Beyond decreased sperm production, another repercussion you don't see in the pop-up window ads asking "Is it low T?" is dependence: Once you begin taking testosterone, it's very difficult to stop because the body accommodates for the extra hormone and slows its natural production of it. In reality, replacing hormones is a lifelong commitment. Perhaps that's why some doctors are counseling patients to use caution and to look for other solutions before signing on for full testosterone therapy. Others see the gradual decrease in testosterone as a natural form of aging that we can combat by building muscle and reducing stress, even while we accept it and learn to live with it.