Nitric Muscle Fuel Building muscle does not always have to mean having a hard six pack or huge biceps. All different kinds of muscle-building programs exist.Nitric Muscle Fuel If you choose to supplement your muscle-building attempts with creatine, be careful, especially if you use this substance long-term. If you have any kidney conditions, do NOT use creatine! Creatine can also lead to heart arrhythmia, cramps or muscle compartment syndrome. Creatine should be especially avoided by the young. Always take nutritional supplements cautiously and only as directed.