What is erectile dysfunction?
Erectile dysfunction, otherwise known as ED or impotence, is the condition of being unable to get or maintain an erection.
It is a common condition that most males will experience at some stage in their life, though it is most prevalent in older men. ED is usually temporary rather than permanent, although it can also be recurring, depending on whether the cause is short-term and treatable, or ongoing.
The possible causes of ED are numerous. Physical causes of ED include aging, high blood pressure, conditions which affect the blood vessels and/or nerves associated with the penis, and nerve damage to the area which occurs due to injuries, or certain surgeries such as prostate surgery. Psychological causes of ED include depression, anxiety and relationship issues.
In most cases, erectile dysfunction can be successfully managed, with treatment options depending on the root cause of the disorder. Treatment may involve forms of sex therapy and counseling, exercises and lifestyle changes, ED drugs, including pills and topical medications, pumps and ‒ in more severe cases ‒ prosthetics.
Symptoms of erectile dysfunction
The symptoms of erectile dysfunction may include:
- An inability to get an erection
- An inability to maintain an erection during sexual activity
These symptoms may come and go over time or be situational, for example not present during masturbation but present with a partner. If symptoms occur regularly or semi-regularly, visiting a doctor is advised.
The onset of ED may be different, depending on whether it is caused by physical or psychological factors:
If the causes of erectile dysfunction are physical in origin, the condition is more likely to appear gradually, with the problem occurring intermittently before becoming more frequent. A person’s sex drive is unlikely to be affected, unless the root cause is hormonal in nature.
Psychological causes typically result in the sudden onset of the condition. If a person is able to get and maintain a healthy erection sometimes, for example when masturbating or on waking, it may be a sign that their erectile dysfunction is psychological in origin. If you are affected by unexplained ED, you can get a free symptom assessment at any time by downloading the Ada app.
Causes of erectile dysfunction
Finding a treatment approach that can cure erectile dysfunction usually depends on identifying its root cause.
Erectile dysfunction can be caused by a variety of physical and psychological factors:
Physical causes of ED
Most cases of erectile dysfunction are caused by physical factors. The most common cause for erectile dysfunction is reduced blood flow to the penis. This happens as a result of a narrowing of the arteries in the penis.
Conditions which can lead to the development of erectile dysfunction include:
- Diabetes, which can affect the function of the blood vessels and nerves
- Parkinson’s disease, either as a side-effect of medication or due to the condition itself
- Multiple sclerosis, a condition associated with progressive damage of the nerves, including those associated with getting and maintaining erections
Other factors which are recognised as physical causes of erectile dysfunction include:
- Excessive intake of alcohol or drugs, which can impair the ability to get or maintain an erection.
- Medications which cause ED as a side-effect, such as certain kinds of antidepressants, beta blockers and some diuretics
- A lack of certain hormones, particularly testosterone. (ED caused by hormone deficiencies is uncommon.)
- Damage to the nerves in the penis as a result of surgery to nearby areas, such as prostate surgery, or from an injury, such as a spinal cord injury
Erectile dysfunction after prostatectomy (prostate surgery)
All prostate surgery procedures disrupt the nerves and blood vessels that control the way erections form. For this reason, all prostatectomies will compromise erectile function, at least initially.
Up to 50 percent of men who have had a successful nerve-sparing procedure, i.e. the nerves were left untouched as planned during the procedure, regain their pre-prostatectomy erectile functionality during recovery, within one year.
For men who have not had nerve-sparing procedures, it is usually still possible to recover most or the entire extent of their pre-treatment erectile capability. In cases where spontaneous erections are no longer possible, there are several possible treatment options which may help with overcoming erectile dysfunction after a prostatectomy. These include:
All of these medications work by increasing blood flow to the penis, causing an erection. (For more information about remedies for ED after having a prostatectomy, see treatment.)
Psychological causes of ED
A range of mental health issues can lead to the development of erectile dysfunction, including:
- Relationship issues
Purely psychological causes for erectile dysfunction are less common, limited to approximately 10 percent of cases.
