Male hypogonadism, as it's called in the medical community, occurs when the testicles do not produce enough testosterone, the hormone that plays a key role in masculine growth and development.
Symptoms of male menopause are fatigue, mood swings, decreased desire for sex, hair loss, lack of concentration and weight gain.
Experts estimate that more than 5 million men are affected but the number may be considerably higher since symptoms are frequently ignored.
When hormone levels drop, men can experience significant mental and physical changes.
"This is a highly prevalent disorder. Unfortunately, we estimate that 95 per cent of cases are undiagnosed and therefore untreated. When ignored, symptoms can seriously disrupt one's quality of life," said Robert Brannigan, MD, urologist at Northwestern Memorial Hospital.
Michael Andruzzi, a 40-year-old man diagnosed with male hypogonadism and a patient at Northwestern Memorial said, "My body was telling me that something wasn't right. I was always tired, it didn't matter how much sleep I got, I constantly wanted to take a nap."
Brannigan explains hormone variations are a normal aspect of getting older.
"In females, ovulation comes to an end and hormone production declines in a relatively quick period of time, whereas men experience hormone shifts more slowly, with testosterone levels dropping around one percent each year beginning in a man's late thirties," added Brannigan.
Brannigan said at the age of 70, the reduction in the male testosterone level could be as high as 50 per cent or more compared to baseline levels, but notes that ageing men are not the only ones at risk.
A number of genetic causes can impact males from birth and are usually diagnosed with failure to progress normally through puberty during the teenage years.
Treatment options for male hypogonadism include hormone replacement therapy (HRT) via absorbable pellet implants, topical gels, patches, and injections.
Through HRT, doctors can restore sexual function and muscle strength.
In addition, men often experience an increase in energy and an improved overall sense of well-being.
"Once I began treatment, I felt better very quickly. My energy level shot back up, I regained strength and felt I could concentrate much better," said Andruzzi.
"We are seeing more men affected by male hypogonadism than we saw ten years ago. However, many men continue to suffer in silence due to a lack of awareness surrounding the disorder," Brannigan said.
Because male hypogonadism can significantly impact the quality of one's life, it's important that men pay attention to their body and openly discuss symptoms with their physician in order to prevent overlooking the cause and avoid missing an opportunity for appropriate therapy.
Although research to determine the exact association continues, doctors also warn that male hypogonadism has been linked to chronic medical conditions such as high cholesterol, diabetes and cardiovascular disease.
It's also closely associated with infertility.
"This disorder is not something that should be ignored," said Brannigan, who is working to educate patients and physicians about the symptoms and treatments available in order to ensure therapies are made available to men in need.
Male hypogonadism is most commonly diagnosed through a simple blood test.
Brannigan notes hormone replacement therapy is not appropriate for all patients especially those with history of prostate and breast cancer and men trying to conceive.