David Baxter PhD
Late Founder
Look out, men: Testosterone is under attack
By Richard Conniff, MensHealth
Aug 19, 2007
A phenomenon called a xenobiotic attack is meddling with your manhood
In 2003, professional golfer Shaun Micheel took his game to a new level. He won the PGA Championship on the 72nd hole with his 21st birdie of the tournament. Then everything seemed to fall apart.
"I lost my drive. I didn't enjoy practicing anymore. If I made a couple of bogeys, I just wanted to go home," he said at the time. It was more than a slump. He barely even showed up on the professional circuit the following year. At first he thought it was depression. "I seemed to be tired all the time, and irritable. I wasn't myself."
But in April 2005, a blood test showed that, at the age of 36, Micheel had the testosterone level of a 70-year-old. His doctor had him rub a hormone-replacement gel onto his biceps each morning. By September his testosterone level was back to normal.
It wasn't a miracle cure. He still hasn't won another major tournament, though he did manage a second place finish last year. But Micheel is working his way back up the list of money winners. More important, both he and his wife say testosterone has given him back his old, upbeat personality.
Good news for him, but what about the rest of us? Some scientists now wonder if a lot of other "walking, talking, normalish guys," as one urologist put it, are also experiencing a fading of the hormonal basis of masculinity, leaving them feeling less like the men they used to be, less than their fathers were in their time.
Falling testosterone levels
Most men can expect their testosterone levels to drop by about 1 percent a year beginning in their 50s. So a man in his 70s might have only half the testosterone he had when he was 25. But researchers behind the Massachusetts Male Aging Study ? which has been tracking behavioral and physiological traits for 1,709 men born between 1916 and 1945 ? noticed something strange. Men born more recently had T levels that were surprisingly low. The 60-year-old in 2003 had about 15 percent less testosterone than the 60-year-old in 1988, according to Thomas G. Travison, Ph.D., lead author of the testosterone study. Sixty was looking like the new 70. Had something happened? Could we be in the middle of some broad biological or environmental change affecting all men simultaneously?
No one was suggesting that men rush out to get their testosterone levels checked (though, okay, I did), much less consider testosterone therapy (and, yes, I am considering it). As one endocrinologist put it, "You need to see more than one study from more than one laboratory before you start waving your arms and shouting alarm."
But the Massachusetts results marked a turning point: Testosterone is no longer just a hot topic for misguided weight lifters or baby boomers with delusions of eternal youth. It's something the average aging male will need to think about, starting with a few testosterone basics.
What makes us men
Testosterone is literally what makes us men. Delivery of the right amount at the critical moment shifts development of a fetus away from the basic human blueprint, which is female, and onto the path to masculinity. A surge in testosterone (from the testes ? hence the name) in adolescence boosts us into manhood. And for the rest of our lives, testosterone, or the lack of it, seems to play a key role in muscle strength, lean body mass, bone density, mental sharpness, and sex drive ? the things that often make us feel best about who we are.
Despite testosterone's explosive reputation, there's no solid evidence that it causes aggression or violence. On the contrary, heightened testosterone is often associated with self-confidence and social success. Testosterone levels typically increase to ready us for a challenge, whether it's a football game or a chess match. Testosterone also rises after a victory, causing an increase in confidence that often leads to even more victories, the so-called winner effect. Who would want less of a hormone like that?
And yet the quantity of the stuff, even in healthy young men, is astoundingly small. Most doctors measure total testosterone as the starting point, and for American men under the age of 40, the normal range is 300 to 1,000 nanograms per deciliter of blood. (That's what "ng/dl" means on your medical laboratory report.) A nanogram is a billionth of a gram, and a deciliter is a 10th of a liter. Or, to put it in layman's terms, not bloody much. If you somehow managed to collect all the testosterone from your entire body, it would barely fog the bottom of a shot glass.
It's in the blood
But it gets more complicated. Testosterone occurs in the blood in three forms.
About 40 percent of total testosterone is tightly bound to sex hormone?binding globulin, or SHBG, meaning it's not readily available for use by the body. In fact, nobody knows for sure what function SHBG-bound testosterone performs.