Genetics and ED
It is suspected that there is a hereditary component to ED in around one third of cases. A 2018 study has proven the link for the first time, finding that certain variations in some people’s genetic structure increase their risk of developing erectile dysfunction.
This discovery paves the way for the development of new treatments to help relieve ED in cases where its cause may be genetic.
Risk factors for developing erectile dysfunction
Risk factors for erectile dysfunction include:
- Aging ‒ the older a person is, the greater the risk of developing ED
- High blood pressure
- High cholesterol
- The use of tobacco products
- Injuries to the groin or surgery, such as prostatectomy, which affects the nerves responsible for erections
Risk factors for ED after a prostatectomy – surgical removal of part or all of the prostate
Following a prostatectomy, the risk of erectile dysfunction is influenced by factors including:
- The skill of the urologist or urological surgeon. The greater their surgical experience and success rate at preserving sexual function, the more likely a given procedure is to conclude with this outcome.
- Age of the patient. Younger men are more likely than older men to keep or regain their erectile abilities.
- Previous sexual profile. The greater a man’s ability to produce erections before the procedure, the more likely he is to keep or regain it after the procedure.
If both bundles of nerves responsible for erections are sufficiently damaged, it may no longer be possible for a man to have spontaneous erections without the aid of devices or medications that assist the bodily process. (For more information about remedies for ED after having a prostatectomy, see treatment.)
Diagnosis of erectile dysfunction
The first step in treating ED is getting a diagnosis of the root cause by visiting a doctor, who will typically begin with questions regarding:
- The symptoms experienced
- The length of time symptoms have been present
- General physical and mental health
- Levels of alcohol and drug intake
- Whether any other medication is also being taken
It may also be necessary for a person to answer questions about their sex life. These may include:
- Details of current and past sexual relationships
- Information about sexual orientation
- Whether the dysfunction occurs all the time, intermittently or only in certain situations
- Whether ejaculation is possible
- Libido, i.e. levels of sexual desire
As narrowed blood vessels are the most common cause of erectile dysfunction, a doctor will usually examine a person’s cardiovascular condition as part of the diagnosis. This may involve testing for high blood pressure, checking for heart irregularities, as well as evaluating their weight or overall level of health.
Blood tests may also be ordered to check for underlying medical conditions that may be causing the condition.
Treatment for erectile dysfunction
In most cases, doctors will be able to suggest and prescribe treatment options. A person may also be referred to a specialist. Treatment methods will depend on the underlying cause of the problem, meaning the chosen method will differ from case to case.
Common treatment options for erectile dysfunction include:
Treatment of underlying conditions
If an underlying condition is causing erectile dysfunction, treating it will generally be the first step towards resolving erectile dysfunction.
If medications used to treat other conditions are thought to be causing erectile dysfunction, a doctor may be able to prescribe alternatives.
Good to know: Use of prescribed medication should never be discontinued without supervision by a doctor.
A range of lifestyle changes can help treat erectile dysfunction, including:
- Losing weight
- Reducing stress
- Quitting smoking
- Reducing alcohol and drug intake or giving them up completely
- Getting regular exercise
Exercises for ED
There are a number of exercises that may help to treat ED. These include:
- Pelvic floor exercises: Exercises designed to strengthen the pelvic floor muscles, such as Kegel exercises, can be effective in treating or preventing erectile dysfunction.
- Yoga: Can be effective in reducing stress and anxiety, psychological problems that can cause erectile dysfunction.
- Swimming: A good exercise for improving overall health, which can in turn help treat erectile dysfunction.
Counseling, sex therapy and relationship counseling
If stress, anxiety or depression are causing erectile dysfunction, counseling may be an effective treatment. If relationship issues are the cause, some form of sex therapy or relationship counseling may prove successful.
