What is erectile dysfunction (ED)?

Medically, erectile dysfunction is defined as the inability to both achieve and maintain a penile erection adequate for satisfactory sexual intercourse.ⁱ The condition is one of the most common sexual function problems that affect the male population and is more prevalent among older men. However, a man of any age can experience ED. Occasionally, ED is referred to as impotence, even though this is now considered an outdated term. There is a high prevalence of ED in the general population. A study of men in the US showed that the prevalence of ED in men ≥ 20 years of age was 18.4 percent.ⁱⁱ

Erectile dysfunction is more common as men age, and increasing age is the principal risk factor for ED.ⁱⁱⁱ While the range in the literature is variable, one study of 2 156 men found that 5 percent of men between the ages of 20 and 39 had ED, compared to 70 percent of men aged 70 and older.^iv Globally, the number of men with ED is increasing, which is thought to be due to the aging population.

Although the incidence of ED increases with age, a study of 439 patients found that 26 percent of men seeking medical attention for ED were ≤ 40 years old.^v Experiencing ED on occasion is not uncommon for any man. For example, some men may have ED symptoms during stressful times or due to performance anxiety. However, if ED occurs on a regular basis, that person may need medical treatment and could have underlying health problems that need to be addressed by a health care provider.

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What are the symptoms of erectile dysfunction?

The main symptom of ED is the inability to achieve or maintain an erection that is of sufficient rigidity or duration for sexual intercourse.^vi

Some men also have secondary issues due to the inability to keep an erection firm enough to perform sexually. For example, most men with ED experience symptoms of anxiety or depression because of their perceived lacking sexual performance.^vii This can have a detrimental effect on the quality of life of both the patient as well as any current or potential partners.  

While not a symptom of ED itself, ED is commonly associated with lower urinary tract symptoms in patients with a large prostate gland.^viii This is usually caused by the non-cancerous enlargement of the prostate (called benign prostatic hyperplasia [BPH]), a condition which is common in older men. Lower urinary tract symptoms include urinary hesitancy, poor or intermittent stream, straining, and incomplete emptying. These symptoms occur due to the enlarged prostate partially blocking the urethra, the tube that carries urine and semen. ED can also be associated with cardiovascular issues, as discussed below.

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What causes erectile dysfunction?

Erectile dysfunction causes can be both physical and psychological in nature. Everything from emotional factors such as relationship problems with a sexual partner to physical factors that include taking certain prescription medication can be involved.

Erectile dysfunction is classified as organic, psychogenic, or mixed (both organic and psychogenic). Organic ED refers to a condition which has an underlying physical cause, while psychogenic ED refers to a condition which has a psychological origin. Organic causes of ED are thought to account for over 80 percent of cases, though psychogenic ED is more common in younger men.^ix

Organic causes of ED^x

• Vasculogenic causes: This refers to damage to the arteries or veins (vascular system), and this is the most common cause of ED. Because increased blood flow to the penis is important for erectile function, damage to or blockage of the blood vessels supplying the penis are often linked to ED. Atherosclerosis, or the build-up of plaques in the arteries which can lead to blockage and low flow, can contribute to ED. Atherosclerosis can occur in vessels throughout the body, which is why ED is associated with other cardiovascular problems such as heart attacks and strokes. Pelvic trauma or injury can also prevent penile veins from “closing off” outflow during an erection which can also cause ED. Direct penile trauma such as a penile fracture or a priapism (erection lasting longer than 4 hours) can lead to permanent vascular injury to the penis which can also cause ED.

