The Organon group in the Netherlands were the first to isolate the hormone, identified in a May 1935 paper "On Crystalline Male Hormone from Testicles (Testosterone)". They named the hormone testosterone, from the stems of testicle and sterol, and the suffix of ketone. The structure was worked out by Schering's Adolf Butenandt, at the Chemisches Institut of Technical University in Gdańsk.
ED can also occur among younger men. A 2013 study found that one in four men seeking their first treatment for ED were under the age of 40. The researchers found a stronger correlation between smoking and illicit drug use and ED in men under 40 than among older men. That suggests that lifestyle choices may be a main contributing factor for ED in younger men.
Hypogonadism is a disease in which the body is unable to produce normal amounts of testosterone due to a problem with the testicles or with the pituitary gland that controls the testicles. Testosterone replacement therapy can improve the signs and symptoms of low testosterone in these men. Doctors may prescribe testosterone as injections, pellets, patches or gels.