Sensate focus, a type of sex therapy, focuses on building intimacy between partners. It involves totally abstaining from sex and intimate touching for a set period of time, then gradually reintroducing it. The method can be effective in overcoming the psychological issues behind erectile dysfunction.
Relationship counseling, in which partners are prompted to explore the physical and psychological issues behind their sexual problems, may also be an effective method of overcoming erectile dysfunction. Partners are encouraged to become more aware of each other’s needs, allowing them to reach a solution which works for them both.
Oral medications for erectile dysfunction
Oral medications which are used to treat erectile dysfunction come in the form of tablets or pills. The drugs most commonly used to treat ED are called phosphodiesterase-5 (PDE-5) inhibitors.
Phosphodiesterase-5 (PDE-5) inhibitors
These medications work by counteracting phosphodiesterase-5 (PDE-5), a chemical naturally occurring in the body, thereby increasing blood flow to the penis during sexual stimulation.
PDE-5 inhibitors are the most commonly prescribed medication for treating erectile dysfunction. The most common types are:
- Sildenafil: Brand name, Viagra®
- Tadalafil: Brand name, Cialis
- Vardenafil: Brand name, Levitra
- Avanafil: Brand name, Spedra
These medications work by artificially dilating the blood vessels in the penis, enabling improved blood flow. The effects of tadalafil last for up to 36 hours, while the other three varieties generally last for around 10 hours. Each should be taken 30 to 60 minutes before engaging in sexual activity and will only take effect when one is sexually aroused.
A doctor will be able to advise about which type of PDE-5 is most suitable for each person and the health risks and side effects that come with them.
Good to know: Following a prostatectomy, if one, rather than both, sets of the nerve bundles responsible for erections has been damaged (a unilateral nerve-sparing prostatectomy), it is possible to use PDE-5 inhibitors to stimulate an erection.
PDE-5 inhibitors are associated with several side-effects including headaches, a runny nose, hot flushes, an upset stomach and light sensitivity. In some cases, they can cause more severe vision problems: a temporary or permanent blindness which may be a sign of non–arteritic anterior ischemic optic neuropathy (NAION). This eye condition has been linked to all brands of PDE-5 inhibitors. Recent research indicates that there is an approximate two-fold increase in the risk of NAION in men over 50 who have recently used PDE-5 inhibitors, compared to those who have not. However, the overall risk of PDE-5 inhibitors causing NAION is low, with a risk estimate of 2.27 percent in a 30 day period and 3.52 percent in a 12 month period. PDE-5 inhibitors are not recommended for people who have already been affected by NAION, or who have a family history of retinal degenerative disorders.
These medications are also known to react with nitrate-containing drugs used to treat heart disease, so it is important to discuss possible interactions with the doctor in cases where PDE-5 inhibitors may be taken in combination with other medications, especially heart medications.
An efficient medication for assisting erectile function is thought to be alprostadil, a man-made version of prostaglandin E1, a substance naturally made in the body to help produce erections. Generally, due to the fact that it is a relatively new treatment with limited safety data, alprostadil will only be prescribed if other treatments, including counseling, lifestyle changes and PDE-5 inhibitors, have been ineffective or are unsuitable. It is administered in three main forms:
- As an injection, directly into the base of the penis
- As a small pellet, which is placed into the urethra, i.e. the opening on the tip of the penis
- As a topical cream, applied to the urethra
Doctors will advise on which form of alprostadil should be used and give instructions on how to properly administer it at home. After application, an erection can usually be achieved in around 15 minutes.
Alprostadil side effects
Alprostadil has significantly fewer and less severe side effects than most oral medications which can be used to treat erectile dysfunction. It works by widening the blood vessels and increasing the blood flow to the penis, causing an erection.
If side effects occur, these are usually non-serious and are limited to prolonged erections, pain and dizziness. Another advantage of Alprostadil is that the dosage can be adjusted to determine the duration of an erection.
Topical medications for erectile dysfunction
A commonly prescribed topical medication for ED is Vitaros©, a prescription medicine in the form of a cream, containing the active ingredient alprostadil. This is the newest form of alprostadil.
