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What Is Erectile Dysfunction?

What is Erectile Dysfunction?

Erectile dysfunction is a common issue that affects a significant number of men worldwide. It is defined as the inability to achieve or maintain a satisfactory penile erection for sexual intercourse. This article aims to explore the physiological processes underlying this condition, its various causes, and available treatment options.

What is Erectile Dysfunction?

Erectile dysfunction, or ED, is the most common sex problem that men report to their doctor. It affects as many as 30 million men in USA and more than 150 million worldwide. [1]

An erection that is too weak or difficult to maintain for sexual activity is known as ED.

Although it’s common for men to experience occasional erection issues, ED that progresses or occurs frequently during sex is abnormal and needs to be treated.

ED is possible most frequently when nerves are damaged or penis blood flow is restricted 

with anxiety or other emotional factors in order to serve as a precursor to a more serious condition, such as atherosclerosis (hardening or obstruction of the arteries), heart disease, high blood pressure, or diabetes-related high blood sugar

The Physiology of an Erection

Achieving an erection is complex and involves various physiological and neurological events. In the unstimulated state, penile smooth muscle is contracted, keeping the penis flaccid. Various factors, including noradrenaline, intrinsic myogenic control, and endothelium-derived contracting factors regulate this condition.

Sexual arousal triggers the release of nitric oxide (NO) and acetylcholine, leading to a series of biochemical reactions that relax smooth muscle cells. This relaxation allows blood to fill the corpora cavernosa, a pair of sponge-like regions along the penis. This blood flow compresses the veins, limiting the outflow of blood and causing an erection [2]

Understanding Erectile Dysfunction

Erectile dysfunction occurs when any stage of this complex process is disrupted. It can be broadly classified into organic and non-organic (or psychogenic) types.

Non-Organic Erectile Dysfunction

Non-organic erectile dysfunction is often related to psychological factors such as stress, anxiety, and depression.[3]. These psychological conditions can interfere with the normal erectile process, leading to performance anxiety and fear of failure.

Organic Erectile Dysfunction

Organic erectile dysfunction, on the other hand, is caused by physical or physiological conditions. These can be categorized into neurogenic, vasculogenic, iatrogenic, and endocrine causes. [4]

Neurogenic Causes

Neurogenic erectile dysfunction is caused by nerve damage responsible for penile erection. This damage can result from conditions like spinal cord injury, multiple sclerosis, Parkinson’s disease, and diabetes. [5]

Vasculogenic Causes

Vasculogenic erectile dysfunction is related to issues with blood flow to the penis. Conditions such as hypertension, diabetes, dyslipidemia, and lifestyle factors like smoking can lead to this type of dysfunction. [6]

Iatrogenic Causes

Iatrogenic erectile dysfunction refers to the condition caused by medical treatments or procedures. For instance, radical pelvic surgery, certain medications used to treat hypertension, and other conditions can lead to erectile dysfunction. [7]

Endocrine Causes

Endocrine causes of erectile dysfunction are related to hormonal imbalances, especially testosterone levels. While the role of testosterone in erectile function is well established, the impact of testosterone replacement therapy in men with erectile dysfunction is a subject of ongoing research. [8]

Symptoms of Erectile Dysfunction

Common ED symptoms include:

  • Difficulty getting an erection; 
  • Trouble keeping an erection during sexual intercourse;
  • Premature ejaculation;
  • Delayed ejaculation;
  • Decreased sexual desire;
  • Absent or less intense orgasms; 

Treatment Options for Erectile Dysfunction

Various treatment options are available for erectile dysfunction, ranging from lifestyle changes and oral medications to surgery. The treatment choice depends on the condition’s underlying cause and the patient’s overall health status.

Lifestyle Changes

Lifestyle changes can have a significant impact on erectile function. These include regular exercise, a healthy diet, quitting smoking, and limiting alcohol intake [9]


Several oral medications are available for treating erectile dysfunction. These include PDE5 inhibitors like Sildenafil (Viagra), Tadalafil (Cialis), Vardenafil (Levitra) and Avanafil (Stendra). These medications enhance the effects of nitric oxide, a natural chemical the body produces to relax muscles in the penis and increase blood flow.

Surgical Treatments

In cases where medication is not effective or suitable, surgical treatments may be considered. These include penile implants and vascular surgery.


Erectile dysfunction is a complex condition with various underlying causes. Understanding these causes and the physiological processes involved in achieving an erection is crucial for effective treatment. With various treatment options, most men can find a solution that works for them.


1. 1.McKinlay JB. The worldwide prevalence and epidemiology of erectile dysfunction. Int J Impot Res. 2000 Oct;12 Suppl 4:S6-S11.

2. 2. Lue TF, Tanagho EA. Physiology of erection and pharmacological management of impotence. J Urol. 1987;137:829–836.

3. 3.McCabe MP, Althof SE. A systematic review of the psychosocial outcomes associated with erectile dysfunction: does the impact of erectile dysfunction extend beyond a man’s inability to have sex? J Sex Med. 2014;11:347–363.

4. 4. Gandaglia G, et al. A systematic review of the association between erectile dysfunction and cardiovascular disease. Eur Urol. 2014;65:968–978.

5. 5.Brackett NL, Lynne CM, Ibrahim E, Ohl DA, Sonksen J. Treatment of infertility in men with spinal cord injury. Nat Rev Urol. 2010;7:162–172.

6. 6.Kupelian V, Araujo AB, Chiu GR, Rosen RC, McKinlay JB. Relative contributions of modifiable risk factors to erectile dysfunction: results from the Boston Area Community Health (BACH) Survey. Prev Med. 2010;50:19–25.

7. 7.Esposito K, et al. Dietary factors in erectile dysfunction. Int J Impot Res. 2006;18:370–374.

8. 8.Baskin LS, et al. The effect of testosterone on androgen receptors and human penile growth. J Urol. 1997;158:1113–1118.

9. 9.Maiorino MI, Bellastella G, Esposito K. Lifestyle modifications and erectile dysfunction: what can be expected? Asian J Androl. 2015;17:5–10.

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