Who knew low testosterone could cause so many symptoms?

A great article was posted on http://www.knowledgecloset.com/2010/05/14/what-are-the-symptoms-of-low-testosterone/ the author states

When testosterone levels decrease below the normal range, men experience many of the following common symptoms:

Low sex drive
Increased irritability or depression
Fatigue
Erectile dysfunction (ED)
Inability to concentration
Reduced muscle mass and strength
Decreased bone density; osteoporosis

The most common symptoms I have seen in my male relatives and friends who have suffered from low testosterone levels have been increased irritability or depression and fatigue. These symptoms have quickly disappeared after seeing the doctor and being proscribed medication.