Vitaros comes in a single-use container with a plunger, barrel and protective cap, containing either 200 or 300 micrograms of alprostadil in 100 mg of cream. The appropriate dose strength for each person is decided in consultation with their doctor.
Storage and application guidelines for Vitaros© include:
Vitaros should be stored in the fridge, but can be taken out before use in order to reach room temperature for ease of application. If it is taken directly out of the fridge, it may need to be warmed up for use by massaging the tube in one’s hands.
It is best to urinate before applying Vitaros. Urination after application will result in cream being expelled from the urethra, lessening its erectile effects.
Each tube of Vitaros contains the right amount of medication for a single dose, which should be applied, with clean hands by injecting it into the urethra, using the single-use applicator pump provided. The penis should then be kept upright for 30 seconds so that the cream can be absorbed. Any leftover cream can be rubbed in around the tip. Hands should be washed after application.
Vitaros will usually take effect in 5-30 minutes after application. It is not an aphrodisiac, and sexual stimulation will therefore be necessary to achieve an erection. For most people, the effects last between one and two hours. A full, warm sensation in the penis is not a cause for concern, and may remain for several hours after use.
Vitaros should not be used more than once within any 24-hour period. A person should not exceed three doses in a week.
Vacuum pumps can relieve the symptoms of erectile dysfunction. A specialized mechanical pump is used to cause an erection by placing it over the penis and sucking air out of the pump, drawing blood into the penis. Erections created with the use of a vacuum device require a band to be applied to the base of the penis to trap the blood for the duration of the intercouse. The band can then be removed afterwards.
For safety reasons, the rubber band should be removed within 30 minutes.
Penile prosthesis is a surgical procedure in which a rod is implanted inside the penis in order to simulate an erection. Advanced procedures involve the insertion of an inflatable rod. This is an uncommon treatment method for ED, used only in severe cases, but is generally effective.
Erectile dysfunction prevention
Though it may not always be possible to prevent erectile dysfunction, certain steps can be taken to reduce the risk of the condition. These include:
- Staying healthy, with regular exercise and a balanced diet, including meeting the recommended daily intake of all vitamins and minerals
- Stopping using tobacco products
- Avoiding drugs and excessive amounts of alcohol
- Seeking treatment for conditions such as high blood pressure and diabetes
Complications associated with erectile dysfunction
There are no serious physical complications associated with erectile dysfunction.However, the condition can negatively affect a person’s mental health, causing issues such as:
- Stress and anxiety
- Low self-esteem
- An unsatisfactory sex life
- Problems within a relationship
Erectile dysfunction FAQs
Q: What is the main cause of erectile dysfunction?
A: The root cause of erectile dysfunction is insufficient blood flow to the penis, which makes it difficult to get or maintain an erection. This can be due to a great variety of different physical and psychological reasons. The main causes of ED include:
- Conditions which affect the blood vessels and/or nerves responsible for erections, including Parkinson’s disease, multiple sclerosis and diabetes
- Excessive intake of alcohol or drugs
- Certain medications, that may cause impotence as a side effect
- Damage to the nerves responsible for erections from an injury or surgery
- Psychological factors, such as anxiety, depression or loss of libido
ED can be a sign of other, more serious conditions which affect the function of the nerves and blood vessels, including those listed above, so it is always important to identify the root cause if ED persists. If you or someone you know is affected, you can get a free symptom assessment at any time by downloading the Ada app.
Q: What can cause young people to be affected by erectile dysfunction?
A: Although ED is more likely to occur in people older than 50, it has become increasingly common in younger men, i.e. those aged 16 to 35. Unless it occurs due to a medical condition or structural damage to the nerves from surgery or injury, ED in young men is likely to be psychogenic, i.e. caused by psychological factors such as anxiety, depression and stress.
