Erectile Dysfunction: Causes, Investigation & Treatment

When you come to see me about your erections, they become my second priority. My first is making sure you will be around long enough to enjoy them — for a long time.

Erectile dysfunction is a symptom. It has causes. Most of those causes are findable — and most are treatable. But there is something more important than finding a treatment: accepting ED as a normal part of ageing is not just wrong. It can be dangerous. The same vascular disease that causes erection problems can be silently affecting your heart and arteries years before any cardiac symptoms appear. If you dismiss it, you may be closing a window on a diagnosis that, caught early, could prevent a cardiac event. This page maps the territory. The spoke pages go deeper on each topic.

What I am actually looking for

I have been doing this long enough to see the full range of what people bring into the consulting room. Three conversations have stayed with me.

The man who had decided he was done

He was 40. He had enjoyed a satisfying sex life, and he had made a calm, considered decision that that chapter was behind him. He wanted a health check, not a rescue. I respected that entirely. His erections were not the clinical question. His cardiovascular picture was — and we addressed that.

The man who could only manage once a day

He was 86. He was distressed because he felt his sexual function was declining — he could only achieve an erection once a day, where previously he had managed more. I respected his expectation too. I also gently helped him understand what is realistic at different stages of life. We talked about what his body was telling him, and what it was not.

The couple who had lost count

They came together, and there was real fear in the room. He had noticed that his ejaculatory frequency had dropped from six or seven times in a row to three. They had interpreted this as a sign that something was seriously wrong. It was not. We talked about what normal variation looks like across a relationship, and what would genuinely need investigating.

I respect every baseline. But respecting your expectations is not the same as accepting all of them as realistic — and more importantly, it is not the same as deciding that nothing needs looking at.

My question is never: is this normal for your age? My question is: is this telling me something I should not miss? Those are two completely different conversations. The first one is about your preferences. The second one might be about your heart.

Something I notice consistently in clinic: patients tell me things they have never told their GP. Not because they were hiding it — when I ask whether I can share the full picture with their GP, the answer is almost always yes. The problem was not that they did not want their GP to know. The problem was that nobody asked. Sexual health sits in a particular silence in primary care — not from malice, but because the system rarely creates the space. I ask. Directly. And people answer.

Sex is one of the most intimate things a person can share with a clinician. I consider it a privilege to be trusted with it. Whether it involves one person or several, in one configuration or many — my questions are clinical, not moral. I have never sat in judgement of a patient's sexuality. Not because I am trying to be open-minded. Because it genuinely does not occur to me.

If something here does not reflect your experience, or you feel the information could be better — I would welcome that feedback. This page is reviewed regularly and improved with patient input.

What is actually happening

An erection is a vascular event. Sexual arousal triggers nerve signals that release nitric oxide in the erectile tissue of the penis. This relaxes smooth muscle, increases arterial inflow, and as the erectile chambers fill with blood, they compress the outflow veins — trapping blood inside at high pressure. The result is rigidity.

When that process fails, it usually fails at one of two points: the inflow (arterial insufficiency) or the trapping mechanism (venous leak). But the mechanism that triggers it — and the mechanism that can override it — is neurological and psychological. Adrenaline, released in response to stress or anxiety, directly constricts the penile arteries and prevents the process from starting.

This is why the old question — is it physical or is it in your head? — is the wrong question. For most people, it is both. Mixed aetiology is the clinical norm, not the exception.

Vascular and structural. Atherosclerosis, high blood pressure, diabetes, and smoking all damage the endothelial lining of blood vessels, reducing nitric oxide production and restricting arterial inflow. Venous leak — where blood drains out of the penis too quickly — is a separate but related structural problem. These causes tend to develop gradually and affect erections in all contexts.

Neurological. Nerve damage from diabetes, pelvic surgery, spinal cord injury, or neurological conditions can interrupt the signals required to initiate an erection. Medications — particularly antidepressants, antihypertensives, and opioids — can affect the same pathways.

Psychogenic and relational. Stress, performance anxiety, depression, and relationship dynamics can activate the sympathetic nervous system — the adrenaline response — which physically prevents erection regardless of physical capacity. This mechanism is real, measurable, and often the dominant driver in younger men.

How do I know what is causing mine

The pattern of your symptoms tells me most of what I need to know before any test is ordered. I am looking for variability — and where that variability falls.

A brief self-assessment can help calibrate how significant the difficulty is and give us a shared starting point for our conversation.

Erectile dysfunction tests — what the investigation involves

For a full breakdown of what the investigation involves — blood tests, hormone panels, and the tests most workups miss.

