The causes of impotence

A subject that causes much psychological distress it’s important to understand that impotence is a bodily dysfunction, just like any other. For the human body to work perfectly, a complex chain of connections need to work smoothly, like the wheels in a cog, and it takes just one link to falter for the whole process to stop working as it should.

In many cases, impotence is not because the penis isn’t working, but other parts of the body, which in turn prevent the necessary blood flow. For some men, the cause may be attributed to more than one reason, another complicating factor.

Before looking at the reasons why impotence can occur, it’s worth first taking some time to understand how an erection occurs in the first place.

The circulatory system of the human body

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The biological process

When a man starts to feel sexually aroused, the nerves in the penis receive a message from the brain which allows blood flow to increase by widening the penile arteries. As a result of this increased blood flow, the tissues in the penis start to expand and harden, creating an erection.

As the inner part of the penis becomes engorged and swollen, the veins which normally allow blood to flow back out and into the body becomes compressed. This vastly reduces the amount of blood which drains away, improving the quality of the erection even further.

Any problem with the relaying of the message between the brain and the nerves in the penis means that blood flow won’t be increased. Equally, restrictions in blood flow will also prevent the penis from getting the extra it needs it order to be able to generate and sustain an erection.

And of course, there may be psychological factors which influence a man’s libido; and if the desire is somewhat dampened, the message to the brain may not be sufficiently strong to trigger the biological reaction required.

Therefore, in order for an erection to occur, there needs to be collaboration between the libido, the brain, the hormones, the circulatory system and the nervous system. If there’s any slight problem in any of these bodily systems, erections can be difficult to either generate or maintain.

It’s estimated that around 80-90% of cases of impotence have a physical cause.

Vascular conditions

By far the most common cause of all the physical problems which lead to impotence, around 73% of cases are thought to be due to vascular conditions and diabetes.

Any disease relating to the heart or blood vessels is classified as a vascular condition; this includes high blood pressure, heart disease and narrowing of the arteries.

Just like all the other arteries in the body, those leading to the penis can be affected by hardening and narrowing – known as atherosclerosis – and this in turn can reduce the amount of blood which reaches the penis.

Diabetes has a similar effect. When there’s too much sugar in the blood, as with diabetes, the efficient flow of blood around the body can be affected, once again making sustaining an erection difficult. Diabetes also has some neurogenic (see below) effects as it also prevents the nerve endings in the penis from doing what they should.

Testing blood sugar with Diabetes strips is a useful general health idea

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Smoking or being overweight will exacerbate these problems significantly.

Neurological conditions

Any disturbance in the brain or its functioning has the potential to impact significantly on the ability to get or sustain an erection.

In around 10% of cases where there is a physical cause, there is a neurological explanation for the problem.

Neurological disorders can arise from an accident or injury, such as when the spinal cord is damaged, of they can result from an illness, condition or disease. Parkinson’s disease, multiple sclerosis or suffering a stroke can all lead to a neurological deficit significant enough to interfere with the ability to sustain an erection.

In many cases, the stroke may be caused by the same process as cardiovascular disease, the only difference is that its arteries in the brain which are affected, narrowing and hardening.

Hormonal problems

The body is a finely balanced machine and it only takes one system to be slightly out of kilter in order for things to stop working, the penis included.

Hormone problems are estimated to be at the root of around 11% of cases with a physical cause.

Cushing’s syndrome is a condition which interferes with the production of cortisol, a hormone whilst hypogonadism reduced production of the male hormone testosterone, resulting in significantly lower levels.

Other hormone conditions which can also play a role include both overactive and under active thyroid glands, known as hyperthyroidism and hypothyroidism.

Other physical causes

Vascular, neurological or hormonal problems are the most common physical causes of impotence but there are many others which can also contribute.

Pelvic surgery or trauma, such as that sustained after an accident can trigger erectile dysfunction, estimated to be the cause in around 3-5% of cases.

A more direct cause such as an anatomical abnormality with the penis itself may also cause impotence, although this doesn’t necessarily have to be the case. Some of the conditions which may result in impotence include Peyronie’s disease, other types of penile curvature, a tight foreskin, shortened frenulum and inflammation.

Anatomical abnormalities are actually less common than other causes of impotence, estimated to be responsible for around 1-3% of cases.

Drugs and medication

It’s not always an underlying physical condition which is at the root of impotence; in some cases the treatment for an unrelated condition may have unwanted side effects, including erectile problems.

This can represent a real dilemma, especially if the original complaint didn’t result in any difficulty sustaining an erection. On these occasions, it’s always worth discussing alternative medication with your doctor before considering getting treatment for impotence.

The side effects of medication can vary very significantly between individuals, and factors such as the dosage and interactions with other drugs can help to determine whether or not undesirable reactions will occur. But even in two individuals who are taking the same drugs at the same dose, the outcome can be different.

