Erection problems can be caused by:
Diabetes, especially if you have type 2
Blockages in the blood flow to the penis
Atherosclerosis, or hardening of the arteries leading to the penis
Damage to arteries or nerves after radiation treatment
Leaky veins
Low levels of the male hormone testosterone or other hormonal disturbances
Conditions or behaviors that increase the risk of vascular disease, such as smoking, high blood pressure, diabetes, and high cholesterol or the medications to treat these and other disorders