Men who have a problem with their sexual performance may be reluctant to talk to their doctor about an embarrassing issue. But modern medicine understands that there are numerous medical and psychological explanations for erectile dysfunction, including the possibility of underlying conditions that are important to address.

The problem could also be one with a solution – and doctors are used to dealing with embarrassing issues in private consultations. If you or someone close to you has a problem with erections, this article offers helpful information.

What is erectile dysfunction?

A man has erectile dysfunction when his penis has regularly failed to give an erection that has been good enough to achieve or maintain sexual penetration.^1-3

Most men have occasionally experienced some difficulty with their penis becoming hard or staying firm, but this is not erectile dysfunction, which is a concern only if satisfactory sexual performance has been impossible on a persistent number of occasions for some time.

Broadly, two forms of erectile dysfunction can affect men’s sex lives – the main cause is either medical or psychosocial.

Here, psychosocial means psychological effects – including the effects of social relationships – on sexual performance. Of course, medical conditions can also affect psychological wellbeing, and while the main cause of sexual impotence will be medical or psychological, there can be overlap between the two.

Erectile dysfunction used to be known more widely as ‘impotence’ before the causes became better understood and successful treatments came into use. Impotence is a term that is still in use, however.

What causes erectile dysfunction?

In this section:

• Blood vessel (vascular) causes
• Full list of biological causes
• Some of the prescription drugs that can cause ED
• Psychological causes
• Does riding a bicycle cause erectile dysfunction?
• Prostate disease and erectile dysfunction

To understand the causes of erectile dysfunction, it helps to understand how an erection happens physically.

Relaxation of muscle (in parts of the penis and the walls of the arteries supplying it) allows blood to rush into the cylinder-shaped spongy tissue of the so-called erection chambers, and valves prevent the venous loss of this pressure. The resulting hardness persists until after stimulation has stopped or an ejaculation has happened.⁴

This blood flow process is led by nervous and hormonal triggers activated when the brain is stimulated by touch or other stimuli, and these brain signals can be suppressed by anxiety.⁴

Effects against any of the following normal physiological contributions needed for an erect penis could affect normal erectile function:¹

• Blood flow
• Nervous supply
• Hormones.

Vascular causes that affect blood flow, and neurological causes that affect nerve signals are the major medical causes of erectile dysfunction, often due to the underlying disease processes of atherosclerosis and diabetes.⁵

Smoking and diabetes often cause atherosclerosis, and this narrowing or ‘clogging’ of arteries in the penis is the most common vascular cause of erectile dysfunction.⁵

Diabetes can also lead to neuropathy – damage to the nerves. Diabetic neuropathy is a common neurological cause of erectile dysfunction, as is nerve damage resulting from various types of surgery around the pelvis. Less common neurological causes are stroke, a type of epilepsy (partial complex seizures), multiple sclerosis, non-diabetic neuropathy, and spinal cord injury.⁵

Reducing well-established risk factors for diabetes and atherosclerosis – including diet, physical activity and other lifestyle factors such as smoking – could also prevent erectile dysfunction.

More about the vascular causes of erectile dysfunction

Atherosclerosis – the thickening of the walls of the arteries that causes them to narrow, restricting blood flow – can cause erectile dysfunction.

The earliest changes caused by atherosclerosis – damage to the lining of the arteries (medically known as endothelial dysfunction) – affect the penis first.⁶

While the downside to this is that the ability to get an erection is affected, the upside is that erectile dysfunction can be an early sign of artery disease, meaning that treatment and prevention of both heart problems and the sexual dysfunction itself can be sought early.

The early damage of atherosclerosis prevents the arteries to the penis from dilating (widening) properly, in turn preventing the penis from filling with blood and so becoming hard.⁶

Another cardiovascular risk factor, hypertension, can also cause erectile dysfunction.

The American Heart Association explains that high blood pressure can lead to erectile dysfunction because it damages arteries throughout the vascular system, impairing the blood flow necessary for achieving and sustaining an erection.⁷

Full list of physical causes

Because an individual cause of erectile dysfunction could be any one of those listed here – and many are not – persistent erection problems are always worth talking to a doctor about. Whether the cause is simple or serious, a proper diagnosis will help to address any underlying medical issues as well as helping to solve the sex problem.