Below is a list of the types of drugs which are known for being particularly likely to cause impotence in some cases. However, it is essential that medication is not stopped suddenly and that any changes are discussed with a doctor first.

Here are some of the groups of medications which could cause impotence in some men:

Anti-androgens: used to lower male sex hormones naturally produced by the body

Anticonvulsants: used to prevent fits and seizures

Antidepressants: used to treat both anxiety and depression, as well as some types of pain disorder

Antihistamines: used to treat allergic reactions and conditions including hay fever

Antihypertensives: used to lower blood pressure in order to try and prevent the effects of cardiovascular disease

Antipsychotics: used to treat certain types of mental health conditions including schizophrenia

Beta blockers: officially a type of anti-hypertensive drug, they can also be prescribed for anxiety and other conditions

Corticosteroids: not to be mixed up with anabolic steroids, corticosteroids are a type of hormone steroid often used to reduce inflammation

Cytotoxics: used to reduce the amount of cell growth and division in cancer as part of a chemotherapy regime

Diuretics: used to increase the amount of water and sodium removed from the body by upping urine production

Fibrates: the collective description for drugs which lower the bad cholesterol

H2 antagonists: used to relieve stomach ulcers

Miscellaneous reasons

Even if there’s no obvious physical cause or medication triggering impotence, the cause can sometimes be identified by looking at an individual’s lifestyle.

A collection of poor lifestyle habits, although they may seem relatively trivial, can add up to create problems resulting in impotence.

Smoking, excessive drinking, being overweight, stress, a lack of exercise, poorly controlled diabetes and use of recreational drugs can all cause impotence.


As well as increasing the likelihood of developing narrowing and hardening of the arteries, a condition which will automatically enhance the risk of impotence, smoking reduces the circulation of blood.

This reduced blood flow can damage the ability to sustain an erection and in some cases simply stopping smoking can be enough to resolve the problem.

Excessive drinking

Defined as more than two drinks per day, excessive alcohol will restrict the blood flow to the penis. It can also impair the production of testosterone, inhibiting the libido. Both of these factors can create substantial problems with sustaining an erection.

Excessive drinking is a real problem with impotence

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Research has shown that being overweight raises the risk of developing impotence. It also increases the chance of developing vascular disease, further diminishing the ability to get an erection.


Overlapping with psychological factors, stress can mean it’s difficult to switch off and relax, thus making it hard to feel aroused enough to trigger the process. Stress can cause impotence and simply reducing this can restore erectile performance.

Lack of exercise

As well as helping to reduce the risk of vascular disease, taking regular exercise has been shown to actively reduce the likelihood of impotence.

Poorly controlled diabetes

If diabetes is not well controlled it can result in complications which could include impotence. This is due to a reduced blood flow which stops the nerve endings in the penis from working as they should. Taking the right level of medication, getting regular exercise, sticking to a healthy diet and monitoring blood glucose levels are all key to controlling diabetes.

Recreational drugs

Marijuana, cocaine and ecstasy, as well as other recreational drugs, all have the potential to cause impotence, which in some cases can be irreversible due to damage caused to the blood vessels.

Psychological factors

When examining impotence and the possible causes, it’s important to first rule out any underlying cause such as a physical condition, or the likelihood of a medication preventing an erection from occurring.

A good look at the individual’s general health and lifestyle is also required, as the cause can simply be an accumulation of minor problems.

But if no cause can be found, it may be that the reason for impotence is due to psychological factors.

It’s important to stress that being triggered by psychological distress makes the condition no less severe, nor any less significant. An individual can’t simply ‘pull themselves together’ if psychological problems are leading to erectile difficulties.

Psychological factors can lead to a reduction in the hormones being produced, which in turn diminishes the message that the brain sends to the penis. Although the initial cause may be psychological, the effect is physical.

There are a range of psychological issues which could impact on the ability to sustain an erection, and the extent to which sexual function is affected varies from person to person. It should never be seen as a reflection on how much a man likes their sexual partner as the process is far more fundamental than that.

Some of the issues which can result in impotence include a history of sexual abuse, anxiety, depression, a new relationship, relationship difficulties or a lack of experience.

In many cases, it may be a combination of both physical and psychological factors which cause impotence, a cycle which can be tricky to break.

For example, if you have high blood pressure and on beta blocker medication, you may find at times that it’s difficult to sustain an erection. In turn, you then become anxious about sex and whether you’ll be able to adequately perform.

Finding the cause

In many cases the cause may be attributed to more than one factor, and taking time to relax, cutting out unhealthy habits and improving diet and exercise can be all that’s needed in order to restore full erectile function.

Unhealthy eating habits

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However, when the problems are more deep-rooted, or there’s a physical cause which can’t be immediately resolved, treatment may be necessary. There are a range of difference treatments that can be offered and these are very effective in overcoming impotence. However, a doctor will always want to establish the root cause of the problem first rather than simply hand out medication.

Image Credits: Wikipedia, Bodytel, Antoine de Morris and Skippy Jon