• Neurogenic causes:  Neurogenic ED is caused by a dysfunction of the nervous system. This may be related to the central nervous system (brain or spinal cord) or to the peripheral nervous system (nerves that come out of the spinal cord). Common central nervous system causes of ED include a spinal cord injury or surgery, stroke, epilepsy, Parkinson’s disease, or Multiple Sclerosis. Pelvic surgery (such as prostate removal) and diabetes are two causes of peripheral nerve damage that can cause erectile dysfunction.  
• Endocrinological causes:  Dysfunction or dysregulation of the endocrine system, which controls hormones in the body, can cause ED. Some common causes include diabetes (which can also cause neurogenic ED), low testosterone, or hyperprolactinemia. Hyperprolactinemia results in an increased level of the hormone prolactin, which is produced in the brain and induces lactation. Patients with chronic systemic illnesses such as liver or kidney failure can also have related problems with their endocrine systems (such as low testosterone) that can lead to ED. Finally, obesity is associated with low testosterone and resultant ED.^xi‍
• Drug-induced causes:  Certain medications and recreational drugs can contribute to ED. Prescription medications such as anti-androgens (e.g., GnRH agonists, spironolactone), antihypertensives (e.g., thiazide diuretics), antiarrhythmics (e.g., digoxin), statins, and antidepressant medications (e.g., SSRIs, TCAs) can lead to ED. Recreational drugs such as marijuana, opiates, cocaine, nicotine, and alcohol are also associated with ED.

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Psychogenic causes of ED

Psychogenic causes often involve a complex interaction of psychological factors. Some factors which may contribute include:^xii

• Traumatic past experiences
• Acute relationship problems
• Performance anxiety
• Major life stressors
• Mental health conditions

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How is erectile dysfunction diagnosed?

Diagnosis of erectile dysfunction is typically accomplished through a thorough history and physical examination.  

The full testing process may involve everything from discussing medical history and sexual history with a health professional to undergoing blood tests or imaging studies that may indicate signs of physical problems.

Medical history assessment

During a medical history assessment, a physician will take a detailed medical history from the patient and will ask questions pertaining to ED. These questions are also useful to distinguish between ED and other types of sexual dysfunction, such as decreased libido or premature ejaculation. In addition, the assessment can determine the presence of risk factors for other diseases that can cause ED, such as diabetes or cardiovascular disease.^xiii A psychological assessment may also be warranted, as psychological factors often contribute to ED. This may involve discussing interpersonal conflict or relationship factors that may influence ED.

During the assessment, the care provider may also look at what oral medications the patient may be taking, including over-the-counter drugs. Lifestyle factors are often discussed as well, relative to issues such as regular exercise or nutritional habits.  

International Index of Erectile Function (IIEF) or Sexual Health Inventory for Men (SHIM) screening

A validated screening tool such as the International Index of Erectile Function (IIEF) or Sexual Health Inventory for Men (SHIM) may also be used to detect ED.^xiv The IIEF is a self-administered questionnaire consisting of 15 questions answered by the patient, while the SHIM is a modified, 5-question version of the survey.^xv A sexual history may also be obtained through a validating screening tool such as the Brief Sexual Symptom Checklist.^xvi

Physical exam and other testing for ED  

The physical examination involves evaluating the genitals, including the penis and scrotum, for lesions, scars, and plaques, as well as the positioning of the urethral opening (where urine and semen exit the body).^xvii During the exam, the physician will also evaluate the size of the testicles and look for any other changes. It may also include an evaluation of the cardiovascular system and screen for physical indicators of decreased testosterone or hyperprolactinemia.

Blood tests may be performed to examine biological markers for underlying conditions such as low testosterone or other hormonal changes.

In some cases, additional testing may be recommended to determine the cause of ED. A nocturnal penile tumescence (NPT) test may be performed during a sleep study to determine how many erections a man has while he is asleep. If a man is not having natural erections during sleep, this can be an indicator of erectile dysfunction. NPT is not commonly performed currently due to difficulty administering the test and a high rate of false negatives.

Other testing includes a penile injection (called an intracavernosal injection [ICI]) administered in the doctor’s office with a medicine to stimulate erection. This can allow physicians to determine the cause of ED and to assess for penile curvature (Peyronie’s disease). A special ultrasound test called a penile duplex ultrasound may also be used to assess for blood flow to and from the penis before and during the induced erection.^xviii

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How does erectile dysfunction impact fertility?

