Smoking damages blood vessels, inhibiting blood flow throughout the body ... and I mean throughout the body. While studies have found that men with erectile problems only make up 20 percent of the general population, 40 percent of men with erectile problems are smokers. And a 2011 study of a group of male smokers with erectile problems found that 75 percent of them saw those erectile problems disappear after they quit.
Other hormone levels: Measurement of other hormones beside testosterone (luteinizing hormone [LH], prolactin level, and cortisol level) may provide clues to other underlying causes of testosterone deficiency and erectile problems, such as pituitary disease or adrenal gland abnormalities. Doctors may check thyroid levels in some individuals as both hypothyroidism (low thyroid function) and hyperthyroidism (overactive thyroid function) can contribute to erectile dysfunction.