Low levels of testosterone have been implicated in a host of life-threatening health problems. Maintaining normal testosterone levels is one of the most important steps you can take to regain your health and improve your performance. If you're over 40, odds are you're already starting to feel the debilitating effects of low testosterone. Research shows that by the time they are 60 years old, men typically produce 60% less testosterone than they did at age 20. With this drastic reduction comes several well documented problems - from the blues and cognitive impairment to reduced sex drive and abdominal weight gain. Normal testosterone has been associated with maintaining a healthy cardiovascular system.