Testosterone was first synthesized in 1934, and physicians have argued about its usefullness in medicine ever since.  Julie Deardoff from the Chicago Tribune discussed the controversy.  Testosterone declines naturally after the age 30 and continues decreasing about 1 percent a year after that.  Most experts agree that men with testosterone levels less than 200 ng per hundred milliliters of blood should receive testosterone therapy.  Increasing levels above that is highly controversial.  testosterone supplements increase muscle mass and decrease fat, and often make middle-aged and older men feel better.  However, low testosterone often accompanies poor physical fitness and obesity, so following a healthy lifestyle might restore a normal testosterone level.  Most aging men need to exercise more and eat less.  If they do, testosterone will take care of itself.  (Chicago Tribune, March 14, 2012)