What Is Erectile Dysfunction?

Simply, ED is when the penis is unable to become sufficiently erect for sexual intercourse to occur. There are many possible root causes but it is lack of blood flow to the penis which is the main issue that creates ED.


Erectile dysfunction (ED) is more relevant than you think. Some estimates suggest up to 41.5% of men have ED issues in the UK.1 A blood issue? Hormones? Diabetes? There are many possible causes for this complex issue and many possible solutions.

Occasional erection problems are probably nothing to be concerned about but recurring issues can be a sign of deeper underlying issues. This is a sensitive topic for many but it does not need to be this way. Just as some people need assistance with their eyesight and some need assistance with their blood sugar, some people will need assistance for ED. Ultimately, just like any other form of bodily dysfunction, this is a real issue with real causes and real solutions.

Though your doctor is more able to directly target specific issues with ED, this article is here to help you understand why this issue can arise, what the treatment options are, and ultimately, what ED is.

Causes & risk factors of erectile dysfunction

The direct cause of ED is lack of sufficient blood flow to the blood vessels in and around the penis. This issue is linked to many other issues such as:

  • Prostate cancer treatment
  • Decreased testosterone levels
  • High blood pressure
  • Diabetes
  • Smoking and poor lifestyle choices
  • Depression
  • Medication

Prostate cancer

Prostate surgery to remove prostate cancer can be a key life-saving surgery. However, side effects can include ED with between 24% and 87% of prostate cancer-treated patients affected (treatment type dependent).2 This can be due to hormonal therapy which decreases testosterone levels, or due to mechanical damage of nerves during surgery.3 Hormonal changes may be reversed in recovery from treatment, whilst nerve damage is normally permanent.


Testosterone plays a key role in male sexual function and thus ED.4 Declining testosterone levels are a common part of the ageing process with classic studies indicating a 2-3% decrease in available testosterone per year after 40.5 This is due to decreased testicular function alongside decreased function of the pituitary (the part of the brain which controls signals for the production of testosterone among other hormones) in a combination process known as hypogonadism.6 The complexity of this process is not fully understood but a recent theory suggests that excess fat and the hormone it produces (leptin) around the testicular area can contribute to suppressed testosterone production - though this might not explain the brain-related links.7 A more commonly held belief is that this issue is caused by stiffening, and thus decreased function, of the micro-blood vessels that feed the testosterone-producing Leydig cells.6

Blood pressure

Decreased blood vessel function is the more direct mechanism by which high blood pressure can affect ED.8 High blood pressure creates a snowball-like effect in which blood vessels are damaged by excess stress of increased blood flow and pressure, with the damaged blood vessels causing higher blood pressure due to decreased ability to stretch. The initial cause to kick off this cascade can be diets with excess fat, smoking, excess salt intake, or even just ageing. Ultimately, this lack of healthy blood vessels directly causes ED with approximately two times as many high blood pressure patients affected.7 


For diabetes patients, patients are over three times more likely to develop ED symptoms than non-sufferers.9 The relationship between diabetes and ED is very complicated with many factors that cause ED also causing diabetes.10 More directly, the common feature of poorly regulated diabetes (high blood sugar) is known to create a cascade of events by creating an inflammatory environment. In this environment, immune cells go into overdrive, reactive and destructive molecules (known as reactive oxygen species) are released, the production of nitrous oxide (a blood flow promoting agent) is downregulated, blood vessels narrow and retract maximally (the process of vasoconstriction), and blood flow to the penis is reduced; culminating in ED.11 Additionally, this process can also produce significant irreversible nerve damage. This is the same process that can also lead to limb function being massively impaired, and eventually amputated, in diabetes patients.12 


Smoking is one of many poor lifestyle choices that can exacerbate ED issues, as men who smoke are found to be 51% more likely to develop ED.13 The decreased blood vessel health associated with smoking is likely behind this. This same reasoning also applies to those who have poor cardiovascular health due to lack of exercise.14  Whilst alcohol consumption also seems to be a cause of ED, the mechanism of this seems to be broader, with brain wastage, increased inflammation, and the depressive nature of alcohol all thought to play a role.15,16


It is important to note that psychological factors can also play a role in erection problems.

The negative depressive effects of alcohol also apply to depression as a mental illness.17 Declining mental health due to other factors can cause a malfunction in the pituitary gland (the key part of the brain for stimulating testosterone production) which in turn can create testosterone dysfunction and ED. This is another issue with a negative feedback loop - meaning that the negative effects in brain chemistry cause ED which negatively affects brain chemistry and worsens ED. 

