Erectile dysfunction (ED) is the persistent inability to get or maintain an erection sufficient for satisfactory sex. It is common — prevalence increases with age, and estimates suggest a substantial proportion of men over 40 experience it at some point. It is also treatable in the majority of cases. The important shift in modern UK practice is that ED is no longer treated as a purely urological or sexual problem: it is often the first visible sign of something happening in the vascular system, and a proper review looks at the whole picture.

This article walks through what ED actually is, the common causes, when to see a clinician, and what treatment tends to look like in the UK — including where PDE5 inhibitors such as sildenafil (Viagra) and tadalafil (Cialis) fit in.

What counts as erectile dysfunction

An occasional difficulty getting or keeping an erection is not clinical ED. Stress, poor sleep, alcohol and tiredness can all produce isolated episodes and are not, on their own, a diagnosis. Clinicians typically use the label when the difficulty has been present most of the time for at least three months and is affecting the person's quality of life or relationships. That framing matters because it separates a transient issue from something that warrants a proper workup.

Erections are a coordinated event — arterial blood flow, venous trapping, nerve signalling and psychological arousal all have to line up. Because so many systems are involved, ED tends to be multifactorial. That is why the same conversation with a clinician often ends up covering blood pressure, sleep, stress and medication history alongside the sexual symptoms themselves.

The arteries that supply the penis are narrower than those supplying the heart or brain. This means that atherosclerosis — the gradual narrowing of blood vessels — can show up as ED before it shows up as chest pain or a stroke. Longstanding, gradual-onset ED without an obvious psychological trigger is a recognised reason to have blood pressure, cholesterol, glucose and lifestyle risk factors reviewed. This is now standard practice in UK men's health.

Common vascular contributors include untreated or under-treated hypertension, diabetes, high cholesterol, smoking, obesity and physical inactivity. None of these need to be severe to affect erectile function. Managing them well often improves ED alongside cardiovascular risk more broadly, and is one reason clinicians rarely treat ED in isolation.

Hormonal causes

Low testosterone (hypogonadism) can contribute to reduced libido and, in some men, to ED — but it is not the leading cause. In UK practice, hypogonadism is diagnosed by symptoms plus two morning blood tests showing low total testosterone on separate days. A single number is not sufficient, and testosterone replacement is not appropriate for men whose bloods are normal. Thyroid disease and rarely elevated prolactin can also contribute and are usually screened for when the picture warrants it.

Neurological and pelvic causes

Any condition affecting nerve signalling to the pelvic region can affect erections. Diabetes is the most common example because long-term high blood sugar damages small nerves. Multiple sclerosis, spinal cord injury, previous pelvic surgery (notably prostate surgery) and radiotherapy can all contribute. These causes usually have other clues in the history, and a clinician will ask about them explicitly.

Medication side effects

A number of commonly prescribed medications can contribute to ED. These include some blood pressure medicines (particularly older beta-blockers and thiazide diuretics), certain antidepressants (especially SSRIs), some antipsychotics, opioids and 5-alpha reductase inhibitors. The right response is not to stop these medications on your own — it is to raise it with your clinician, who may be able to adjust the dose or switch to an alternative. Your clinician will advise based on your individual circumstances.

Psychological factors

Performance anxiety, relationship stress, low mood and depression are all recognised contributors. Younger men presenting with ED are more likely to have a significant psychological component, and older men often have a mix of psychological and physical drivers. Sudden-onset ED that occurs only in some situations (for example, with a partner but not on waking or during masturbation) suggests a psychological component that may respond to talking therapy, sex therapy or CBT.

When to see a clinician

Any persistent difficulty lasting more than a few weeks is worth reviewing. It is particularly important to seek advice if ED is progressive, if it started suddenly with no obvious trigger, if it is accompanied by chest pain, breathlessness or leg pain on walking, or if there are also symptoms of low testosterone such as persistent low libido and fatigue. Sudden-onset severe ED after a fall or spinal injury needs urgent review. The consultation is confidential and — in a well-run UK service — should feel practical rather than embarrassing.

At consultation, a clinician will typically ask about how long the problem has been present, what it looks like in different situations, morning erections, libido, mood, sleep, alcohol, recreational drug use, medications and cardiovascular history. Blood pressure is usually checked, and blood tests may be arranged for glucose, lipids and, in some cases, testosterone.

First-line treatment — PDE5 inhibitors

PDE5 inhibitors are the first-line pharmacological treatment for ED in the UK for most men, where safe to use. Sildenafil (the active ingredient in Viagra) is the shorter-acting option and is typically taken 30 to 60 minutes before sex. Tadalafil (the active ingredient in Cialis) has a longer window of activity, up to around 36 hours after a dose, which some men find more compatible with a spontaneous sex life. Both require sexual stimulation to produce an erection — they do not cause an erection on their own.

These medicines work by enhancing the blood flow response that normally happens during sexual arousal. Common side effects include headache, flushing, indigestion and nasal congestion. Rare but important interactions include nitrates (used for angina) and nicorandil, which must not be combined with PDE5 inhibitors because of the risk of a serious drop in blood pressure. This is why a proper consultation, with your full medication list, matters. Over-the-counter Viagra Connect exists for some men, but a pharmacist-led check is still required.

Other treatment options

Where oral therapy is not suitable or not effective, other options exist. These include vacuum erection devices, intracavernosal injections, transurethral treatments and, in a small subset of cases, penile implants. Psychosexual therapy has good evidence when there is a psychological component and can be used alongside medication rather than instead of it. For more on how testosterone interacts with sexual and hair health, see our related article on low testosterone and hair loss.

Lifestyle factors that genuinely help

Because ED shares its risk factors with cardiovascular disease, the same lifestyle changes tend to help both. Regular aerobic exercise, weight loss where relevant, stopping smoking, moderating alcohol and improving sleep quality all have evidence in improving erectile function over months. They are not a substitute for treatment where treatment is warranted, but they meaningfully change the trajectory. For men whose weight is a major factor, our overview of GLP-1 receptor agonists may be relevant background reading.

Working with a Farmeci clinician

A Farmeci consultation for ED covers the same ground as an in-person GP appointment: symptom pattern, timeline, medications, cardiovascular risk and lifestyle. If a PDE5 inhibitor is appropriate, the clinician will discuss which one, at what starting dose, and how to assess response over the first few attempts. If your history suggests a wider workup is needed — for example, uncontrolled blood pressure or possible hypogonadism — that will be flagged and referred back into NHS care where appropriate. ED is one of the most treatable men's health issues, but it deserves a proper clinical review, not a guess.