Testosterone replacement therapy has benefits for young men with what adverts
on the electric television machine call "low t," meaning "low testosterone," but a
larger group of beneficiaries is older men. Oddly this situation has not been studied
in the past.
"Hypogonadism -- a reduction or absence of hormones secreted by the testes-- is thought to affect 40 percent of men over the age of 45...."
http://www.huffingtonpost.com/entry/male-libido-gone-mia-there-may-be-a-fix-for-that_us_577678f3e4b0a629c1a994c7?section=