By the time Dan hit 57, he didn't recognize himself. He was always tired, fell asleep after dinner and was angry all the time.
"My libido was less and I was beginning to have a loss of erection while having sex, but I thought that was part of the normal aging process," said Dan, who did not want his real name to be used.
"I had just changed doctors and he asked me, 'Are you more grumpy and less interested in things like sex?'" Dan, now a 60-year-old California counselor, said.
"Yeah, I am more grumpy, get less enjoyment out of life and certainly am having less sexual activity with my wife of 40 years," Dan answered. "I had excellent health all my life and he said there was a name for it -- male menopause."
The doctor ordered a series of blood tests and found Dan had low levels of testosterone. "My levels were in the basement," he said.
Dan, according to his doctor, has andropause, what is now euphemistically being called low-T syndrome.
Television ads for low-T syndrome have cropped up on prime-time nightly news programs, joining direct-to-consumer drug ads for erectile dysfunction, or "ED," as well as other aging ailments such as high cholesterol, enlarged prostates and dry eyes.
Andropause is a "term of convenience" in describing the complex symptoms in aging men with low testosterone levels, according to one study at the University of Toronto Department of Medicine.
Some studies show only 25 percent of all men with low testosterone levels ever experience symptoms such as Dan's, as well as bone loss and fracture, sleep disturbances and lethargy.
The very existence of andropause is contentious and large-scale studies on hormone treatment are only a decade old. Many say the underlying cause of some men's complaints are part of the normal aging process.
Two Canadian studies cited by the National Institutes of Health illustrate the debate on low testosterone and its treatment.
Dr. Richard Casey, director of the Male Health Centers in Oakville, Ont., argues that andropause is primarily market-driven, "largely promoted by industry, accepted by a handful of physicians and embraced by some patients who are looking for an antidote to aging."
"We need to resist the marketing efforts and consider the science," writes Casey. "The range of normal testosterone levels is quite broad; levels depend on time of day and no consensus exists on what measurement of testosterone correlates best with symptoms or treatment success."
But Dr. Alvaro Morales of Queens University in Ontario supports the concept of "testosterone deficiency syndrome" (TDS) and advocates well-monitored therapy.
"The absurd view that TDS is an invention of industry blatantly and conveniently ignores medical observations and reports going back 500 years and accelerating since the mid 20th century," writes Morales in his study. "It does not merit further discussion."
"Male menopause is real," said Jed Diamond, a psychologist and author of a series of books on the topic, including, "Irritable Male Syndrome."
"I describe it as adolescence, the second time around," he said. "Everybody goes through it, just as no one can say I didn't go through puberty. Some have a fairly easy time and, for some, it's more difficult."