We all know what testosterone is.  It’s what makes our boy babies our boy babies.  It’s what makes men manly.  It’s a hormone naturally produced in our bodies and it fuels our sex drive, our body build and muscle strength, and our sperm count.  It’s what keeps us young looking, virile, and handsome even though the birthday candles are becoming too numerous to extinguish with one breath.

Testosterone is considered the male sex hormone while estrogen is its feminine counterpart.  Men’s bodies produce testosterone in the testes but women’s ovaries produce a little testosterone, too, just as men produce a bit of estrogen.

As men age, levels of testosterone fluctuate, beginning even before birth.  The first surge in a boy child’s testosterone level comes between weeks 7 and 12, during pregnancy, when development of internal and external genitalia begins.

Testosterone levels rise again during the first few weeks of a boy baby’s life.  The level of the hormone can climb to match that of a pubescent boy before dropping back to infancy level after the child reaches the age of 4 to 6 months.

The spike in testosterone level in early infancy produces no visible effect on the boy but many scientists speculate that it is during this phase of growth that the boy’s brain becomes masculinized, or “hard-wired” to be male.

Testosterone levels spike again during puberty, when visible changes do take effect, and hormone levels reach their highest in the last stages of adolescence, when a boy’s body transforms into that of a young man.

A decline in a man’s level of testosterone begins around the age of 40, perhaps generating the puzzling behavior often described as “middle-age crazy.”  In addition to doing wild and uncharacteristic things, a man may begin to consider the merits of testosterone replacement therapy at around this time in life, too.

Repeated studies have shown, however, that supplemental testosterone in otherwise healthy but aging men does nothing more than increase the level of the hormone in the bloodstream.  It doesn’t return youth, vitality, vigor, nor does it ensure longevity and virility into old age.  And it comes with some adverse side effects that increase the risk of sleep apnea and heart disease.

Perhaps a more reliable way to stay young, active, and feeling like you want to live forever is to forget the testosterone supplements and learn to enjoy an active lifestyle that includes a healthy diet and about a half hour of pleasant exercise every day.