The main side effects reported by people taking creatine supplements are stomach upset, nausea, diarrhea, and loss of appetite.
Some people may experience changes in behaviour, including nervousness or feeling depressed. Heat intolerance and electrolyte imbalances may also occur.
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 women who are pregnant or breast-feeding.
Creatine can cause water loss from the body and may cause dehydration. If you are already dehydrated, or if you are using medications that may cause water loss (such as diureticdiuretican agent that increases urine flows), consult your health care provider before taking creatine.
People taking diuretics, including but not limited to furosemide and hydrochlorothiazide, should avoid the use of creatine because of the risk of dehydration.
Creatine can interact with medications, food, and herbs. Check with your pharmacist for potential interactions with other herbs or medications you may be taking.
The following may interact with creatine:
- antidiabetes medications, including insulin
- ma huang (ephedra)
- nonsteroidal anti-inflammatory drugs (NSAIDS; e.g., ibuprofen, indomethacin, naproxen)
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.