Is this telling me something about my heart

The penile arteries are 1 to 2 millimetres in diameter. The coronary arteries that supply the heart are 3 to 4 millimetres. Atherosclerosis — the narrowing and hardening of arteries — affects the smaller vessels first. This means that erectile dysfunction caused by vascular disease typically appears two to five years before cardiac symptoms develop.

An erection is a vascular event. And vascular events do not happen in isolation.

The basic workup every new ED presentation should trigger

Before any treatment decision, a proper first assessment includes: blood pressure measurement, fasting blood glucose or HbA1c, a lipid profile, and a morning testosterone level. If your GP has not offered this, it is reasonable to ask. If you are coming to see me directly, I will organise it from the start.

The Princeton IV Consensus (2024) formally designates erectile dysfunction as a cardiovascular risk-enhancing factor — comparable in significance to a family history of premature heart disease. This is not a reason to panic. It is a reason to look at your cardiovascular picture properly, and not as an afterthought.

ED and cardiovascular disease

Why erectile dysfunction is often the first sign of systemic vascular disease — and what that means for your health.

It works alone but not with a partner

This is the most common pattern I see in clinic. The erection works reliably when you are alone, fails with someone who matters. The nervous system responds to how much the moment matters — and the more someone matters, the higher the stakes feel.

There is an entire spoke page on this, because it deserves more than a paragraph.

Can't get hard with a partner?

Why this happens, why it happens more with someone you care about, and what actually helps — including a note for partners.

What are the treatment options

Treatment depends on the cause — which is why a proper assessment comes first. The options below follow the standard clinical hierarchy, from least to most invasive.

Treatment tiers

First line: lifestyle and oral medication

Cardiovascular risk factor management, exercise, and PDE5 inhibitors (sildenafil, tadalafil, vardenafil, avanafil). Effective for 60 to 80% of men when used correctly. Require sexual arousal to work. Not addictive.

Second line: injection therapy and vacuum devices

Intracavernosal injection of alprostadil — a small, self-administered injection that produces a reliable erection within 10 to 15 minutes. Success rate over 85%. Vacuum erection devices are a non-pharmacological alternative suitable for most men.

Shockwave therapy

Low-intensity extracorporeal shockwave therapy (LI-SWT) can be offered for mild to moderate vasculogenic ED according to EAU 2026 guidelines. The AUA (USA) still classifies it as investigational. It is a reasonable option for selected patients — not a universal solution.

Third line: penile implant

Surgical placement of an inflatable or semi-rigid prosthesis. Reserved for men who have not responded to other options, or who prefer a permanent solution. Patient satisfaction is high — the majority of men who have the procedure are glad they did.

PDE5 inhibitors. These work by enhancing the nitric oxide pathway, making it easier to achieve and maintain an erection when you are aroused. They do not cause erections without stimulation. One failed attempt is not a reliable test — it typically takes four to eight properly-conducted attempts to determine whether a medication is working for you. They are not harmful to the heart for most men; the contraindication with nitrate medications is a pharmacological interaction, not evidence of cardiac toxicity. A patient leaflet explaining how to use them is available below.

Injection therapy (ICI). The needle is fine, the technique is straightforward, and I teach it in clinic with a supervised first injection. Most men who start ICI continue it long-term. A complete guide is available below.

Shockwave therapy. I offer this for selected patients with vasculogenic ED as part of a broader treatment plan. I am transparent about the evidence base: the EAU 2026 guidelines support it for mild to moderate cases; the AUA is more cautious. I would not recommend it as a standalone treatment for significant vascular disease.

Venous surgery. Surgical repair of venous leak is not recommended by current EAU or AUA guidelines due to poor long-term outcomes. If you have been told you need venous surgery, I would encourage a second opinion.

Penile implant. This is a considered decision, not a rushed one. It is the right answer for a specific group of men — those who have tried other options, or who have structural disease severe enough that other options will not work. When it is appropriate, it resolves the problem definitively.

Treatment resources

Patient leaflets for PDE5 inhibitors and injection therapy are available to download. They cover how each treatment works, how to use it correctly, and what to watch for.

What about testosterone

Testosterone deficiency rarely acts alone as the cause of erectile dysfunction. Its primary role is in sexual desire — and it does contribute to the health of erectile tissue and the NO pathway, so low levels are worth correcting when present. But if your testosterone is normal, replacing it will not fix your erection.

The important caveat is that testosterone deficiency frequently coexists with ED from other causes. In men with diabetes, metabolic syndrome, or significant weight gain, testosterone may be suppressed, and addressing it is part of a complete cardiometabolic picture.

