Creatine can cause individuals to gain water weight, as the supplement promotes fluid storage in the muscles, according to Men's Health Magazine. The magazine also explains that approximately two-thirds of individuals who take creatine gain approximately 0.8 to 2.9 percent body fat within one to two days of use.
SimplyShredded.com explains that creatine water weight gain is usually limited to skeletal muscles, but taking excess amounts of the supplement can also lead to abdominal bloating and cramping. Additional side effects of creatine can include nausea and diarrhea.
According to WebMD, creatine supplements help the body produce energy. Natural forms of creatine are found in certain high-protein foods, such as red meat and fish.