Erectile Dysfunction: Causes, Diagnosis & Treatment Options

What is erectile dysfunction?

Erectile dysfunction is the persistent inability to get or maintain an erection firm enough for satisfying sex. Occasional difficulty is normal and usually reflects stress, fatigue, or alcohol. ED is diagnosed when the problem is consistent over roughly three months or longer and is causing distress.

An erection depends on three systems working together: healthy arteries delivering blood, intact nerves signaling the response, and adequate hormone levels driving desire. It also requires the veins to trap blood once it arrives. A problem in any of these can produce ED — which is why identifying which one matters more than reaching immediately for a prescription.

Is erectile dysfunction a warning sign of heart disease?

Often, yes. ED and coronary artery disease share the same underlying process — endothelial dysfunction and atherosclerosis. Because the arteries supplying the penis are considerably narrower than the coronary arteries, they tend to show narrowing earlier. New ED in a man over 40 can precede a cardiac event by several years.

This is the most important thing on this page, and it is frequently left out of ED discussions entirely.

Practically, it means that a proper ED evaluation is partly a cardiovascular evaluation. A man presenting with new ED should have his blood pressure, cholesterol, blood glucose or A1c, and weight assessed, and should be asked about smoking, exercise, and family history. For a meaningful number of men, the ED appointment is where undiagnosed diabetes, hypertension, or dyslipidemia is first identified.

It also means the reverse is worth saying: treating ED with a pill alone, without asking why it happened, misses an opportunity. The same lifestyle changes that improve erections — exercise, weight loss, smoking cessation, better glucose and blood pressure control — improve cardiovascular outcomes. That is not a coincidence; it is the same disease.

What causes erectile dysfunction?

Most ED in men over 40 is at least partly vascular. But causes commonly overlap, and psychological factors accompany physical ones more often than not.

Vascular causes — atherosclerosis, high blood pressure, high cholesterol, diabetes, smoking, obesity, and metabolic syndrome. The largest category by far.

Neurologic causes — diabetic neuropathy, multiple sclerosis, Parkinson’s disease, stroke, spinal cord injury, and nerve damage from pelvic surgery or radiation.

Hormonal causes — low testosterone, thyroid disorders, and elevated prolactin. Low testosterone more often reduces desire than directly impairs erections, which is a distinction worth making.

Medication-related causes — a genuinely long list, including many blood pressure medications (particularly beta blockers and thiazide diuretics), SSRIs and other antidepressants, some antipsychotics, opioids, and 5-alpha reductase inhibitors used for BPH and hair loss. Never stop a prescribed medication on your own — but do bring a complete list to your appointment, because substitution often solves the problem.

Peyronie’s disease — fibrous scar plaque forming in the tunica albuginea, the tissue layer surrounding the erectile chambers. It causes penile curvature, pain with erection, and sometimes shortening, and can interfere with erectile function. It is a specific condition with specific treatments, not simply "scar tissue on the skin."

Psychological and relationship factors — performance anxiety, depression, stress, and relationship difficulty. These are real causes, not lesser ones, and they frequently coexist with physical causes. A man with mild vascular ED can develop severe functional ED once anxiety compounds it.

Lifestyle factors — smoking, heavy alcohol use, recreational drug use, sedentary living, poor sleep, and untreated sleep apnea.

Prostate cancer treatment — surgery, radiation, and hormone therapy all affect erectile function through different mechanisms. Covered in its own section below.

Erectile dysfunction after prostate cancer treatment

For men treated for prostate cancer, ED is the most common long-term concern, and it deserves a fuller answer than most sites provide.

After surgery. The nerves controlling erections run immediately alongside the prostate. Even when they are preserved during a nerve-sparing prostatectomy, they are stretched and traumatized during the operation, and nerve tissue recovers slowly. Erectile function typically declines sharply immediately after surgery and then recovers gradually over 12 to 24 months. Recovery depends heavily on your erectile function before surgery, your age, whether both nerve bundles could be spared, and your vascular health. Men who understand the timeline going in cope with it considerably better than men who expect to be back to normal in a month.

After radiation. The decline is typically slower and more gradual, often beginning months to years after treatment, since radiation affects blood vessels and nerves progressively.

