Erectile Dysfunction: The Complete Guide to Causes, Evaluation, and Treatment

Let's skip the euphemisms. Erectile dysfunction — the consistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance — affects approximately 50% of men between ages 40 and 70. It's one of the most common conditions in men's health, and one of the least honestly discussed.

Most men who experience ED don't bring it up with their doctor. They quietly order pills from dubious online sources, convince themselves it's temporary, or stop initiating sex entirely. Their partners fill in the gaps with assumptions — usually wrong ones. The relationship suffers. Self-esteem craters. And a potentially important medical signal goes uninvestigated.

Because here's what many men don't know: erectile dysfunction is often the first clinical sign of cardiovascular disease.

How Erections Work (The Short Version)

An erection is a vascular event. Sexual stimulation triggers nitric oxide release from nerve endings and endothelial cells in the penis. Nitric oxide activates an enzyme (guanylate cyclase) that produces cyclic GMP (cGMP), which relaxes smooth muscle in the penile arteries. Blood rushes in, fills the corpora cavernosa, and compresses the veins against the tunica albuginea — trapping blood and creating rigidity.

Anything that impairs blood flow, nerve signaling, smooth muscle function, or the nitric oxide pathway can cause ED.

Causes: Why It Happens

Vascular (Most Common)

The penile arteries are 1-2mm in diameter — significantly smaller than coronary arteries (3-4mm). Atherosclerosis affects small arteries first. This is why ED often precedes heart attacks and strokes by 3-5 years. A man with new-onset ED and no other symptoms should be evaluated for cardiovascular risk.

• Atherosclerosis — Plaque buildup reduces blood flow
• Hypertension — Both the condition and many antihypertensive medications impair erections
• Diabetes — Damages both blood vessels and nerves; ED prevalence in diabetic men is 35-75%
• Dyslipidemia — High cholesterol contributes to endothelial dysfunction
• Smoking — Doubles ED risk through vascular damage
• Obesity — Inflammation, endothelial dysfunction, and low testosterone

Neurological

• Diabetes-related neuropathy — Damages the nerves that signal nitric oxide release
• Spinal cord injury
• Multiple sclerosis
• Post-surgical — Radical prostatectomy or pelvic surgery can damage erectile nerves
• Parkinson's disease

Hormonal

• Low testosterone — Contributes to reduced libido more than erectile mechanics, but severe deficiency impairs erections
• Hyperprolactinemia — Elevated prolactin suppresses sexual function
• Thyroid disorders — Both hypo- and hyperthyroidism affect sexual function

Psychological

• Performance anxiety — The most common psychological cause. Once a man fails to achieve an erection, anxiety about the next attempt creates a self-fulfilling prophecy.
• Depression — Directly reduces libido and erectile function
• Relationship conflict — Unresolved tension, resentment, or communication breakdown
• Stress — Chronic stress elevates cortisol, which suppresses testosterone and constricts blood vessels
• Porn-related ED — Controversial but increasingly recognized. Habitual pornography use may condition arousal to specific stimuli that don't transfer to partnered sex.

Medication-Induced

Common offenders include:

• SSRIs (fluoxetine, sertraline, paroxetine) — 30-70% of users experience sexual dysfunction
• Beta-blockers (atenolol, metoprolol) — older beta-blockers are worse; nebivolol may be ED-neutral
• Thiazide diuretics
• Spironolactone — anti-androgen effects
• 5-alpha reductase inhibitors (finasteride, dutasteride) — can persist after discontinuation in some men
• Opioids — suppress testosterone
• Antihistamines — in some men
• Antipsychotics

The Evaluation

A proper ED evaluation isn't just measuring testosterone. It should include:

• Detailed history — Onset (sudden vs. gradual), situational vs. global, morning erections, libido, relationship factors, stress, medication review
• Cardiovascular risk assessment — Blood pressure, lipid panel, fasting glucose/A1c, BMI, smoking history, family history
• Hormone panel — Total and free testosterone (morning draw), prolactin if testosterone is low
• Thyroid function — TSH
• Additional labs as indicated — PSA, CBC, metabolic panel

Key clinical clue: If a man has normal spontaneous erections (morning erections, erections with self-stimulation) but can't maintain erections with a partner, the cause is more likely psychological. If erections are diminished across all situations, the cause is more likely organic (vascular, neurological, or hormonal).

