Erectile Dysfunction

What erectile dysfunction is

Both major guidelines define erectile dysfunction as a persistent problem rather than an occasional one, and neither treats a single bad night as anything. The American Urological Association describes it as "an impairment in the arousal phase of sexual response" and defines it as "the consistent or recurrent inability to attain and/or maintain penile erection sufficient for sexual satisfaction, including satisfactory sexual performance". The European Association of Urology defines it as "the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance". Those two sentences are not the same sentence, and the difference is set out in the disagreements section below.

The mechanism behind most of it is vascular. An erection is a haemodynamic event, and the arteries that supply the penis are small — which is why they narrow earlier, and symptomatically, in a process that is also narrowing larger arteries silently elsewhere. The AUA puts it as "Compelling evidence exists that the most common underlying mechanism of ED is vascular and that CVD and ED share etiologies as well as pathophysiology." That is the whole reason this is a condition page and not a product page.

It is also commonly multifactorial, and the European guideline warns against the neat organic-versus-psychogenic split for exactly that reason: "this classification should be used with caution as most cases are of mixed aetiology". A man in his fifties with untreated hypertension, a stressful year and a new beta-blocker does not have one cause. He has three, and any consultation that finds the first and stops has not finished.

One distinction is worth getting right before anything else, because the guidelines say men routinely get it wrong. Erectile dysfunction is not low sexual desire, it is not premature ejaculation, and it is not the refractory period lengthening with age. The AUA is explicit that men "may confuse changes in sexual desire, orgasm/refractory period, ejaculatory function (i.e., premature or rapid ejaculation), and conditions such as Peyronie’s Disease (PD) with ED", and that low desire matters to establish early because "successful ED treatment will not address this issue".

Why a score is not an answer

Unlike most conditions on this site, erectile dysfunction has validated instruments that both guideline bodies endorse. The Sexual Health Inventory for Men is five questions scored 1 to 5. The full International Index of Erectile Function is fifteen questions across five domains, of which the erectile-function domain is scored 5 to 30. Both are published, both have interpretation bands, and both bands are printed in the second table on this page.

What they measure is severity. The AUA describes their purpose precisely: they "quantify ED severity and the consequences of ED (e.g., bother, sexual satisfaction, relationship impact)" and are "useful to measure treatment effectiveness and to adjust management plans based on outcomes over time". Every one of those uses assumes a man who has already been evaluated and is now being followed. None of them is a diagnostic test, and neither guideline claims otherwise.

The history that actually discriminates is the one no questionnaire captures. The AUA lists what it consists of: onset, whether the problem is attaining or maintaining, whether it happens in every context or only some, whether nocturnal and morning erections are still present, whether symptoms are stable or progressive. That last one carries a warning: "worsening symptoms may suggest the presence of progressive underlying comorbidities, particularly cardiovascular comorbidities, that need to be definitively addressed." A score does not have a direction of travel in it.

And the examination finds things the questionnaire cannot. The AUA describes palpating the penis stretched from the pubic bone to the coronal sulcus for plaque, examining the scrotum for testicular size and consistency, and looking for the signs of testosterone deficiency — it names gynecomastia and under-developed facial, pubic or axillary hair. Those are the structured signs at the foot of this section. They are there because a man cannot do any of them to himself.

The signs that are specific — and none of them are self-assessable

A palpable penile plaque

Found by holding the penis stretched and palpating from the pubic bone to the coronal sulcus. The AUA is careful about what it means: the presence or absence of a palpable plaque "should not be taken as definitive evidence for clinically relevant penile deformity", and suspected Peyronie’s disease needs its own diagnostic pathway.

An absent bulbocavernosus reflex

Assessed during a digital rectal examination, and informative about the neural integrity of the pelvis. It is also the clearest example on this page of why a single finding is not a diagnosis: the AUA records that this reflex is absent in up to 30% of normal patients, so its absence alone means very little.

Signs of testosterone deficiency on examination

The AUA names gynecomastia and under-developed facial, pubic or axillary hair as the examination findings that point towards testosterone deficiency in a man presenting with erectile dysfunction. Both are observations a clinician makes and neither is a symptom you report; testosterone deficiency is then a separate diagnosis with its own criteria.

Abnormal cavernosal haemodynamics on dynamic duplex ultrasound

A second-line test the EAU reserves for suspected vascular causes. It gives measured numbers — the guideline records peak systolic blood flow above 30 cm/s, end-diastolic velocity below 3 cm/s and a resistance index above 0.8 as usually considered normal — and it requires an intracavernosal injection and an operator.