By Richard Conniff, MensHealth
Aug 19, 2007
A phenomenon called a xenobiotic attack is meddling with your manhood
In 2003, professional golfer Shaun Micheel took his game to a new level. He won the PGA Championship on the 72nd hole with his 21st birdie of the tournament. Then everything seemed to fall apart.
"I lost my drive. I didn't enjoy practicing anymore. If I made a couple of bogeys, I just wanted to go home," he said at the time. It was more than a slump. He barely even showed up on the professional circuit the following year. At first he thought it was depression. "I seemed to be tired all the time, and irritable. I wasn't myself."
But in April 2005, a blood test showed that, at the age of 36, Micheel had the testosterone level of a 70-year-old. His doctor had him rub a hormone-replacement gel onto his biceps each morning. By September his testosterone level was back to normal.
It wasn't a miracle cure. He still hasn't won another major tournament, though he did manage a second place finish last year. But Micheel is working his way back up the list of money winners. More important, both he and his wife say testosterone has given him back his old, upbeat personality.
Good news for him, but what about the rest of us? Some scientists now wonder if a lot of other "walking, talking, normalish guys," as one urologist put it, are also experiencing a fading of the hormonal basis of masculinity, leaving them feeling less like the men they used to be, less than their fathers were in their time.
Falling testosterone levels
Most men can expect their testosterone levels to drop by about 1 percent a year beginning in their 50s. So a man in his 70s might have only half the testosterone he had when he was 25. But researchers behind the Massachusetts Male Aging Study ? which has been tracking behavioral and physiological traits for 1,709 men born between 1916 and 1945 ? noticed something strange. Men born more recently had T levels that were surprisingly low. The 60-year-old in 2003 had about 15 percent less testosterone than the 60-year-old in 1988, according to Thomas G. Travison, Ph.D., lead author of the testosterone study. Sixty was looking like the new 70. Had something happened? Could we be in the middle of some broad biological or environmental change affecting all men simultaneously?
No one was suggesting that men rush out to get their testosterone levels checked (though, okay, I did), much less consider testosterone therapy (and, yes, I am considering it). As one endocrinologist put it, "You need to see more than one study from more than one laboratory before you start waving your arms and shouting alarm."
But the Massachusetts results marked a turning point: Testosterone is no longer just a hot topic for misguided weight lifters or baby boomers with delusions of eternal youth. It's something the average aging male will need to think about, starting with a few testosterone basics.
What makes us men
Testosterone is literally what makes us men. Delivery of the right amount at the critical moment shifts development of a fetus away from the basic human blueprint, which is female, and onto the path to masculinity. A surge in testosterone (from the testes ? hence the name) in adolescence boosts us into manhood. And for the rest of our lives, testosterone, or the lack of it, seems to play a key role in muscle strength, lean body mass, bone density, mental sharpness, and sex drive ? the things that often make us feel best about who we are.
Despite testosterone's explosive reputation, there's no solid evidence that it causes aggression or violence. On the contrary, heightened testosterone is often associated with self-confidence and social success. Testosterone levels typically increase to ready us for a challenge, whether it's a football game or a chess match. Testosterone also rises after a victory, causing an increase in confidence that often leads to even more victories, the so-called winner effect. Who would want less of a hormone like that?
And yet the quantity of the stuff, even in healthy young men, is astoundingly small. Most doctors measure total testosterone as the starting point, and for American men under the age of 40, the normal range is 300 to 1,000 nanograms per deciliter of blood. (That's what "ng/dl" means on your medical laboratory report.) A nanogram is a billionth of a gram, and a deciliter is a 10th of a liter. Or, to put it in layman's terms, not bloody much. If you somehow managed to collect all the testosterone from your entire body, it would barely fog the bottom of a shot glass.
It's in the blood
But it gets more complicated. Testosterone occurs in the blood in three forms.
About 40 percent of total testosterone is tightly bound to sex hormone?binding globulin, or SHBG, meaning it's not readily available for use by the body. In fact, nobody knows for sure what function SHBG-bound testosterone performs.
but I am here too and I hate oatmeal!
