well, here are some articles:
check out this link first:
http://www.alt-support-impotence.org/hormone_charts.htm
from what i get from these articles, and others that i've read is that there is a decline after the early twenties, followed by a rise in your late twenties, before more anothe steady decline.
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Male Menopause
Menopause for men, you might ask? Unfortunately, yes! Andropause – the male menopause - is more gradual than that experienced by women, but it is just as real. It often starts as early as age 35. Because it is so gradual, men often reach their mid-forties before they are even noticing some of the signs and symptoms.
Andropause, like menopause, is caused by a decline in hormones. (Primarily testosterone and the secondarily growth hormone, along with DHEA) On the average, a man’s testosterone level begins to decline at a rate of 1% per year after age 40. It is estimated that 20% of men aged 60 to 80 years have levels below the lower limit of normal. The diagnosis of low testosterone levels is based on the presence of signs or symptoms and must be confirmed by laboratory testing. The extent to which declining hormone levels cause men to age is dependent on lifestyle issues of diet, exercise and stress.
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Unlike women experiencing menopause, in men, hormone levels decline
slowly and symptoms may or may not occur. Testosterone levels in men often
begin to decline around age 30, and drop approximately 10 percent each decade.
Often, the patient dismisses these symptoms as a regular part of the aging
process. However, thanks to the aging "baby boomers" andropause will be a
significant health concern to a huge sector of the population wanting a longer
and healthier life.
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on GH
In humans, the amount of human growth hormone after age 30 declines about 14% per decade, so that total daily human growth hormone production is reduced dramatically with age. In numerical values, we produce on a daily basis about 500 micrograms of human growth hormone at age 20, 200 micrograms at age 40, and 25 micrograms at age 80. At age 40 our human growth hormone production is only 40% of what we produced at age 20. The fall in IGF-1 levels with age is identical to the decline of growth hormone.