The control and coordination of the human body is done by the Central Nervous System (CNS), either with the help of neuro-muscular impulses or with the use of hormones. The erection of the penis is mediated by the hormones Testosterone and Androgen. Both of these hormones are synthesized by the Adrenal glands. The chemical substances that constitute alcohol and cigarettes have active molecules that bind with the CNS and inhibit the production of the sexual hormones and, hence, result in erectile dysfunction. Hence, it should be borne in mind that though the consumption of these products gives initial pleasure, yet in the long run it can adversely affect the well being of the person.

The hormones that the body synthesizes are, in fact, biological enzymes. The binding sites of the various medicines that a person takes interact with the active sites of the enzymes. This alters the nature of the enzyme and, hence, its molecular activity. Thus, it does not bind to the target site, in this case, the adrenal glands, for which it was intended. Hence, it affects the production of sexual hormones and acts as a precursor for erectile dysfunction.

It has been observed in experiments that diabetics have significantly higher chances of getting affected with impotency. However, the chances of its prevalence depends on the type of diabetes, i.e. whether it is type I or type II diabetes. Diabetes results in reduced amount of glucose in the blood stream which reaches the penis. Hence, sufficient energy is not available for the muscles to make the penis erect. High blood pressure results in lack of proper blood supply to the penis to get erect. Thus, it is advisable that the concerned person gets himself diagnosed for diabetes and hypertension and get proper advice from the doctor.

It has been long known that stress makes a person prone to many diseases like hypertension, heart disease and diabetes. As it was mentioned before, diabetes and hypertension are the main causative factors for erectile dysfunction, the causative factor of both being stress and depression. Stress affects our body both physically and psychologically.

This results in the secretion of hormones cortisol and adrenaline. Adrenaline leads to constriction of blood to other organs to direct it to the organ that requires it the most to combat the cause of stress. This lack of blood supply, caused by stress, results in erectile dysfunction.

Vascular diseases are those diseases that affects the blood vessels, thereby, resulting in lack of proper blood supply to the penis and, thus, result in erectile dysfunction.

When an incision is made on the prostate glands as a remedy for prostate cancer, there are high possibilities of the nerves, which control the sexual activity of man, being cut, thereby resulting in ED.

The main causative factor for erectile dysfunction is lack of proper blood supply to the penis, which may be caused by the various reasons mentioned before.