Men do experience a decline in the production of the male hormone testosterone with aging, but this also occurs with conditions such as diabetes. Along with the decline in testosterone, some men experience symptoms that include fatigue, weakness, depression, and sexual problems.
http://www.medicinenet.com/male_menopause/article.htm
Debunking the male menopause myth. The term male menopause is sometimes used to describe decreasing testosterone levels or a reduction in the bioavailability of testosterone related to aging. Female menopause and so-called male menopause are two different situations, however.
http://www.mayoclinic.org/healthy-lifestyle/mens-health/in-depth/male-menopause/art-20048056
Also referred to as low-T, andropause, or (its medical name) late-onset hypogonadism, the idea behind the concept of male menopause is that the decline in testosterone levels that occurs as men age may be producing a characteristic and potentially treatable set of symptoms.
http://www.medicinenet.com/male_menopause/article.htm
After a full year without a period, you can say you have been “through menopause,” and perimenopause is over. Postmenopause follows perimenopause and lasts the rest of your life. The average age of a woman having her last period, menopause, is 51. But, some women have their last period in their forties, and some have it later in their fifties. Smoking can lead to early menopause. So can some types of operations.
https://www.nia.nih.gov/health/publication/menopause
The relationship of these symptoms to decreased testosterone levels is still controversial. Unlike menopause in women, when hormone production stops completely, testosterone decline in men is a slower process. The testes, unlike the ovaries, do not run out of the substance it needs to make testosterone. A healthy man may be able to make sperm well into his 80s or later. However, as a result of disease, subtle changes in the function of the testes may occur as early as age 45 to 50 and more dramatically after the age of 70 in some men.
http://www.webmd.com/men/guide/male-menopause
So what's the best way to refer to so-called male menopause? Many doctors use the term andropause to describe aging-related hormone changes in men. Other terms include testosterone deficiency syndrome, androgen deficiency of the aging male and late-onset male hypogonadism.
http://www.mayoclinic.org/healthy-lifestyle/mens-health/in-depth/male-menopause/art-20048056
Because men do not go through a well-defined period referred to as menopause, some doctors refer to this problem as androgen (testosterone) decline in the aging male -- or what some people call low testosterone.
http://www.webmd.com/men/guide/male-menopause
Because men do not go through a well-defined period referred to as menopause, some doctors refer to this problem as androgen (testosterone) decline in the aging male, or what some people call low testosterone.
http://www.medicinenet.com/male_menopause/article.htm
A healthy male may be able to make sperm well into his eighties or longer. However, as a result of disease, subtle changes in the function of the testes may occur as early as 45 to 50 years of age, and more dramatically after the age of 70 in some men. To make the diagnosis of male menopause, the doctor will perform a physical exam and ask about symptoms.
http://www.medicinenet.com/male_menopause/article.htm
Menopause is a normal part of life, just like puberty. It is the time of your last menstrual period. You may notice changes in your body before and after menopause. The transition usually has three parts: perimenopause, menopause, and postmenopause.
https://www.nia.nih.gov/health/publication/menopause
male menopause what age
Male menopause starts as early as age 45 to 50 and after the age of 70. Male menopause can be as early as age 45 to 50, and more dramatically after the age of 70 in some men.  