It is estimated that approximately 20 million American males are suffering from erectile dysfunction. The causes of this erectile dysfunction epidemic are varied and include prescription drugs, testosterone decrease and circulatory insufficiency from clogged arteries.
Regarding circulatory insufficiency, a study published in the American Journal of Epidemiologyshowed that erectile dysfunction correlates with high total cholesterol and low HDL, the healthy cholesterol. Atherosclerotic plaque has an affinity to accumulate in penile arteries as much as it does in coronary arteries. This condition can be treated with penis bypass surgery, similar to coronary bypass surgery where the blood is rerouted around the clogged area.
Pharmaceutically induced erectile dysfunction can be caused by taking antihypertensive, antidepressant, diuretic or tranquilizing medications.
Age related testosterone decline is also implicated in erectile dysfunction, for these men sex drive is a fond memory. Low testosterone may be characterized by the following: inability to achieve an erection, diminished libido, and reduced ejaculate volume.
Testosterone is a minor steroid hormone which functions to promote bone formation and muscle growth in the body. Minor and major hormones communicate with each other constantly and are secreted in response to our constantly changing lifestyle and environmental signals. The three major hormones are; adrenalin, cortisol and insulin. Minor hormones are the estrogens (grouped as estriol, estrone and estradiol), progesterone, testosterone and DHEA. These hormones are considered minor because lack of them will not kill you but this lack can make your life miserable.
In men, testosterone affects the quality of erections, men’s emotional well-being and vitality, and protects the male heart. In addition, it improves oxygen uptake by the cells, revitalizes the body, improves concentration and mood and helps control blood sugar in both sexes. Women produce testosterone in the ovaries and adrenal glands, men produce it in the testes and adrenal glands. As men and women age, stressed adrenal glands are not always prepared to increase production of minor hormones.
A 2006 study published in the Asian Journal of Androl shows that the plant extract Icariin from Horny Goat Weed (Epimedium spp) can improve the overall health of male reproductive organs, increase overall levels of circulating testosterone and increase bone formation while supporting optimal function of penile tissue.
 Mind W, et.al. Total Cholesterol and High Density Lipoprotein Cholesterol as Important Predictors of Erectile Dysfunction. Am J Epidemiol 1994; 140:930?