Common characteristics of young men with erectile dysfunction include:
- No history of conditions which typically may physically cause ED, such as diabetes, hypertension or pelvic injury
- A psychiatric diagnosis, for example, of depression, anxiety, post-traumatic stress disorder (PTSD) or bipolar disorder
- Difficulty sleeping or insomnia
- A demanding job
- Relationship or performance anxiety
- A high level of anxiety about the health implications of ED
- A fixation on finding a cure or a treatment with instant results
Treatment for young men affected by ED caused by psychological factors may involve taking medications such as PDE-5 inhibitors. However, any course of medication prescribed will usually be combined with psychotherapeutic interventions designed to identify and address the problems which are causing ED, for example by improving a person’s self-esteem or mediating their response to stress.
Q: Is there a permanent cure for erectile dysfunction?
A: Although there is no guaranteed cure for erectile dysfunction, there are a number of treatment options that can provide long-term relief. Treatment options affect everybody differently, meaning what proves effective for one person may not be the best option for another. Doctors can help advise on the best treatment methods.
Q: Are there any home remedies or natural products that can be used to prevent or treat erectile dysfunction?
A: Seeking medical advice before using any home remedy is advised. Many people report the use of home remedies to treat ED. However, natural products, including those listed below, are not recommended treatments for ED, because they are insufficiently scientifically researched for their effectiveness to be proven, and furthermore may be harmful in some cases.
Some natural remedies for ED include:
- L-arginine. A natural supplement that may help to widen the blood vessels in the penis, but should not be taken alongside Viagra.
- Ginkgo. A natural supplement that is anecdotally reported, but not scientifically proven, to help improve blood flow to the penis.
- Propionyl L-carnitine. This may be effective when taken alongside Viagra.
However, a doctor should always be consulted before using natural products, particularly in conjunction with other medications to avoid cross-reactivity.
What pills are available to help treat erectile dysfunction?
A: Phosphodiesterase-5 (PDE-5) inhibitors are the most common pill-form drugs that are used to treat erectile dysfunction. Types include:
- Sildenafil. Brand name, Viagra®
- Tadalafil. Brand name, Cialis
- Vardenafil. Brand name, Levitra
- Avanafil. Brand name, Spedra
A doctor should be consulted before using any of these pills as they may be unsuitable in some cases and/or cause intolerable side-effects.
Q: Are erectile dysfunction and premature ejaculation (PE) related?
A: Premature ejaculation ‒ meaning when a person ejaculates more quickly than they would like, i.e. before or very soon after penetration ‒ is one of the two main complaints in male sexual medicine, alongside ED. The two conditions often occur together. When this happens, doctors will usually try to identify and treat the root cause of ED first, with the assumption that PE may get better as a result. If the cause(s) of ED are physical, this is particularly likely to be the case.
If the cause(s) of concurrent PE and ED are psychological in nature, they may be interrelated and reinforce one another. For instance, performance anxiety relating to ED may cause a person to ejaculate prematurely and, likewise, worries related to the possibility of ejaculating prematurely may bring on ED. While medications may be prescribed in some cases, a predominantly psychotherapeutic treatment approach will usually be taken, with a focus on learning behavioral techniques for reducing anxiety around both getting and losing erections.
Q: What are the best ways to deal with erectile dysfunction in a relationship?
A: There are certain ways you can help support a partner who is affected by ED. These include:
- Encouraging them in finding out the root cause by seeking a doctor’s opinion and offering to accompany them to medical appointments.
- Participating as needed in psychotherapy, sex therapy or other treatments which may be recommended for your partner.
- Keeping a dialogue open. Being communicative about your own perspective, empathetic and ready to listen will help a person with ED feel emotionally secure as they begin to explore the reasons for their condition and possible treatment options.
- Not taking a partner’s ED personally. Many partners of people with ED feel that it is a reflection on them, but this is rarely the case. It is important not to cause a person with ED to feel that they have let you down, as this can intensify feelings of related anxiety.
- Finding alternative ways to connect physically and emotionally, thereby taking the emphasis off penetrative sex and reducing a partner’s pressure to perform.