The following list summarizes many of the most common physical/organic causes of erectile dysfunction:^1,5,8

• Heart disease and narrowing of blood vessels
• Diabetes
• High blood pressure(These first three are discussed above)
• High cholesterol
• Obesity and metabolic syndrome (which are also risk factors for diabetes)
• Parkinson’s disease
• Multiple sclerosis
• Hormonal disorders including thyroid conditions and testosterone deficiency (hypogonadism)
• Structural/anatomical disorder of the penis, such as Peyronie disease
• Smoking, alcoholism and substance abuse, including cocaine use
• Treatments for prostate disease
• Surgical complications (surgeries include radical prostatectomy, cystectomy, transurethral resection of the prostate and rectal cancer surgery)
• Injuries in the pelvic area or spinal cord
• Radiation therapy to the pelvic region.

Numerous prescription medications are also an organic cause of erectile dysfunction, including the below.⁵ Of course, people seeking to stop or change medication should always talk to a doctor or pharmacy professional first.

• Drugs to control high blood pressure (antihypertensives such as beta-blockers and clonidine)
• Heart medications such as digoxin
• Some diuretics (known as ‘water pills’ that increase urine output)
• Drugs that act on the central nervous system (on the brain or spinal cord), including some sleeping pills and amphetamines
• Anxiety treatments (anxiolytics)
• Antidepressants, including monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), and tricyclic antidepressants
• Opioid painkillers
• Some cancer drugs, including chemotherapy
• Prostate treatments, including treatments for cancer, and for benign disease (5α-reductase inhibitors). Anti-androgen drugs are also a cause, used in other conditions as well as prostate disease
• Anticholinergics – drugs with a wide range of uses that block a neurotransmitter (nerve signal molecule)
• Hormone drugs, including estrogens and drugs that act on luteinizing hormone-releasing hormone
• The peptic ulcer medication cimetidine

The organic causes account for as much as 90% of true (persistent) cases of erectile dysfunction – psychological causes are much less common.⁵

Psychological causes of erectile dysfunction

In the rare cases of erectile dysfunction having always been present (what doctors call ‘primary’ ED – when a man has never been able to have an erection), the cause is almost always psychological if it has not been caused by an obvious anatomical deformity:⁵

• Guilt
• Fear of intimacy
• Depression
• Severe anxiety.

Most cases of erectile dysfunction, however, are ‘secondary’ – the man has had normal erectile function before, but now has problems. Causes of a new and persistent problem are usually physical, but in the less common cases of a psychological cause, the below are examples, and each can cause or worsen erectile dysfunction.

Ranging from treatable mental health illnesses, to everyday effects that most people experience at some time, many of the following psychological causes can also cause temporary erection problems that would not be classed as erectile dysfunction.

Psychogenic factors preventing an erection can sometimes be related to a particular place, time, or partner.⁵

The psychological causes include:^1,4,5,8,9

• Depression – which can cause a loss of interest in sex (lower libido) as well as erectile dysfunction – and other mental health disorders
• Stress, fear, anxiety, or anger
• Stress can include work, financial, and emotional problems
• Performance anxiety – repeated feelings of doubt and failure in which worrying about getting an erection can cause a cycle of anxiety that prevents one from being possible
• Poor communication with a sex partner
• Other relationship problems such as pressure from a sex partner – for example, because expectations make sex a task instead of a pleasure.

Does riding a bicycle cause erectile dysfunction?

Questions about effects from riding a bicycle on men’s health – saddle effects – are still to be fully answered.

There have been concerns that regularly cycling for long hours could be linked to a higher likelihood of erectile dysfunction, and other men’s health issues of infertility and prostate cancer.

The most recent study to investigate this found that there was no link between riding a bike and erectile dysfunction, but it did find an association between longer hours of cycling and the risk of prostate cancer.¹⁰

However, the lead author has said men should not worry about the research because there is an overall benefit from riding that outweighs concerns, which have been raised but not proven:¹¹

Guidelines followed by doctors in the UK offer a practical suggestion – that men cycling more than three hours a week who are concerned that this may be resulting in erection problems could simply stop the activity for a period, and look for any improvement as a result.³

They add that if it is not possible to stop cycling, preventive measures could be tried, such as the use of a “properly fitted bicycle seat” ridden in a “suitable position.”³

Prostate disease and erectile dysfunction

Treatment of prostate cancer can cause erectile dysfunction, although the cancer itself does not cause the problem.

Prostate surgery to remove cancer – even when nerves are spared and procedures are done by the finest surgeons – can result in erectile dysfunction, as can radiation therapy to treat prostate cancer.¹²

This is because of trauma to the delicate nerves and blood vessels that are necessary for erections – but for many men, the ability to have erections returns within the first few months after treatment.¹²

Treatment of non-cancerous, benign prostate disease can cause ED. Drugs called 5α-reductase inhibitors are used to treat benign prostatic hyperplasia – prostate enlargement – and they can cause erectile dysfunction.⁵