After hormone therapy (ADT). Androgen deprivation reduces both desire and erectile capacity, and effects generally persist while treatment continues. Recovery after stopping depends on duration of therapy and age.

Penile rehabilitation

The principle is that erectile tissue deprived of regular oxygenated blood flow can undergo fibrotic change over time — so the goal is to maintain blood flow during the recovery window rather than simply waiting.

Approaches typically include daily or on-demand PDE5 inhibitors started early after surgery, vacuum erection devices, and injection therapy when pills alone are insufficient. Evidence for the various protocols is mixed and no single regimen is universally established, but the general strategy is widely used and reasonable, and starting early appears to matter.

The practical point: do not wait a year to raise this. Discuss rehabilitation before surgery if possible, and start it in the early recovery period. Learn about prostate cancer treatment →

How is erectile dysfunction diagnosed?

Evaluation is usually straightforward and does not require invasive testing for most men.

• Sexual history, often using a validated questionnaire such as the IIEF or its short form, the SHIM, which gives a baseline score to measure improvement against

• Nocturnal and morning erections — men who still have them typically have intact vascular and nerve function, pointing toward a psychological or medication-related cause

• Medical and medication history, including cardiovascular risk factors

• Physical examination, including genital exam to check for Peyronie’s plaque, testicular size, and signs of hormone deficiency

• Blood tests — morning total testosterone (ideally confirmed on a second morning sample if low), fasting glucose or A1c, lipid panel, and thyroid function where indicated

• Blood pressure and cardiovascular risk assessment

• Penile Doppler ultrasound — reserved for younger men, men with a history of pelvic trauma, or cases where the cause remains unclear or surgery is being considered

What are the treatment options for erectile dysfunction?

Treatment escalates in steps. Most men respond at the first or second, and the great majority find an option that works.

1. Lifestyle changes and treating the underlying cause

Not a token first step — this is the only category that addresses the disease rather than the symptom. Regular aerobic exercise, weight loss, smoking cessation, reducing alcohol, improving sleep, treating sleep apnea, and controlling diabetes, blood pressure, and cholesterol all measurably improve erectile function. Reviewing and substituting contributing medications frequently resolves the problem outright.

2. Oral medications (PDE5 inhibitors)

Sildenafil (Viagra®), tadalafil (Cialis®), vardenafil (Levitra®), and avanafil (Stendra®) improve blood flow to the penis. All four are effective; they differ mainly in onset, duration, and food interaction. Tadalafil lasts substantially longer and can be taken as a low daily dose, which suits men who prefer not to plan around timing — and which also treats urinary symptoms from an enlarged prostate at the same time.

These medications require sexual stimulation to work. They do not produce an erection on their own, and men who expect otherwise sometimes conclude the drug failed when it was simply used incorrectly. Adequate trials at an adequate dose matter — a meaningful proportion of "treatment failures" are men who tried one dose once.

⚠️ Important safety information: PDE5 inhibitors must never be combined with nitrate medications — including nitroglycerin, isosorbide, and amyl nitrite ("poppers"). The combination can cause a severe, potentially fatal drop in blood pressure. Tell your physician about every medication you take, including recreational substances. Caution is also required with alpha blockers and in men with significant cardiovascular disease, which is another reason ED warrants a proper evaluation rather than an online purchase.

3. Vacuum erection devices

A cylinder and pump draw blood into the penis, with a constriction ring maintaining the erection. Non-invasive, drug-free, and reusable. Less spontaneous than medication, but effective, safe alongside other conditions, and particularly valuable in penile rehabilitation after prostate surgery.

4. Injection and intraurethral therapy

Intracavernosal injection of alprostadil, alone or in combination formulations, produces an erection directly and works even when pills do not — including for many men after prostate surgery. Response rates are high. It requires instruction and an in-office test dose, and most men find it far less daunting in practice than in prospect.

Intraurethral alprostadil is a small suppository placed in the urethra. Less effective than injection but avoids needles.

5. Testosterone therapy — when it is genuinely indicated

Testosterone therapy is appropriate for men with confirmed low testosterone on morning testing plus symptoms, not for ED alone. Testosterone more often restores desire than erectile function itself, and many men on testosterone still need a PDE5 inhibitor.

