Hypogonadism alone can cause erectile dysfunction, but it’s generally because the person also has other illnesses present in addition to low testosterone levels.
People with lowered testosterones levels can often have other medical conditions like diabetes, atherosclerosis, and high blood pressure.
Hypogonadism and all these conditions affect the blood flow toward the penis, leading to erectile dysfunction. For instance, blood flow is hampered in diabetes, which results in decreased blood supply to several organs, including the penis. The penis is unable to erect when there is insufficient blood supply.