Breastfeeding while using this supplement is also not recommended. If you are using this steroid, you should have routine tests (including blood tests) to determine its effectiveness and to detect any harmful effects it is having on your health. If they are prescribed by a doctor, one can be reasonably sure that the substance you are injecting is a pure form of testosterone enanthate. However, because of the controlled nature of this supplement, a black market for it has emerged. Be wary Nandrolone Decanoate using Deca Durabolin of this steroid which are from dubious sources, Decabolin, as they may be impure and harmful to your health. Be critical of who and where you purchase this substance from. While this brief article is no replacement for actual medical advice from a professional doctor, it has hopefully provided some useful background information on testosterone enanthate. This supplement (steroid) has pronounced effects on the body and carries with it the possibility of a number of side effects. Conduct your own research and ask your medical professional for more information.