What Causes Erectile Dysfunction? 8 Common Reasons

Updated in December 2023

Erectile dysfunction is usually associated with excessive use of certain medications, depression, tobacco use, alcoholism, trauma, decreased libido or hormonal diseases. This condition interferes with pleasurable sex in men, which can lead to many mental roadblocks for both partners.

Erectile dysfunction is described as the difficulty or inability to maintain an erection in at least 50% of attempts at sexual contact. In some cases, the erection may not be sufficiently stiff to achieve penetration. 

Men are advised to consult their family doctor or a urologist if they have difficulty maintaining or triggering an erection, and if they are unable to engage in satisfactory sexual activity. Treatment may include medications, psychotherapy or other exercises. 

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Common causes

The most common causes of erectile dysfunction (ED) include:

1. Prolonged use of certain medications

Some medications that are used to treat chronic problems (like blood pressure or depression) can lead to erectile dysfunction as a side effect of long term use. Prolonged use of antidepressants, antihypertensives or antipsychotics are commonly seen in cases of ED.  

Therefore, if you have been using medication for a long time and start experiencing erectile dysfunction, you should follow-up with your prescriber.

2. Excessive intake of alcohol or tobacco 

In addition to negatively affecting your overall health, alcohol or tobacco dependency can also affect normal genital functioning. These substances can impede circulation and reduce the blood flow needed to maintain an erection. 

Men who smoke or drink excessively for many years may have more difficulty achieving an erection, leading to erectile dysfunction. 

3. Hormonal diseases

Problems related to abnormal hormone level, like hypothyroidism or diabetes, may affect overall metabolism as well as normal sexual functioning. This can contribute to erectile dysfunction. 

There are also conditions associated with reduced sex hormone production (like low testosterone levels), which can decrease libido and lead to more difficulty maintaining an erection. 

4. Depression or other psychological disorders 

Psychological disorders, like depression or anxiety disorders, can trigger negative feelings like fear, anxiety, nervousness and dissatisfaction, which can make men less comfortable during moments of sex. This can negatively impact the ability to achieve and maintain an erection. 

5. Drug use

Most drugs, like alcohol and cigarettes, can cause ED over time, not only due to decreased blood flow to the penis, but also due to psychological changes that can displace the mind from the real world. 

Drugs that are more frequently associated with erectile dysfunction include cocaine, marijuana or heroin.

6. Excess weight or obesity 

Excess weight can contribute to erectile dysfunction in two ways. First, being overweight can increase the risk for cardiovascular disease, like atherosclerosis, which makes normal blood circulation in the body (and to the penis) more difficult. Second, obesity may reduce testosterone production, which is the main hormone responsible for libido in men. 

Weight loss and regular exercise are a great way to address ED in patients who are overweight. Check out our online calculator to determine your ideal weight, according to height and age.

7. Penile changes 

Although it is more rare, erectile dysfunction can also occur as a result of penile deformities, like fibrosis, cysts or anatomical abnormalities that interfere with normal blood flow. 

Therefore, if there is no other underlying cause for ED, you should consult a urologist for a penis anatomy assessment.

8. Neurological diseases 

There are many neurological diseases that are associated with a higher risk for erectile dysfunction, as many nerve-related problems can interfere with normal communication between the brain and the penis. 

Some conditions associated with ED include Alzheimer’s disease, Parkinson’s, brain tumors and multiple sclerosis. 

When to see a doctor 

If you have symptoms like difficulty achieving or maintaining an erection, a flaccid erection, decreased penis size or difficulty having sex in specific conditions, you should see a doctor for assessment. The doctor will assess your symptoms to identify the underlying cause and recommended treatment as appropriate. 

ED can be treated in many ways, depending on the underlying cause. The doctor may prescribe medications (like sildenafil or tadalafil), hormonal replacement therapy, suction equipment or surgical interventions.