The diagnostic criteria, quoted

Each criterion below is the guideline’s own wording, not a summary of it. Our reading follows underneath, so you can weigh one against the other.

1. Persistent, not occasional — and the two bodies word it differently

   “Erectile dysfunction (ED) can be conceptualized as an impairment in the arousal phase of sexual response and is defined as the consistent or recurrent inability to attain and/or maintain penile erection sufficient for sexual satisfaction, including satisfactory sexual performance.”

   Two words are doing the work. "Consistent or recurrent" excludes a bad week. "And/or" means that losing an erection you were able to get counts, which is the commonest presentation there is. Hold that against the European wording quoted below, which says "attain and maintain" — read literally, that is a narrower door. Neither body sets a frequency threshold, a duration or a number of failed attempts, and this page does not supply one.

2. The European definition, for comparison

   “Erectile dysfunction is defined as the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance”

   Same condition, different sentence. "Persistent" is a stricter word than "consistent or recurrent", and the conjunction differs. In practice both bodies then run essentially the same evaluation, which tells you the definitional gap is not what decides care — but it does mean that a definition you are quoted in a consultation may not be the one a different specialty would use, and neither is a test you can apply to yourself on a given evening.

3. It is a symptom, and the evaluation exists to find what it is a symptom of

   “Erectile dysfunction is a symptom, not a disease. Some patients may not be properly evaluated or receive treatment for an underlying disease or condition that may be causing ED.”

   This is the sentence to bring to any consultation that offers a prescription before it takes a history. Note the evidence level the EAU attaches: 4, meaning expert opinion. The panel is not claiming a trial proves it. It is stating the structure of the problem, and the structure is what makes the rest of the work-up mandatory rather than optional.

4. The minimum evaluation: history, examination, selected bloods

   “Men presenting with symptoms of ED should undergo a thorough medical, sexual, and psychosocial history; a physical examination; and selective laboratory testing.”

   Three components, and the third is qualified rather than open-ended. The AUA says that "With the possible exception of serum testosterone, glucose/hemoglobin A1c, and in some cases serum lipids, no routine serum study is likely to alter ED management" — so this is a short list, not a panel. What it is not is zero, and an online consultation that collects a questionnaire and a card number has performed none of the three.

5. Every man with erectile dysfunction gets a morning testosterone

   “For men with ED, morning serum total testosterone levels should be measured.”

   Unconditional in both guidelines, and it is the single test most often skipped. The AUA sets out what it would take to act on the result: "At least two morning serum total testosterone measures should be obtained before making the diagnosis of TD. If the values are similar and <300 ng/dL, then the man may be diagnosed with TD." One low afternoon reading is not that. Testosterone deficiency is a separate diagnosis with its own page, and the AUA notes the diurnal swing that makes timing matter — late afternoon levels "can be approximately 20% lower than morning values in young men, but the difference may be as high as 50%".

6. And a cardiovascular conversation, as a recommendation rather than a courtesy

   “Men should be counseled that ED is a risk marker for underlying cardiovascular disease (CVD) and other health conditions that may warrant evaluation and treatment.”

   The AUA adds who else should hear it: the clinician "should communicate this increased risk to the man with ED, to his partner, and to other relevant clinicians (e.g., the primary care provider)". Note the precision of the term. A risk marker is defined in the same paragraph as an attribute that predicts a disease without being part of the causal pathway — so this is a reason to be investigated, and it is not evidence that fixing the erection fixes anything upstream.

Where the guidelines disagree

On these points there is no consensus to report. Both positions are printed with the wording each body used.

The basic work-up, as each body specifies it

What the American and European guidelines ask for before anyone treats erectile dysfunction, and the strength each attaches. They ask for nearly the same things and grade them differently, which is the useful part.

Read the questionnaire row against the third table below. The same American body that grades a questionnaire as Expert Opinion here recommends against using validated questionnaires at all in its testosterone deficiency guideline. That is not an inconsistency: an ED questionnaire measures how bad a symptom the man is already reporting is, while a testosterone questionnaire is being asked to detect a deficiency he cannot feel. It is worth understanding the difference before treating any score as a diagnosis. Sources: [1] [2]

The published severity bands, for both instruments the AUA names

Reproduced from the AUA guideline’s discussion of Guideline Statement 2. These are the bands, exactly as published. This page prints them and does not administer them — see the refusals below for why.