Testosterone varies significantly across the day and is affected by acute illness, sleep deprivation, and stress. A reliable sample requires a fasting morning blood test, taken between 07:00 and 11:00. A single low result is not sufficient for a diagnosis — it needs to be confirmed on a second occasion, at least four weeks later. If you have had your testosterone checked at a random time of day and told it is low, the result may need repeating under proper conditions before any treatment is considered.

Testosterone deficiency and TRT

How testosterone deficiency is diagnosed properly, what treatment involves, and the fertility implications.

What you may have been told — and what the evidence shows

Myth vs Fact

Fact

Fact: Sexual health is one of the most under-explored areas in primary care — not because GPs do not care, but because the consultation culture rarely creates the space. Most of my patients have never been asked about their erections by their GP. The conversation did not happen because nobody started it. That does not mean nothing was worth discussing.

Fact

Fact: Erectile dysfunction is not an inevitable consequence of ageing. It has causes — most of them findable. More importantly, the vascular disease that causes ED often precedes cardiac symptoms by two to five years. Dismissing it as normal ageing does not just delay treatment for ED. It may delay a diagnosis that could prevent a heart attack.

Fact

Fact: Any new presentation of erectile dysfunction warrants a basic workup: history, examination, HbA1c, lipid profile, morning testosterone. Anxiety as a diagnosis does not rule out vascular, hormonal, or medication-related contributors. It is not a reason to skip the investigation — it is a reason to look at all the drivers together.

Fact

Fact: PDE5 inhibitors enhance the physiological response to arousal — they do not repair vascular disease, correct a hormone deficiency, or resolve a relationship dynamic that is not working. They are a useful tool in the right context. They are not a substitute for understanding what is actually happening.

Fact

Fact: Morning erections suggest that your neurovascular pathways are at least partially intact. They do not exclude mixed aetiology, organic contributors, or the need for a proper assessment. They are one data point, not a complete picture.

The Man Who Was Told It Was Stress

He was 47. He had been having progressive erection difficulties for just over two years. His GP had been thorough in some ways — he had been told to reduce stress, improve sleep, cut back on alcohol. What had not happened was any blood test.

When he came to see me, I took a full history and ran a basic panel. His HbA1c came back at 46 — technically pre-diabetic, but meaningfully elevated. His lipid profile showed a pattern consistent with early metabolic syndrome. His morning testosterone was in the low-normal range.

I did not order a Doppler scan. There was no indication for one at that stage.

The plan was straightforward: lifestyle changes with specific cardiometabolic targets, a short course of a PDE5 inhibitor as scaffolding while he rebuilt confidence, and a letter back to his GP recommending they take ownership of the metabolic picture — which they did.

At three months his erection function had improved significantly. More importantly, his glucose and lipids were now under active management. His GP told him it was the first time they had seen results that made them think about cardiovascular risk in a 47-year-old.

The diagnosis was not erectile dysfunction. It was metabolic syndrome expressing itself through erectile function first. The erection brought him into a clinical conversation that his heart needed him to have.

How severe is your difficulty — a quick self-assessment

What happens next — the diagnostic workup

Once you have a sense of severity, the next step is understanding what is driving it. See what the investigation involves.

In men over 40, vascular disease is the most common underlying contributor — atherosclerosis reducing arterial inflow, or veno-occlusive dysfunction affecting the trapping mechanism. In younger men, psychogenic factors and performance anxiety are more frequently the primary driver, though physical contributors including medication side effects, diabetes, and testosterone deficiency should always be excluded. Mixed aetiology — where both physical and psychological factors are present — is the norm rather than the exception at any age.

Yes — and this is one of the most important things to understand about ED. The penile arteries are significantly smaller than the coronary arteries, which means they tend to show the effects of vascular disease earlier. Studies consistently find that ED precedes major cardiac events by two to five years on average. The Princeton IV Consensus (2024) formally classifies ED as a cardiovascular risk-enhancing factor. This is not a reason for alarm — it is a reason to use an ED presentation as an opportunity to review cardiovascular risk properly, including blood pressure, glucose, and lipids.

It depends on the cause. Psychogenic ED, medication-induced ED, and ED driven by reversible lifestyle factors — obesity, alcohol, sedentary behaviour — often improves significantly or resolves with appropriate intervention. Vascular disease is not reversible in the structural sense, but its progression can be slowed and its effects managed effectively. For men with significant structural vascular damage, treatment options including injection therapy and penile implants provide reliable solutions even when the underlying physiology cannot be fully restored.

Both are PDE5 inhibitors and work by the same mechanism. The main practical difference is duration: sildenafil (Viagra) is active for approximately four to five hours and should be taken 30 to 60 minutes before activity, ideally not with a heavy meal. Tadalafil (Cialis) remains active for up to 36 hours, which removes the need to time the dose precisely, and is also available as a low daily dose (2.5 to 5 mg) for a continuous background effect. Neither drug causes erections without sexual stimulation. The choice between them usually comes down to lifestyle preference and individual response.