At CORAL, Dr. Kim performs a comprehensive ED evaluation that addresses both the sexual dysfunction and the underlying health signals it may represent.

Treatment

Lifestyle Modifications (Don't Skip This Section)

Before reaching for a pill, modifiable risk factors should be addressed:

• Exercise — Regular aerobic exercise improves endothelial function and erectile function. A meta-analysis showed 160 minutes of weekly aerobic exercise for 6 months significantly improved ED in men with cardiovascular risk factors.
• Weight loss — Losing 5-10% of body weight can improve erectile function in overweight men.
• Smoking cessation — Improves vascular function within weeks.
• Alcohol moderation — Chronic heavy drinking impairs erections through multiple mechanisms. Moderate drinking (1-2 drinks) may have less impact.
• Sleep — Treat sleep apnea (strongly associated with ED) and prioritize sleep quality.
• Stress management — Address chronic stress through exercise, therapy, or other evidence-based approaches.

These aren't just complementary — for men with mild ED and modifiable risk factors, lifestyle changes alone may be sufficient.

PDE5 Inhibitors (First-Line Medication)

Phosphodiesterase type 5 inhibitors block the enzyme that breaks down cGMP — the molecule that causes smooth muscle relaxation and blood flow into the penis. They amplify the natural erectile response; they don't create erections from nothing. Sexual stimulation is still required.

Sildenafil (Viagra): The original. Onset 30-60 minutes. Duration 4-6 hours. Affected by fatty meals (delays absorption). Take on an empty stomach for best results.

Tadalafil (Cialis): Longer acting — 24-36 hours ("the weekend pill"). Available in daily dosing (2.5-5mg) for spontaneous readiness. Not affected by food. Also FDA-approved for BPH (may help men with both conditions).

Vardenafil (Levitra/Staxyn): Similar to sildenafil in onset and duration. Orally disintegrating tablet (Staxyn) available. Slightly less affected by food than sildenafil.

Avanafil (Stendra): Fastest onset (15-30 minutes). Shortest duration. Most selective for PDE5 (fewer off-target side effects). Less affected by food.

Common side effects across the class: Headache, flushing, nasal congestion, dyspepsia, visual changes (sildenafil). Usually mild and diminish with continued use.

Contraindications: Concurrent use with nitrates (nitroglycerin, isosorbide) — can cause life-threatening hypotension. Caution with alpha-blockers (use low starting dose).

Failure rate: About 30% of men don't respond to PDE5 inhibitors. Often this is due to incorrect use (not enough time, not enough stimulation, taking with heavy meals) rather than true treatment failure.

Second-Line Options

Vacuum erection devices — External pump creates negative pressure, drawing blood into the penis. A constriction band at the base maintains the erection. Effective but cumbersome. No medications required.

Intracavernosal injections (alprostadil/trimix) — Self-injection directly into the corpora cavernosa. Highly effective (85-90% response rate) in men who fail PDE5 inhibitors. Produces an erection regardless of arousal. Requires instruction and comfort with self-injection.

Intraurethral alprostadil (MUSE) — Pellet inserted into the urethra. Less effective than injection but less invasive.

Testosterone replacement — When ED is accompanied by low testosterone and low libido, TRT may improve both desire and erectile function. Often combined with a PDE5 inhibitor.

Third-Line: Penile Prosthesis

For men who fail all other treatments, surgical implantation of a penile prosthesis (inflatable or semi-rigid) provides reliable erections. Patient satisfaction rates are among the highest of any surgical procedure (90-95%). This is a permanent solution but requires surgery.

When to Get Help

If you're experiencing ED, get evaluated — not just treated. The easy path is ordering pills online without seeing a doctor. The smart path is understanding why your erections are failing, because the answer might save more than your sex life.

[Start a visit at coral.clinic/start](https://coral.clinic/start). Dr. Kim provides comprehensive, discreet ED evaluations and treatment via telehealth. No waiting room. No awkward small talk. Just evidence-based medicine for a problem that has solutions.