The AUA is explicit that these two are not the same instrument even though the SHIM is sometimes called the IIEF-5: it "uses five of the six questions that comprise the IIEF-EF subscale, but the interpretation of scoring ranges is different". Two further cautions come from the guideline itself. A questionnaire "will not generate a valid score for the man who is not sexually active". And a score is a severity grade, not an aetiology — nothing in either instrument distinguishes a vascular cause from a hormonal, neurological, drug-induced or psychogenic one, and it is the cause that decides what happens next. Sources: [1]

Erectile dysfunction as a cardiovascular risk marker — the published figures

Every quantity the AUA attaches to its third guideline statement, with what each one is a measurement of. This is the part of the page that matters most and the part a tablet-selling consultation skips.

The last row is the one that has moved. The AUA text is built on the Princeton III three-tier scheme. The EAU has since adopted Princeton IV, which asks for a 2019 ACC/AHA atherosclerotic cardiovascular disease risk score for all men being evaluated for predominantly vasculogenic ED, and a coronary artery calcium score for those in the borderline-to-intermediate band. Both are printed in the disagreements section rather than merged. Sources: [1]

Every prevalence figure we could source, and what each one is

This page gives no single percentage for how many men of your age have erectile dysfunction. Here is why: these are the published figures we could open, and none of them is that number.

The Massachusetts Male Aging Study is a good study and its 52% is a real figure — it is simply a figure about a particular group of men in a particular place at a particular time, measured with a self-administered sexual activity questionnaire. The reason it is quoted everywhere as though it were a current national statistic is that nothing more recent has replaced it in the popular summaries. The study’s own conclusion is worth more than its headline number: impotence "has multiple determinants, including some risk factors for vascular disease, and may be due partly to modifiable para-aging phenomena". Sources: [1] [4]

The tests, and what each one answers

Things that are not erectile dysfunction, and things that cause it

Two different lists are collapsed here on purpose, because a reader needs both. Some entries are conditions men mistake for erectile dysfunction and which a prescription will not touch. Others genuinely produce it, which means a low-grade score confirms nothing about the cause. The AUA notes that in three surveys of men with ED, depression was reported by 11% and premature ejaculation by roughly 30% to 60% of respondents — so the overlap is the normal case rather than the exception.

Low sexual desire, including hypoactive sexual desire disorder

A different problem with a different treatment, and the AUA says to establish it early for a blunt reason: "Information regarding reduced or absent libido is important to elicit given that successful ED treatment will not address this issue, and it may continue to generate frustration and anxiety for the man and his partner." A tablet that produces an erection in a man who does not want sex has solved nothing.

Premature or early ejaculation, and the lengthening refractory period

The AUA distinguishes both explicitly — early ejaculation "leading to subsequent loss of erection due to the resolution phase", and the refractory period, "an interval after ejaculation/orgasm in which the penis will not become erect and which tends to increase in duration as a man ages". Either can be experienced as losing an erection, and neither is erectile dysfunction.

Peyronie’s disease and other penile deformity

Named by the AUA among the conditions men confuse with erectile dysfunction, and found by a specific examination — the penis held stretched and palpated from the pubic bone to the coronal sulcus. It has its own guideline and its own treatments, and the AUA warns that a palpable plaque on its own is not definitive evidence of a clinically relevant deformity.

Depression, anxiety and relationship conflict

The AUA treats these as capable of being primary rather than secondary: psychological and psychosexual factors "may be primary or secondary contributors to ED", and men "may not appreciate that depression, anxiety, stress, and relationship conflicts can interfere with the physiological processes necessary for erectile function". This is also the branch on which the guideline recommends involving a mental health professional rather than escalating the drug.

Medication effect, including some cardiovascular drugs

The EAU notes that "a number of therapeutic agents for CVD have been shown to have a detrimental effect on EF, whereas newer drugs have exhibited a neutral or even beneficial effect". This is the entry with the best ratio of effort to result: a medication review costs one appointment, and if the cause is on the list the answer is a substitution rather than a second prescription.

Testosterone deficiency

A real cause and a separate diagnosis with its own criteria, which is why both guidelines require a morning testosterone in every man with ED. It cannot be inferred from the erectile symptom: the European Male Ageing Study found erectile dysfunction among the symptoms associated with testosterone level, but the diagnosis still needs two morning samples and signs on examination.

Lower urinary tract symptoms and benign prostatic hyperplasia

The AUA reports that LUTS or BPH are "reported in up to 72% of men with ED" and that the two "are independent risk factors for each other". This matters practically as well as diagnostically, because one licensed drug — tadalafil — carries indications for erectile dysfunction, for the signs and symptoms of BPH, and for both together.

