Erectile Dysfunction
Also known as: Erectile Dysfunction (ED)
Erectile dysfunction (ED) is the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It is one of the most common sexual health conditions in men, affecting an estimated 30 million men in the United States. While occasional difficulty with erections is normal, persistent ED can be a sign of underlying health problems — particularly cardiovascular disease — and should be evaluated by a healthcare provider.
In this article
What Is Erectile Dysfunction?
An erection is a complex neurovascular event that requires coordinated interaction between the nervous system, blood vessels, hormones, and psychological state. During sexual arousal, nerve signals trigger the release of nitric oxide (NO) in the corpus cavernosum of the penis. NO activates a cascade that produces cyclic GMP (cGMP), which relaxes smooth muscle cells and allows blood to fill the penile sinusoids. Compression of the subtunical venules traps blood, creating rigidity.
Erectile dysfunction occurs when any component of this process is impaired — whether vascular, neurologic, hormonal, or psychological.
ED Classification
- Organic (physical): Caused by vascular, neurologic, hormonal, or structural factors. Accounts for approximately 80% of cases.
- Psychogenic: Caused by psychological factors such as performance anxiety, depression, stress, or relationship issues.
- Mixed: A combination of organic and psychogenic factors — the most common presentation in clinical practice.
Causes
Vascular Causes (most common)
- Atherosclerosis (hardening and narrowing of arteries)
- Hypertension
- Diabetes mellitus (causes both micro- and macrovascular damage)
- Dyslipidemia (high cholesterol)
- Peripheral vascular disease
- Venous leak (failure to trap blood in the corpora)
Neurologic Causes
- Diabetic neuropathy
- Spinal cord injury
- Multiple sclerosis
- Radical prostatectomy or pelvic surgery (nerve damage)
- Parkinson disease
- Stroke
Hormonal Causes
- Low testosterone (hypogonadism)
- Hyperprolactinemia
- Thyroid disorders
- Cushing syndrome
Medication-Related
- Antihypertensives (especially thiazide diuretics and beta-blockers)
- Antidepressants (SSRIs, SNRIs)
- Antiandrogens (finasteride, spironolactone)
- Opioids
- Alcohol and recreational drugs
Psychological Causes
- Performance anxiety
- Depression
- Relationship conflict
- Chronic stress
- History of sexual trauma
Risk Factors
The risk of ED increases with age but is not an inevitable consequence of aging. The strongest risk factors mirror those of cardiovascular disease:
- Age: Prevalence increases from ~12% at age 40 to ~50% by age 70.
- Cardiovascular disease: ED shares the same underlying endothelial dysfunction as coronary artery disease.
- Diabetes: Men with diabetes are 3x more likely to develop ED and tend to develop it 10-15 years earlier.
- Obesity: Men with a BMI >30 have a 1.5-3x increased risk of ED.
- Smoking: Doubles the risk of ED through vascular damage.
- Physical inactivity: Sedentary lifestyle is an independent risk factor.
- Depression: Both a cause and consequence of ED — bidirectional relationship.
- Low testosterone: Present in approximately 30% of men with ED.
The Cardiovascular Connection
ED is now recognized as an early warning sign of cardiovascular disease. The penile arteries are smaller (1-2 mm) than coronary arteries (3-4 mm), so atherosclerotic changes manifest as ED before they cause angina or heart attack. Studies show ED precedes a cardiovascular event by an average of 2-5 years. All men with new-onset ED should be screened for cardiovascular risk factors.
How It Is Diagnosed
Diagnosis of ED is primarily clinical, based on a thorough sexual, medical, and psychosocial history. Standardized questionnaires and targeted lab work help characterize the severity and underlying cause.
Clinical Evaluation
- Sexual history: Onset (gradual vs. sudden), presence of morning erections, situational vs. global, relationship factors.
- IIEF-5 / SHIM questionnaire: Standardized 5-question assessment that scores ED severity (mild, moderate, severe).
- Medical history: Cardiovascular risk factors, diabetes, neurologic conditions, medications, surgeries.
- Physical examination: Genital exam, assessment of secondary sexual characteristics, vascular exam, neurologic screening.
Laboratory Testing
- Fasting glucose and HbA1c (diabetes screening)
- Lipid panel
- Total and free testosterone (morning draw)
- TSH (thyroid function)
- CBC
- Prolactin (if testosterone is low or libido is severely decreased)
Specialized Testing (when indicated)
- Nocturnal penile tumescence (NPT) testing — differentiates organic from psychogenic ED
- Duplex Doppler ultrasonography — evaluates penile blood flow
- Intracavernosal injection test — assesses vascular response
When to See a Doctor
You should consider seeing a healthcare provider if:
- You consistently have difficulty achieving or maintaining erections over a period of several weeks
- ED is causing distress, anxiety, or relationship problems
- You have diabetes, heart disease, or other known risk factors
- You notice a sudden onset of ED (may indicate a vascular or neurologic event)
- You also experience decreased libido, fatigue, or other symptoms suggesting hormonal imbalance
- ED developed after starting a new medication
ED is highly treatable. The first step is identifying the underlying cause through a proper medical evaluation. Many men delay seeking care due to embarrassment, but ED is a legitimate medical condition that affects millions and has effective, evidence-based treatments.
Related Conditions
Medical disclaimer: This article is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read on this website.
Medically reviewed. Last updated: March 2026.