Low testosterone is a possible contributor to erectile dysfunction (ED), but it is not the most common cause. Low testosterone more often reduces sexual desire and arousal. ED can also result from reduced blood flow, diabetes, high blood pressure, obesity, smoking, medication side effects, nerve problems, anxiety, or depression.
| Question | Short answer |
|---|---|
| Can low testosterone cause ED? | Yes, in some men |
| Is low testosterone the usual cause of ED? | No. Blood-vessel, metabolic, medication-related, and psychological causes are common |
| Does testosterone replacement always fix ED? | No. It may improve libido and sexual activity, but erection problems can remain |
| How is low testosterone confirmed? | Symptoms plus consistently low testosterone on 2 separate early-morning blood tests |
How Does Low Testosterone Affect Erections?
Low testosterone can reduce sexual desire and make arousal more difficult. A man with low testosterone may also have:
- Less interest in sex
- Fewer spontaneous or morning erections
- Difficulty becoming aroused
- Erectile dysfunction
- Fatigue, low mood, reduced muscle mass, or infertility
An erection also depends on healthy blood vessels, nerves, brain signals, and psychological factors. As a result, low testosterone and ED can occur together without low testosterone being the only cause.
Is ED More Likely to Be Caused by Low Testosterone or Poor Blood Flow?
Poor blood flow is often a more important cause of ED. Diabetes, high blood pressure, high cholesterol, obesity, smoking, atherosclerosis, and cardiovascular disease can damage or narrow the blood vessels needed for an erection.
Some medicines, pelvic surgery, nerve disorders, stress, anxiety, and depression can also cause or worsen ED.
New or worsening ED may be a reason to check for cardiovascular risk factors and diabetes, not only testosterone deficiency.
Can Testosterone Replacement Therapy Treat ED?
Testosterone replacement therapy can help some men with confirmed hypogonadism, but it is not a reliable treatment for ED on its own.
Testosterone replacement may improve sexual desire and sexual activity in men with hypogonadism. Its effect on erections is less consistent. In one randomized trial, adding testosterone to optimized sildenafil treatment did not improve erectile function more than sildenafil alone.
Doctors may consider testosterone treatment when:
- Symptoms suggest testosterone deficiency.
- Blood tests show consistently low testosterone.
- Other causes of ED have been assessed.
- The patient understands the possible benefits and risks.
Do not use testosterone bought online or from an unregulated clinic without medical supervision. Testosterone therapy can affect fertility and requires monitoring. The Endocrine Society recommends diagnosing hypogonadism only when symptoms occur alongside consistently low testosterone results.
How Is Low Testosterone Tested?
Low testosterone is confirmed through symptoms and 2 total testosterone measurements taken on separate occasions in the early morning. One low result does not establish the diagnosis. Testosterone levels can change with the time of day, illness, sleep, medications, and other health conditions.
A clinician may also assess:
- Free testosterone when appropriate
- Luteinizing hormone and follicle-stimulating hormone
- Blood sugar or diabetes markers
- Cholesterol and cardiovascular risk
- Medication side effects
- Sleep apnea, obesity, depression, or chronic illness
What Should You Do If You Have ED and Suspect Low Testosterone?
Arrange a medical evaluation if ED persists, worsens, or occurs with low sex drive, fatigue, infertility, loss of muscle, or fewer morning erections. A clinician can test testosterone correctly while also checking for more common contributors, including diabetes, high blood pressure, medication effects, and vascular disease.
Treatment may include lifestyle changes, management of an underlying condition, an ED medicine such as a PDE5 inhibitor, counseling for performance anxiety, or testosterone therapy when deficiency is confirmed. NIDDK notes that clinicians may use testosterone with a PDE5 inhibitor in some men who have both ED and low testosterone.
Next step: If ED is persistent, arrange an evaluation that includes repeat early-morning testosterone testing and an assessment of vascular, metabolic, medication-related, and psychological causes.