have had an allergic reaction to creatine, do not take this supplement.
If you have kidney or liver problems, avoid creatine.
Creatine should not be taken by children, or by people who are pregnant or breast-feeding. Additionally, people who have bipolar disorder should not take creatine.
Creatine may interact with caffeine and increase your risk of developing serious side effects such as strokes.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.