Two things to know before starting:

Fertility. Testosterone therapy suppresses sperm production and can cause infertility, sometimes persistently. If you may want children, discuss alternatives — clomiphene or hCG — before starting.

Prostate considerations. This area has shifted substantially. The historical assumption that testosterone causes prostate cancer has not held up: the TRAVERSE trial, involving over 5,000 men, found no significant increase in prostate cancer incidence, and in June 2026 federal regulators requested labeling revisions narrowing the prostate cancer contraindication and removing the age-related hypogonadism limitation of use. Guidelines now support cautious use in selected men who are disease-free after treatment for low-risk prostate cancer, with monitoring.

That said, this is a decision to make with a urologist rather than a telehealth questionnaire. Baseline PSA and prostate assessment before starting, and PSA monitoring during treatment, remain standard. Active or suspected untreated prostate cancer remains a contraindication.

6. Penile implants

For men who do not respond to, or cannot use, other treatments, a penile prosthesis is a definitive solution — and among the highest-satisfaction procedures in all of urology, for patients and partners alike.

Inflatable implants are the most commonly used type in the United States. Three-piece devices — two cylinders in the penis, a pump in the scrotum, and a fluid reservoir placed internally — provide the most natural rigidity and the most natural flaccid appearance. Two-piece devices combine the reservoir into the pump, simplifying the operation, which suits some men on anticoagulants or with prior abdominal surgery.

Malleable (semi-rigid) implants are bendable rods positioned by hand. Simpler, with no mechanical parts to fail, and easier for men with limited dexterity, though the penis remains permanently firm.

Implants are permanent: the procedure removes erectile tissue, so other treatments will no longer work afterward. Devices are mechanical and may eventually need revision. Modern implants are durable and infection rates are low, but this is a considered decision, not a first-line one.

What about shockwave therapy and PRP?

These are heavily marketed, and men ask about them constantly, so here is a straight answer.

Low-intensity shockwave therapy is considered investigational by the American Urological Association. A 2025 Cochrane systematic review of 21 randomized trials found it may produce a small short-term improvement in erectile function, but the certainty of that evidence was rated low and the clinical importance uncertain. European guidance is somewhat more permissive for mild ED or poor responders to pills, but with a weak recommendation. It is generally not covered by insurance.

Platelet-rich plasma (PRP) injections, marketed under various brand names, are considered experimental. There is no established evidence base supporting routine use.

Neither is inherently unreasonable to consider, but they should be presented as unproven rather than as established treatments — and any clinic charging substantial out-of-pocket fees while implying proven efficacy is worth approaching skeptically.

Why choose Dr. Samadi

• Board-certified urologist and fellowship-trained urologic oncologist

• Cause-first evaluation — including the cardiovascular and metabolic assessment that a new ED diagnosis warrants

• Particular experience with ED after prostate cancer treatment, including rehabilitation planning before and after surgery

• Honest counseling about unproven treatments, rather than upselling them

• Discreet Midtown Manhattan office at 485 Madison Avenue, convenient to Grand Central

We accept most major insurance plans; our team will verify your specific coverage before your visit.

Schedule a confidential consultation

ED is common, treatable, and worth evaluating properly — both to restore function and to check what it may be signaling about your overall health.

Request an Appointment

Office: 485 Madison Avenue, 21st Floor, New York, NY 10022 Phone: (212) 365-5000 Hours: [insert hours]

Sources

• Burnett AL, Nehra A, Breau RH, et al. Erectile Dysfunction: AUA Guideline. Journal of Urology.

• Salonia A, et al. EAU Guidelines on Male Sexual and Reproductive Health, 2025 update. European Urology.

• Ergun O, et al. Low-intensity shockwave therapy for erectile dysfunction: Cochrane systematic review, 2025; abridged in BJU International, 2026.

• Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE). New England Journal of Medicine, 2023.

• U.S. Department of Health and Human Services / FDA. Requested updates to testosterone therapy product labeling, June 2026.

• Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline.

This page provides general medical information and is not a substitute for individualized medical advice. Discuss your symptoms and treatment options with a qualified physician.