Treatment for prostate cancer, and pelvic surgery generally

The EAU reports that 25–75% of men experience erectile dysfunction after radical prostatectomy and that unassisted recovery of erectile function "ranges between 20 and 25% in most studies", with the ProtecT randomised trial finding erections firm enough for intercourse in 30% of the monitoring arm, 27% after radiotherapy and 17% after surgery at six years. Where this is the cause, the history gives it away immediately and the management is different.

What treatment means here

Numbers this page will not give you

Each of these is a figure other pages state confidently. Each is omitted here because no source we could open supports one.

What percentage of men my age have erectile dysfunction?

No current age-specific figure is printed because we could not source one that survives reading. The AUA states that "Up to 30 million men in the United States and 150 million men worldwide are estimated to be affected by ED" — an estimate with a range and no method attached. The most-quoted percentage in the field comes from the Massachusetts Male Aging Study, which reported that "The combined prevalence of minimal, moderate and complete impotence was 52%" and that "The prevalence of complete impotence tripled from 5 to 15% between subject ages 40 and 70 years". That is a genuine figure, but it is from a community sample of men aged 40 to 70 near Boston, surveyed between 1987 and 1989, using a self-administered questionnaire — not a current national prevalence and not a figure about you.

Can I score myself and find out whether I have erectile dysfunction?

The published bands for both instruments are printed in the second table, and this page will not run them for you. A questionnaire grades severity and contains nothing that identifies a cause; the AUA also records that it "will not generate a valid score for the man who is not sexually active". Handing a man a number without the examination and the three blood tests that belong with it is the exact route by which a cardiovascular risk marker turns into a tablet purchase.

Will treating my erectile dysfunction lower my risk of a heart attack?

No source we opened says so, and the AUA’s own wording rules the claim out. A risk marker is defined there as one of the "attributes that predict increased probability of a disease state but are not part of the causal pathway". Treating the marker is not treating the pathway. What the guideline does say is that the diagnosis "provides a pivotal opportunity to discuss and address cardiovascular risk" — the opportunity is the benefit, and taking it means acting on blood pressure, glucose, lipids and smoking, not on the erection.

Which PDE5 inhibitor is strongest, and what dose of one equals a dose of another?

No equivalence has been published and this site refuses to invent one — our dose equivalence tool exists specifically to say that, and a test in the codebase prevents any function here converting one agent’s dose into another’s. The AUA also found that even within a single drug the dose-response differences "were extremely small, rarely statistically significant, and generally not clinically significant", while adverse-event rates rose with dose.

How long do I have to have the problem before it counts?

Neither guideline states a duration, a frequency or a number of failed attempts. The AUA says "consistent or recurrent" and the EAU says "persistent", and neither defines those words numerically. A threshold here would be invented, and it would be the kind of invention a man uses to talk himself out of an appointment.

Frequently asked questions

Is erectile dysfunction a sign of heart disease?

It is a recognised risk marker, which is a narrower claim than a sign and a stronger one than a coincidence. The AUA makes it Guideline Statement 3: men "should be counseled that ED is a risk marker for underlying cardiovascular disease (CVD) and other health conditions that may warrant evaluation and treatment". The figures it attaches: symptoms may precede a cardiovascular event by up to five years; in younger men the presence of ED predicts "a marked increase (up to 50 fold) in the risk of future cardiac events"; and the QRISK group added ED to its 10-year model as an independent factor worth a 25% increase in risk for the average middle-aged man. The AUA also defines what a risk marker is — an attribute that predicts a disease "but are not part of the causal pathway" — so this is a reason to be investigated, not evidence that treating the erection protects the heart.

What tests should I have before being given a prescription?

Three things at minimum, and both guidelines agree on all three. A thorough medical, sexual and psychosocial history. A physical examination — genital, scrotal, and looking for signs of testosterone deficiency. And selected bloods: a morning total testosterone in every man, plus a fasting glucose or HbA1c and a lipid profile if they have not been done in the last 12 months. Blood pressure and heart rate if not measured in the last three to six months, and BMI or waist circumference. That is the whole list, and the AUA is clear it is short: apart from testosterone, glucose or HbA1c, and sometimes lipids, "no routine serum study is likely to alter ED management".

What SHIM score means I have erectile dysfunction?

The published bands, as the AUA prints them, are: 22–25 no ED, 17–21 mild, 12–16 mild to moderate, 8–11 moderate, 5–7 severe. Two cautions come with them. The bands grade severity, not cause — nothing in the five questions separates a vascular cause from a hormonal, drug-induced or psychogenic one, and the cause is what decides the treatment. And the instrument "will not generate a valid score for the man who is not sexually active". The SHIM is also not identical to the IIEF erectile-function domain despite being called the IIEF-5: the AUA notes it uses five of six questions from that subscale "but the interpretation of scoring ranges is different", which is why this page prints both scales side by side.