Losing an erection during penetration or shortly after is one of the most common presentations. The causes range from vascular — where inflow is adequate but the trapping mechanism is insufficient, allowing blood to drain out too quickly — to psychological, where the activation of the sympathetic nervous system (the adrenaline response) interrupts the process at the point of highest pressure. Distinguishing between these requires a proper history and, in some cases, a penile Doppler ultrasound. A common and treatable pattern.

If your GP has offered a thorough assessment — full history, basic blood tests including testosterone, glucose and lipids, blood pressure, and a clear management plan — a specialist may not be immediately necessary. If you have been told "it's stress" or given a prescription without any investigation, it is reasonable to want a more structured assessment. A specialist consultation is also appropriate if first-line treatment has not worked, if there is a specific concern about the vascular picture, or if you want a penile Doppler to characterise the blood flow pattern properly. You do not need a GP referral to see me — self-referral is straightforward.

An enlarged prostate (BPH) does not directly cause ED through mechanical means. However, the two conditions share common risk factors and often coexist — particularly in men over 50. More relevant is the effect of BPH treatments: certain medications (particularly 5-alpha-reductase inhibitors such as finasteride and dutasteride) can affect libido and erections in a minority of men. If your ED started or worsened after starting treatment for prostate symptoms, that connection is worth discussing.

Before anything else — a piece of advice

Sex is not a performance. It is an interaction — and at its most fundamental, a form of communication between two people. The moment it becomes a test with measurable outcomes, it stops being either of those things.

Before any investigation, any medication, any referral — the single most useful thing is usually a conversation with your partner. Not in bed. Not in a moment of crisis. A calm conversation, at a point when neither of you is under pressure, about what you are each experiencing and what you each need.

There is no formula for this, because you are not a formula. What I can tell you is that every couple I see who navigates this well has found a way to talk about it. Not necessarily easily. But honestly.

A guide for partners

Including a note on the three most common reactions — and why the most instinctive ones are rarely the most useful.

Can't get hard with a partner?

Partner-specific erection difficulties — the most common presentation and the most under-discussed.

Venous leak — symptoms, diagnosis and treatment

When the problem is structural. How penile Doppler ultrasound maps the vascular picture and what the options are.

Penile Doppler ultrasound — the investigation explained

What the test involves, how to interpret results, and when it is and is not indicated.

Peyronie's disease

Penile curvature, scar tissue, and the body image spiral — including treatment options and when surgery is appropriate.

Testosterone deficiency and TRT

When low testosterone contributes to ED, how to diagnose it properly, and what treatment involves.

Shockwave therapy for ED

What the evidence says, who it is suitable for, and what to expect from a course of treatment.

Premature ejaculation

A separate but frequently co-occurring condition — causes, classification, and treatment options.

Erectile dysfunction tests — the complete assessment guide

What blood tests, hormone panels and specialist investigations are needed — and the tests most workups miss.

Ready to understand what is actually happening?

A single consultation is enough to map the pattern, identify what needs investigating, and give you a clear clinical picture. You will not be handed a prescription and shown the door.

Book a consultation

Your Health is Our Priority

Erectile Dysfunction — Causes, Investigation and Treatment

What I am actually looking for

What is actually happening

How do I know what is causing mine

Is this telling me something about my heart

It works alone but not with a partner

What are the treatment options

What about testosterone

What you may have been told — and what the evidence shows

How severe is your difficulty — a quick self-assessment

Before anything else — a piece of advice

Related guides

Evidence & Medical Sources13 Sources

EAU Guidelines on Sexual and Reproductive Health 2026

A practical guide on managing erectile dysfunction (based on 2017 BSSM guidelines), version 3

PIF TICK accredited information

Erectile Dysfunction: AUA Guideline

Erectile Dysfunction as an ASCVD Risk-Enhancing Factor: Highlights From the Princeton IV Consensus Guidelines

Development and evaluation of an abridged, 5-item version of the International Index of Erectile Function (IIEF-5) as a diagnostic tool for erectile dysfunction

ED as predictor of cardiovascular events

Moral incongruence and pornography use

Is pornography use related to erectile functioning? Results from cross-sectional and latent growth curve analyses

Low-intensity extracorporeal shockwave treatment improves erectile function: a systematic review and meta-analysis

Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study

Nagoski E — Come As You Are (revised 2021)

Nagoski E — Come Together (2024)

Gurney K — Mind The Gap (2020)