Problematically, some anti-depression medications have also been found to cause ED.18 Both selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) have been found to cause an increase in sexual dysfunction prevalence with some estimates showing almost 60% of antidepressant patients will experience this.19 

These common forms of antidepressants function by manipulating the hormones norepinephrine and/or serotonin in an attempt to sensitise the brain to their actions. Whilst these hormones play a key role in arousal and other elements of sexual function, serotonin is also linked to decreased production of nitric oxide, an aforementioned promoter of increased blood flow.20 As such, oral medications that moderate excessive good-mood hormone also moderate blood flow to the penis and the ability to maintain healthy penile erection. 

Signs and symptoms of erectile dysfunction

According to the NHS, ED has two key elements:

  • Inability to get an erection
  • Inability to maintain an erection sufficient for sexual intercourse to take place21

It’s important to note that occasional erections are not enough to completely negate a diagnosis of ED if one of the above points also applies.

Management and treatment for erectile dysfunction

Some men won’t have to do anything with ED - it may not be a problem in their life and this is fine. ED is not a life-threatening disease.

However, quality of life can still be significantly affected and some patients may want to boost their blood flow with the help of ED medication and treatment. 

For some, it may be most appropriate to take action with the underlying issue: stopping smoking, exercising more, and appropriately managing diabetes. Similarly, supplementary testosterone replacement therapy is an option for those attempting to reverse the underlying issue of low testosterone levels.22

That being said, there are also more direct treatment options. Some issues may be unable to be reversed: irreversible nerve damage and antidepressant management may not be simple. 

Whether you are not able to address bigger issues, or whether you just don’t want to, there are treatment options proven to directly increase blood flow to the penis and provide an immediate benefit.

Since the first approval in 1998, there are oral medications (now totalling four) for ED.23,24 Sildenafil, tadalafil, vardenafil, and avanafil all  function by signalling for blood vessels to be opened, allowing increased blood flow to the penis. Some treatments may require a prescription whilst others are available over the counter.

Though instructions for use and long-term management differ, all of these treatments have proven to provide significant benefits for ED with the approximate 34% improvement from sildenafil treatment similarly achieved with other PDE5 oral medications.24 

Though oral medications are the most common, other direct immediately beneficial treatments exist.The most common alternative therapy is an external pumping device known as a vacuum constriction device. The pump is fitted on the penis and secured in place at the base to create an airtight seal, before pumping out air, creating negative air pressure and drawing blood to the penis. Whilst the theory is solid, as an external non-surgical treatment option, vacuum constriction devices have not had to go through clinical trials so studies on their effectiveness vary greatly between 35-85%.25

Additional less common treatments include inflatable implants, medicines inserted into the tip of the penis, and injections into the penis. Though these can offer some benefits, the risks and uncomfortable complications that may be associated with these treatments mean that these are typically only chosen after the failure of other treatments.

Diagnosis of erectile dysfunction

Whilst there are methods to objectively analyse ED such as ultrasounds to evaluate blood flow, ED is typically diagnosed by your healthcare professional examining medical history and asking a series of questions on sexual health and habits.26

Though ED itself is not a disease, it can also be an indication of bigger issues. As such, healthcare professionals may also run blood tests and check for underlying conditions.


Though treatment of ED is able to produce significant improvement, it is not without potential complications.

  • Hypotension (low blood pressure) can be worsened by ED medication
    • Heart conditions should be considered before using this medication
    • PDE5 inhibitors combined with medicines containing nitrates can excessively widen blood vessels
  • Effectiveness of immediate treatments used pre-sexual intercourse can be limited by the unnatural-ness of the scenario
  • Severity of underlying condition may significantly reduce the effectiveness of treatment
    • Nerve damage due to diabetes
    • Chronic heart disease
  • Treatment of underlying issues often has its own side effects

Due to potential complications and to create realistic expectations, it is advised to consult with a healthcare professional before utilising any treatments.


How can I prevent erectile dysfunction

Exercise regularly, do not smoke, and manage blood sugar. Make healthy lifestyle choices!

How common is erectile dysfunction

Studies of ED commonness vary but could be as high as 41.5% of UK males.1 

When should I see a doctor

If you are regularly unable to produce and maintain an erection sufficient for sexual intercourse to take place.


Erectile dysfunction is a common ailment amongst individuals male at birth. It can be a sign of more major underlying conditions such as heart failure, high blood pressure, or diabetes. There are treatment options available to produce significant improvements with varying degrees of effectiveness. Ultimately, though this issue will not directly cause loss of life, it is something which can limit the quality of life and may indirectly create or be a symptom of other issues, so a healthcare professional should always help decide what is right for you.


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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Maxwell Dobney

Masters of Biology – Mbiol, Aston University, England

Maxwell is a first-class honours biology graduate with good understanding of tone and reliable accuracy from employment experience in the realm of technical writing and bid writing.

He is now producing informative, insightful, and impactful content to lower the barrier of entry to complex science whilst gaining experience in the MedComms world.

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