If testosterone is reduced, why don't you replace it? Not too fast. A low testosterone level alone does not require therapy. Testosterone replacement therapy may have side effects, and also the long term dangers and benefits are not known. Just guys with symptoms of low blood and testosterone levels which affirm this as the reason for symptoms should think about testosterone replacement. Talking with your doctor is the only method to learn if testosterone treatment is ideal for you. Subtle Symptoms of Low Testosterone The symptoms of low testosterone are sometimes obvious, but they also can be subtle. Testosterone levels decline naturally in men as they age over decades. But certain conditions can also lead to an abnormally low level. Symptoms of low testosterone include: Low sex drive (libido) Erectile dysfunction Fatigue and poor energy level Decreased muscle mass Body and facial hair loss Difficulty concentrating Depression Irritability Low sense of well-being...