Do I need my testosterone tested if I have erectile dysfunction?

Yes, and it is the test most often skipped. Both guidelines ask for an early-morning total testosterone in every man presenting with erectile dysfunction — the AUA as a Moderate Recommendation at Grade C, the EAU as Strong. Timing matters because the swing is large: the AUA reports that late afternoon levels "can be approximately 20% lower than morning values in young men, but the difference may be as high as 50%". And one result is not a diagnosis. The AUA requires at least two morning measurements before diagnosing testosterone deficiency, and defines that condition as a level below 300 ng/dL together with symptoms and signs.

Could my blood pressure medication be causing this?

It is one of the most rewarding things to check, and the answer is genuinely mixed rather than uniformly bad. The EAU notes that "a number of therapeutic agents for CVD have been shown to have a detrimental effect on EF, whereas newer drugs have exhibited a neutral or even beneficial effect". A medication review costs one appointment and can make a second prescription unnecessary. Never stop a cardiovascular drug to test the theory — the substitution is the clinician’s job, and the underlying condition is more dangerous than the side effect.

Is it psychological or physical?

Usually both, and the European guideline warns against forcing the choice: erectile dysfunction "is commonly classified into three groups based on aetiology: organic, psychogenic and mixed ED. However, this classification should be used with caution as most cases are of mixed aetiology." One history clue points towards a psychogenic component without settling it — the AUA notes that the presence of nocturnal or morning erections "suggests (but does not confirm) a psychogenic component to ED symptoms that would benefit from further investigation". And the AUA recommends considering a mental health referral for men being treated by any modality, not only for men labelled psychogenic.

How common is erectile dysfunction?

This page does not give a percentage for men of a given age today, because no current figure survived reading. The AUA states that "Up to 30 million men in the United States and 150 million men worldwide are estimated to be affected by ED", which is an estimate rather than a measurement. The most widely quoted number — 52% — comes from the Massachusetts Male Aging Study, which reported "The combined prevalence of minimal, moderate and complete impotence was 52%" in men aged 40 to 70; that study also found complete impotence tripled from 5% to 15% across those thirty years. It was a community sample near Boston surveyed between 1987 and 1989 using a self-administered questionnaire, so it is a real figure about a particular group of men four decades ago and not a prevalence for you.

Can I take a PDE5 inhibitor if I am on a nitrate?

No. This is an absolute contraindication on every PDE5 inhibitor label in the United States and it is the one safety fact worth knowing before anything else. The VIAGRA label states that the drug "was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated". Intermittent counts. Recreational nitrites count. If you are on an alpha-blocker the rule is different and narrower — the label requires you to be stable on it first and to start sildenafil at 25 mg — but the nitrate rule has no version where it is a matter of timing.

Sources

1. [1]Burnett AL, Nehra A, Breau RH, et al. Erectile Dysfunction: AUA Guideline. J Urol 2018;200(3):633–641 — Guideline Statement 3: "Men should be counseled that ED is a risk marker for underlying cardiovascular disease (CVD) and other health conditions that may warrant evaluation and treatment."
2. [2]European Association of Urology, Guidelines on Sexual and Reproductive Health — chapter 5, Management of Erectile Dysfunction. Section 5.1: "Erectile dysfunction is defined as the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance"; summary of evidence: "Erectile dysfunction is a symptom, not a disease."
3. [3]Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. J Urol. 2018;200(2):423–432 — cited here only for the contrast in how the same body treats validated questionnaires on a different diagnosis.
4. [4]Feldman HA, Goldstein I, Hatzichristou DG, Krane RJ, McKinlay JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994;151(1):54–61. PMID 8254833 — "The combined prevalence of minimal, moderate and complete impotence was 52%."
5. [5]VIAGRA (sildenafil citrate) tablets — FDA prescribing information, Pfizer Laboratories Div Pfizer Inc, via DailyMed. Indications and Usage: "VIAGRA is indicated for the treatment of erectile dysfunction." Contraindications: co-administration with nitric oxide donors in any form.
6. [6]CIALIS (tadalafil) tablets — FDA prescribing information, Eli Lilly and Company, via DailyMed. Indications and Usage sections 1.1 to 1.3: erectile dysfunction; the signs and symptoms of benign prostatic hyperplasia; and both together.