Do testosterone boosters work? What is testosterone you ask? Testosterone is what makes a man, a man. All the changes that you see when a boy turns into a man, like the deeper voice is all the work of testosterone. Do you the symptoms of low testosterone level? Well if you experience low sex drive, mood swings, fatigue, weight gain, sleep problems, erctile dysfunction then yes you might have low testosterone level. How do you keep the level high? Well, click the link to know more.