the kidneys are responsible for cleansing the Creatine in your blood.Thats why blood tests are required before and after cycles, for example High creatinine levels in urine are often caused due to strenuous exercise, muscle injury, more so - crushing injuries, burns, pregnancy, hypothyroidism or carbon monoxide poisoning. It is a common indicator of serious damage to the kidney or presence of some disease. If the levels are on the higher side, the most common symptoms include dehydration, fatigue, shortness of breath, confusion or other non specific symptoms as well.If this problem continues expect damage to occur leading to kidney failure.