Who told you that your doctor? You can take creatine and steroids no problem with only one kidney as long as you watch your blood pressure. I guess you eat a low protein diet too? Cause protein puts just as much stress on kidneys as creatine and steroids would or do.
Read the packet of any creatine product. Says dont take if kidney problems.
My Urologist told me to avoid it. It was the catalyst for me going into hospital. I never knew i had kidney problems. Took creatine. 3 weeks later was admitted to hospital for over a week.
Why risk it for 10kg extra on my bench press?
Also i do eat low protein diet. I just dont want to risk it and abuse or risk abusing my health.
When i used to drink i found that over time it make my kidney sorer and sorer until it got too bad after a night out i just quit drinking