If you think your partner may be experiencing sexual dysfunction, you can get a free symptom assessment at any time by downloading the Ada app.
**How long does erectile dysfunction last after prostate surgery?
A: The sooner after surgery a man begins exploring his erectile abilities, the more likely he is to regain most or all of his normal sexual functionality. This process is called penile rehabilitation. Doctors will usually encourage the affected person to consider resuming sexual activity as soon as the catheter is removed in order to preserve their erectile function.
The success of penile rehabilitation depends foremost on whether or not a man has undergone a nerve-sparing prostatectomy. Non nerve-sparing prostatectomies and unsuccessful nerve-sparing prostatectomies damage the two bundles of nerves associated with producing erections. However, there is a range of different treatments available for ED which may help. (For more information, see the section on treatment.)
**Q: In addition to potential problems getting or maintaining an erection, can a prostatectomy cause any other types of sexual dysfunction?
A: Occasionally, men who have undergone a prostatectomy report experiencing pain when orgasming after they have recovered. It is possible for the pain – which usually affects the perineum and pelvis – to occur either occasionally, at regular intervals or every time the affected person engages in sexual intercourse. The incomplete removal of the seminal vesicles during the prostatectomy procedure is thought to be a principal cause of postoperative pain on orgasming.
In some men, the orgasm ceases to be as intensely pleasurable or ceases to be pleasurable at all. This change in sensation is principally caused by the fact that, in radical prostatectomies, both the glands which make seminal fluid and the vas deferens – the sperm ducts – are no longer operational, so the male orgasm must occur without the ejaculation of semen. Sometimes the semen ejected will not leave the body, but will be transported into the bladder. This is called retrograde ejaculation. This is especially common after a type of surgery called a transurethral resection of the prostate (TURP).
Q: Does masturbating cause ED?
A: No, it is a myth that masturbating itself, even excessively, can cause ED. In fact, after a prostatectomy, a person is actively encouraged by their doctor to resume their sexual practices, including masturbation, as normal in order to restore sexual function.
However, if a person has a particular masturbation technique ‒ i.e. using intensive pressure ‒ then, over time, this may result in problems developing. These may include ED and taking a reduced interest in ‒ or getting reduced satisfaction from ‒ sex. A doctor will therefore take a detailed sexual history when making a diagnosis of ED, in order to find out if a person’s specific habits in this regard have contributed to their condition.
Q: Does porn cause ED?
A: Porn-induced erectile dysfunction is a concept which was first identified by the Kinsey Institute in 2007, soon after internet-based pornography became a worldwide phenomenon. Research suggests a correlation between becoming addicted to watching porn and developing forms of sexual dysfunction, including ED. A recent study indicates that men who masturbate using pornography are at greater risk of developing ED with a partner than those who do not and, when this occurs, cutting out pornography is often recommended as part of the overall treatment approach.
However, the full relationship between watching porn and developing ED is not yet fully understood. Neuroimaging findings suggest that watching porn may have a similarly harmful effect on the brain as that of addictive substances. As their porn habit develops, a person’s neural structure may change, thus increasing their reliance on an external reward system to achieve certain psychological states. This may explain a person’s tendency to depend increasingly on porn for feelings of sexual excitement themselves (rather than being able to generate these mindstates, and associated bodily changes such as erections), and/or to feel the need to seek out media with increasingly extreme subject matter.
