Creatine
Creatine occurs naturally in the body. Supplementation with creatine monohydrate has been shown to enhance physical performance.
Safety of creatine
As a dietary supplement, creatine monohydrate has an excellent safety record. A positive assessment by the European Food Safety Authority reflects the overwhelming scientific evidence that chemically pure creatine monohydrate is safe and has no side effects when used properly.
Supplementation
The only side effect that has been shown is a slight amount of weight gain. On one hand, this is caused by an increase in the accumulation of water in the muscles. On the other, this is caused by a gradual increase in muscle mass, which is exactly what many athletes want.
On the Internet, there are many reports that link creatine supplementation to stomach cramps, diarrhea, muscle cramps and an impairment of liver and kidney function. However, controlled scientific studies have not been able to confirm any of these side effects when pure creatine is taken at the recommended dosage with sufficient liquid. The vast majority of scientific studies refer to creatine monohydrate. Research on other forms of creatine has been limited.