Testosterone levels begin to decline in men beginning in their early 30’s. Most men maintain adequate levels of testosterone into their mid 40’s with some into their late 60’s. Men should be tested when they begin to show signs of testosterone deficiency. Even men in their 30’s can be testosterone deficient and show signs of bone loss, fatigue, depression, erectile dysfunction, difficulty sleeping and mental decline. Most men need to be tested around 50 years of age. It is never too late to benefit from hormone therapy. In addition, as men age and their testosterone level declines, estrogen levels may increase.