Erectile Dysfunction

Erectile dysfunction (ED), or impotence, is the inability to get or keep an erection (hard penis) for enough time to have satisfactory sex. To get and maintain an erection, blood must be able to flow into and stay in the penis. Men commonly have problems with their erections once in a while. But if ED occurs frequently, medical therapy may be helpful. About 30 million men in the United States have ED. It can happen at any age, but is more common in men older than 65. ED is treatable at any age. ED can be a symptom of early blood vessel disease in other locations in the body.

The evaluation of ED starts with a careful medical history, including history of sexual function, medications, illnesses, or injuries that could cause ED; and any recent physical or emotional changes. The evaluation typically includes a physical exam, urinalysis, and a measurement of early morning testosterone levels. The doctor may also order blood tests for luteinizing hormone (LH), follicle stimulating hormone (FSH), the hormone prolactin, fasting blood glucose (sugar), and lipids (blood fats such as cholesterol). To obtain more information about patient man’s general and endocrine (hormonal) function, the doctor may also test for liver, kidney, and thyroid disorders.

Causes of erectile dysfunction

Any physical condition that interferes with sexual desire (libido), blood flow, or nerve signals to the penis can cause ED. The most common causes are conditions that affect blood vessels and blood flow in the penis, such as hardening of the arteries (atherosclerosis) that is linked to diabetes, obesity, smoking, high blood pressure, and high cholesterol. Medications (antidepressants, sleeping pills or tranquilizers, and drugs to treat high blood pressure, pain, or prostate cancer), alcohol, tobacco, and illegal drugs commonly cause ED.

Other common causes for ED include:

  • Brain diseases (such as stroke)
  • Damage to the nerves that deliver signals from the brain and spinal cord to the penis due to diabetes, multiple sclerosis, spinal cord injuries, pelvic or prostate surgery, radiation therapy, or pelvic or bicycle seat pressure trauma
  • Hormone imbalances such as low testosterone, high prolactin, and abnormal thyroid hormone levels
  • Chronic kidney and liver disease, which affect blood vessels, nerves, and hormone levels
  • Rarely, scarring of the penis that causes a severe curving (Peyronie’s disease) during erections

Treatment of erectile dysfunction

The treatment of ED depends on the cause and seriousness of the condition. For some men, adopting a healthier lifestyle, such as quitting smoking, exercising regularly, eating a healthy diet, reducing stress, and/or limiting alcohol, may be all that is needed to remedy the problem. But for those who need more intensive treatment, options include

  • Pills. Three effective drugs are available—sildenafil, vardenafil, and talafadil. All three work by increasing blood flow to the penis during sexual stimulation.
  • Direct penis therapies. Medications that can be injected into the penis or inserted into the urethra (the tube that carries urine and semen outside the body) to increase blood flow. These may work when pills do not.
  • Testosterone replacement therapy. In men with low testosterone levels and hypogonadism, testosterone can be replaced through injections, skin patches, gels, or tablets placed between the cheek and gums. Combination medical therapy. Some men who don’t respond well to any one of the first three therapies alone may have a better response with a combination of a pill plus direct penis therapy and/or, if blood testosterone levels are low, testosterone replacement therapy.
  • Vacuum device. This is an external plastic cylinder and gentle hand-held vacuum pump that pulls blood into the penis. Then an elastic ring is placed around the base of the penis to prevent blood from flowing from the penis back into the body.
  • Surgery. Penile implants (rigid or inflatable types) are used for the rare patient who doesn’t respond well to other therapies. Implants are expensive, can lead to infections, and may not work in the long term. Surgery is rarely used to correct a blockage of penile blood flow; the best candidates are young men with limited blockage.
  • Psychological counseling. If a relationship or an emotional problem is causing ED, a sex therapist may be needed.


Bradley Anawalt, MD
University of Washington

Alvin Matsumoto, MD
VA Puget Sound Health Care System

Last review: May 2013