Is creatine dangerous for the kidneys?
To store ingested creatine and that produced by the liver, our body transforms it into phosphocreatine, which is used to produce ATP. A co-product of this last step is creatinine, which will be eliminated by the kidneys. Degraded kidney function therefore does not allow this creatinine to be properly eliminated, which is why the creatinine level is often used as a marker of kidney health.
But all available studies have shown no harm in healthy people, with creatine intake simply naturally increasing the amount of creatinine eliminated. In people with kidney problems, studies have also shown no short-term problems, but longer-term data are lacking.
In addition, athletes also often have a higher blood creatinine level than sedentary people, even without supplementation. This is the natural consequence of greater muscle mass and concerns more strength sports than endurance sports. In reality, there is therefore no problem as long as the values do not exceed the upper limits. Otherwise, you should talk to your doctor to analyze the other criteria of kidney health.