- “Erectile Dysfunction (Impotence).” Patient. 01 April 2016. Accessed: 25 August 2017. ↩ ↩ ↩
- “Erectile dysfunction (impotence).” NHS Inform. 07 May 2018. Accessed: 24 December 2018. ↩
- “Management of sexual dysfunction in Parkinson’s disease.” Therapeutic Advances in Neurological Disorders. November 2011. Accessed: 24 December 2018. ↩
- “Sex after stroke.” Stroke Association. November 2017. Accessed: 26 December 2018. ↩
- “Erectile dysfunction and diabetes.” NHS. 21 May 2008. Accessed: 26 December 2018. ↩
- “Treatment of erectile dysfunction in multiple sclerosis.” Expert Review of Neurotherapeutics. June 2006. Accessed: 26 December 2018. ↩
- “Topical Alprostadil (Vitaros©) in the Treatment of Erectile Dysfunction after Non-Nerve-Sparing Robot-Assisted Radical Prostatectomy.” Urologia Journal. 19 February 2018. Accessed: 21 March 2018. ↩ ↩
- “Vitaros 3 mg/g cream.” EMC. 16 November 2017. Accessed: 21 March 2018. ↩ ↩
- “How to use Vitaros: an introductory guide.” Treated.com. 27 November 2017. Accessed: 21 March 2018. ↩ ↩ ↩
- “Erectile dysfunction (impotence).” The British Association of Urological Surgeons. Accessed: 25 August 2017. ↩
- “First genetic risk factor for erectile dysfunction identified.” Science Daily. 08 October 2018. Accessed: 26 December 2018. ↩ ↩
- “Orgasmic Pain and a Detectable PSA Level after Radical Prostatectomy .” Reviews in Urology. 2005. Accessed: 24 December 2018. ↩ ↩
- “Erectile dysfunction (impotence) – Diagnosis](http://www.nhs.uk/Conditions/Erectile-dysfunction/Pages/Diagnosis.aspx).” NHS Choices. 23 September 2014. Accessed: 23 August 2017. ↩
- “Erectile dysfunction (impotence) – Treatment.” NHS Choices. 23 September 2014. Accessed: 28 August, 2017. ↩ ↩
- “Sensate Focus.” Counselling Matters. Accessed: 28 August 2017. ↩
- “The PDE-5 inhibitors.” Sexual dysfunction after radical prostatectomy. Reviews in Urology. 2005. Accessed: 17 January 2019. ↩ ↩
- “Contemporary treatment of erectile dysfunction: a clinical guide.” Humana Press. 2016. Accessed: 17 January 2019. ↩ ↩
- “Alprostadil for erectile dysfunction.” Patient. 22 August 2014. Accessed: 28 August 2017. ↩
- “Alprostadil: side effects.” National Institute for Health and Care Excellence (NICE). 2018. Accessed: 24 December 2018. ↩
- “Preventing Erectile Dysfunction – What You Should Know.” Urology Care Foundation. Accessed: 28 August 2017. ↩
- “A syndrome of erectile dysfunction in young men.” Translational Andrology and Urology. April 2016. Accessed: 26 December 2018. ↩ ↩
- “L-Arginine.” MedicinePlus. 17 October 2018. Accessed: 17 January 2019. ↩
- “Guidelines on male sexual dysfunction: Erectile dysfunction and Premature ejaculation.” European Association of Urology. 2015. Accessed: 26 December 2018. ↩ ↩
- “Behavioural therapies for management of premature ejaculation: a systematic review.” September 2015. Accessed: 26 December 2018. ↩
- “How erection problems can affect your relationship.” Patient. 14 June 2018. Accessed: 26 December 2018. ↩
- “Penile rehabilitation following radical prostatectomy.” Current Opinion in Urology. November 2008. Accessed: 24 December 2018. ↩
- “Does maturbation cause erectile dysfunction (ED)?.” International Society for Sexual Medicine. 2018. Accessed: 26 December 2018. ↩ ↩
- “Sex and relationships.” Prostate Cancer UK. 2018. Accessed: 26 December 2018. ↩
- “Is internet pornography causing sexual dysfunctions? a review with clinical reports.” Behavioural Sciences. September 2016. Accessed: 17 January 2019. ↩
- “Porn use linked to erectile dysfunction.” Medscape. 14 May 2017. Accessed: 17 January 2019. ↩
- “Brain structure and functional connectivity associated with pornography consumption: the brain on porn.” JAMA Psychiatry. 2014. Accessed: 17 January 2019. ↩