Fertility may be affected by ED, especially in more severe cases in which it is an ongoing problem. Even though an erection is not necessarily required for ejaculation to occur, erectile failure can inhibit sufficient penetration. Erectile dysfunction is classified as a sperm transport disorder.^xix If the ED is severe, resulting in an absent erection or consistent inability to achieve an erection sufficient for penetrative intercourse, sperm transport to a partner’s vagina will be impaired, thereby impeding conception. A 2018 study of 4 299 Chinese men found that 34.9 percent of men in infertile couples had mild ED and 2.6 percent had severe ED, according to IIEF criteria.^xx

The inability to release semen (which contains sperm) effectively in cases of erectile dysfunction can decrease fertility, even though the ability to produce sperm is not usually impaired. Patients with impaired erectile function also have higher odds of less frequent sexual intercourse, which is associated with reduced fertility.^xxi

While fertility can be affected by erectile dysfunction, many couples do see success with one of the available treatment options for ED. Many men with ED have underlying health problems that can be addressed successfully, and lifestyle changes can also make a drastic difference.

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What ED treatment options are available and how successful are they?

Seeking treatment for ED can be intimidating, but several treatment options have been shown to be effective for helping a man achieve an erection that is satisfactory for sexual intercourse. Doctors treat erectile dysfunction according to the underlying cause, and some men will need a multifaceted approach to achieve the best treatment outcomes.

Treatment of Organic ED

Pharmacotherapy

Certain prescription medications or types of drug therapy may be effective for treating erectile dysfunction and increasing blood flow to the penis. Oral phosphodiesterase-5 (PDE5) inhibitors are considered the first-line treatment for ED and are generally held to be a very successful form of treatment.^xxii They work by causing smooth muscle relaxation which dilates the blood vessels of the penis, allowing for increased blood flow to generate a rigid erection with sexual stimulation.^xxiii The major PDE5 inhibitors are sildenafil (Viagra®), tadalafil (Cialis®), vardenafil (Levitra®), and avanafil (Stendra®).^xxiv A study on sildenafil amongst men with infertility showed that it significantly improved erectile function and improved ejaculatory dysfunction by 64 percent.^xxv

While effective, prescription drugs do not help with sexual arousal directly, only sexual function, and must be taken in combination with sexual stimulation in order to work. However, many men find that once they are able to get an erection with the help of a prescription drug, the sexual arousal aspect comes more naturally, and ejaculation is easier because sensitivity is enhanced with better blood flow.

Lifestyle changes

Lifestyle modifications, including smoking cessation, decreasing alcohol intake, weight loss, and increasing physical activity have been shown to improve erectile function,^xxvi though they may take up to two years to do so.^xxvii

If a health care provider does provide medical advice that involves making lifestyle changes, these recommendations should be taken seriously.  

Dietary supplements

Some dietary supplements may offer noteworthy benefits for men who have ED, even though the results can vary depending on the formula.

One example of a dietary supplement for ED is L-arginine, a vasodilator that may help open blood vessels and encourage blood flow to the penis. Arginine has been shown to be a promising supplement option for ED, but further research is needed.^xxviii

Procedural and other types of therapy

Intracavernosal injection (ICI) and transurethral therapy are types of therapy that can be tried if patients do not have success with oral PDE5 inhibitors. This is the same type of ICI used to help evaluate the nature of the ED during testing, involving an injection of medication directly into the penis. There are a variety of different agents that can be used, and, depending on the medication used, ICI is up to 90 percent effective in treating ED. Muse (c) (prostaglandin E1 suppository) is a small suppository tablet that is inserted into the urethra by the patient that can also be effective in treating ED in patients unable to achieve erections with oral medications.^xxix

Another option is a vacuum constrictive device, which brings blood supply into the penis and constricts the base of the penis with an elastic band to retain blood and allow for an erection. While vacuum and constrictive devices do change how blood flows to the erection chambers of the penis and may create a temporary erection, the risk of blood vessel or nerve damage with improper use may exacerbate the problem over time. Therefore, men should seek medical advice, use caution, and invest in quality-made devices when using vacuum pumps or constricting bands to treat ED.

