Xtest Pro When trying to gain muscle mass by using over-the-counter supplements like creatine, watch the amount you take and for how long you take it. If you already suffer from kidney problems, ceatine could make it worse. In addition, they have been known to cause muscle compartment syndrome, heart arrhythmia, and muscle cramps. Young people in particular are at risk. Be sure you keep your creatine intake at or below suggested safety levels.