If you have a "normal" t level, then extra t won't improve your health.
There are studies suggesting that higher t is associated w/less heart
disease, less cancer
, lower death rate, stronger bones, more muscle, less fat, stronger erections, greater sex
drive, brighter mood
, clearer thinking, etc, but these tend to be observational studies. Most recent one is http://bit.Ly/mhk22c.