Sustanon 100 Injection is a medicine used in the treatment of male hypogonadism caused due to low testosterone levels. It is only prescribed to men with known medical conditions. It helps in restoring the level of testosterone in the male body. Sustanon 100 Injection is injected directly into the skin or muscles under the medical supervision of a doctor. The dose and how often you take the injection depends on what you are using it for. Your doctor will decide how much you need to improve your symptoms. You should take this medicine for as long as it is prescribed for you. The most common side effects of this medicine include acne, breast enlargement in male, voice change, and injection site reactions (pain, swelling, redness). If these bother you or appear serious, let your doctor know. There may be ways of reducing or preventing them. Some side effects may mean you should stop taking this medicine shortness of breath, frequent or persistent erections, and low sperm count. Before taking this medicine, tell your doctor if you have ever had high blood pressure, heart attack, and stroke. Your doctor should also know about all other medicines you are taking as many of these may make this medicine less effective or change the way it works. Your doctor might perform regular blood tests to keep track of testosterone, and prostate-specific antigen (PSA) levels.