A penile prosthesis is regarded as a surgical treatment of last resort for ED. It involves a surgical procedure in which a penile prosthesis is inserted inside the penis. The device can be inflatable, with a pump in the scrotum that is used to inflate the device with fluid to achieve an erection. There are also malleable devices, which are not inflatable and are always in a semi-rigid state. Patient satisfaction rates are over 90 percent for treating ED with an inflatable penile prosthesis.^xxx Because penile prosthesis implantation requires surgery and involves the permanent insertion of an artificial device, there are potential risks. The most common risks include bleeding, infection of the device, migration of the device including erosion into the urethra or skin, device failure, and penile shortening or pain. As the inflatable devices are mechanical, they can also fail with time and may need to be replaced.  

Finally, testosterone therapy or other hormonal therapies may be recommended if blood tests reveal low testosterone levels. Often, if a patient has low testosterone as a cause for his ED, he will also have additional symptoms of low testosterone including low libido (desire for intercourse) and fatigue. Even though low testosterone can be linked to ED, low testosterone or other endocrine i system disorders are one of the rarer causes.^xxxi  It is important to note that treatment of low testosterone with testosterone therapy can cause male infertility. If a patient has low testosterone and wishes to preserve his fertility, alternate treatments with different hormonal medications (such as selective estrogen receptor modulators, gonadotropins or aromatase inhibitors) are typically prescribed.^xxxii

Treatment of Psychogenic ED

Psychogenic ED is best treated with psychological interventions. Patients meeting clinical criteria for anxiety or depression may benefit from pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs). However, SSRIs are concurrently a risk factor for the development of ED. A 2016 study suggests that adding an additional medication, bupropion, may improve sexual dysfunction associated with SSRIs.^xxxiii  

Additionally, psychotherapy may improve ED., and there is clinical evidence to suggest that group psychotherapy can be helpful.^xxxiv Men who have experienced past trauma, have been diagnosed with a mental health condition such as depression, or otherwise struggle with sexual arousal may benefit from seeking help from a mental health professional.

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What other risks/complications are associated with erectile dysfunction?

Men who deal with erectile failure due to ED can face further risks beyond just the physical side effects or problems with sperm delivery. Erectile dysfunction has a significant psychosocial impact on patients and has been shown to be seriously distressing to those who experience it.^xxxv These impacts include lower self-esteem as well as a negative effect on the relationships of men with ED.

In addition, erectile dysfunction may be the first evident symptom of cardiovascular disease. Men with ED have a higher risk of cardiovascular events compared to men without ED.^xxxvi A 2013 systematic review indicated that ED can be a predictor of heart disease, and the study authors proposed that ED and cardiovascular disease should be considered as two different manifestations of the same overall disorder.^xxxvii

Relatedly, a meta-analysis of 92 757 patients across 14 studies showed that patients with ED had a 62 percent increased risk of heart attacks (myocardial infarction), and 25 percent increased overall mortality compared to people who did not have ED.^xxxviii Because of this, men with ED often require a cardiovascular work-up to rule out concurrent cardiovascular disease.^xxxix

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Conclusion

While ED is an especially common sexual health problem for men, the condition is one that is highly treatable. ED can impact fertility, but primarily in an indirect way due to the physical inability to maintain an erection for ejaculation or sperm delivery.

If a man suspects that he has ED, seeking medical advice is always recommended. ED can be an indication of other health problems, such as high blood pressure or another vascular disease, heart disease, or even prostate problems. Everything from prescription drugs to penile implants may be used to treat ED, and some medical and over-the-counter treatments are more effective than others.

Anyone experiencing ED that is interfering with the ability to conceive should be sure to talk to a doctor who can provide medical advice, discuss options, and potentially help find a solution.