ED（勃起不全）の解明

勃起不全（ED） is one of the most common medical conditions among men in Singapore, and one of the least discussed. Men who would book a specialist appointment within a week for chest pain will live with erection problems for two or three years before saying a word to anyone. In that silence, two things happen. The first is that a treatable problem goes untreated. The second, and more serious, is that a warning sign about the health of the blood vessels goes unheard.

This guide sets out what 勃起不全 actually is, the physiology behind it, why it happens, what a proper assessment should involve, and what the current treatment options genuinely deliver. It is written for men across Singapore, from Jurong to Tampines to Woodlands, and it assumes no medical background.

What erectile dysfunction actually means

Erectile dysfunction, or ED, is the persistent inability to achieve or maintain an erection firm enough for satisfying sexual activity. Three words in that definition carry the weight.

Persistent. Every man has occasional failures. Fatigue, stress, alcohol, an unfamiliar partner, a bad week at work. Studies suggest that difficulty in fewer than one in five encounters sits within normal variation. ED is diagnosed when the difficulty is consistent over roughly three months or more.

Maintain. Losing an erection partway through counts. A large number of men assume ED means being unable to get an erection at all, and so do not recognise their own symptom. Losing rigidity after penetration is one of the most common early presentations of vascular ED.

Satisfying. The benchmark is not a number on a scale. It is whether erectile function allows the sexual life you and your partner want. Some men present with erections that are technically adequate but noticeably softer than they were five years ago. That change is worth investigating.

How common is it

Population studies across Asia consistently put the prevalence of some degree of ED at around one in three adult men, rising steeply with age. Roughly a quarter of men in their forties report symptoms; by the seventies, the majority do. But the trend that matters most in Singapore is the younger end of the curve. Clinics here see a meaningful number of men in their late twenties and thirties, driven by a combination of metabolic disease, sedentary desk work, chronic sleep deprivation, and anxiety.

How an erection works

An erection is a vascular event that requires a nervous system, a hormonal environment and a set of blood vessels all working in sequence.

Arousal, whether physical or psychological, triggers nerve endings in the penis to release nitric oxide. Nitric oxide relaxes the smooth muscle lining the arteries feeding the two spongy chambers of the penis, the corpora cavernosa. Relaxed arteries dilate, and blood floods into the chambers. As they expand, they compress the veins that would normally drain them against the surrounding fibrous sheath, trapping the blood inside. That trapping mechanism, called the veno-occlusive mechanism, is what turns increased blood flow into rigidity.

Four systems therefore have to work: intact nerve signalling, sufficient arterial inflow, healthy smooth muscle capable of relaxing, and a competent veno-occlusive mechanism. Testosterone underpins the whole system by maintaining libido and the health of the erectile tissue itself. A failure at any point produces the same symptom.

Why erectile dysfunction is a cardiovascular warning

This is the single most important thing to understand about ED, and the reason it should never be treated as a purely bedroom concern.

The arteries supplying the penis are roughly one to two millimetres in diameter. The coronary arteries supplying the heart are three to four millimetres. Atherosclerosis, the process of plaque building up in artery walls, affects the whole arterial tree at a similar rate. When plaque narrows arteries everywhere by the same proportion, the smallest vessels lose function first.

The practical consequence is that vascular ED typically appears three to five years before a cardiac event. Multiple longitudinal studies have found that men presenting with new ED carry a significantly elevated risk of heart attack and stroke over the following decade, independent of other risk factors. ED is, in effect, an early warning system running years ahead of the symptom most men wait for.

This is why any man presenting with ED should also be assessed for cardiovascular risk. A comprehensive health screening covering lipids, glucose, blood pressure and kidney function is not an upsell on an ED consultation. It is the point of it.

The main causes

ED is usually multifactorial. In most men over forty there is a physical process underway with a psychological layer built on top of it.

Vascular causes

The largest single category. Atherosclerosis, high blood pressure and high cholesterol all reduce the arterial inflow needed for rigidity. This is the mechanism behind the strong link between ED and cardiac risk.

Metabolic causes

Diabetes is the heaviest hitter. Around half of men with diabetes develop ED, often a decade earlier than men without it, because chronically raised glucose damages both the small blood vessels and the nerves that trigger nitric oxide release. Prediabetes counts too. Obesity contributes independently through inflammation, insulin resistance and the conversion of testosterone to oestrogen in fat tissue.

Hormonal causes

Low testosterone reduces libido and impairs the health of erectile tissue. It is worth noting that low testosterone rarely causes ED in isolation, and that treating it in a man whose real problem is vascular will disappoint. Thyroid disorders and raised prolactin are less common but readily testable causes. See our overview of テストステロン欠乏症 for detail.

Neurological causes

Spinal injury, multiple sclerosis, Parkinson's disease, and pelvic surgery, particularly prostate surgery, can interrupt the nerve pathway. Long-distance cycling on an unsuitable saddle can cause reversible perineal nerve compression.

Medications

A long list, and one that is commonly overlooked. Certain blood pressure drugs, particularly older beta-blockers and thiazide diuretics, some antidepressants, especially SSRIs, finasteride used for hair loss, and some antipsychotics. Never stop a prescribed medication on your own. Do raise it with your doctor, because alternatives frequently exist.

Lifestyle

Smoking is directly toxic to the endothelium, the inner lining of blood vessels, and is one of the strongest modifiable risk factors. Heavy alcohol use, recreational drugs, chronic sleep deprivation and untreated obstructive sleep apnoea all contribute. Sleep apnoea is under-diagnosed in Singapore and is worth considering in any man who snores heavily and wakes unrefreshed.

Psychological factors

Performance anxiety, depression, relationship strain, and work stress. In Singapore's high-pressure working culture, this layer is rarely absent. Psychological ED tends to be abrupt in onset, situational, and accompanied by preserved morning erections.

Physical or psychological: how to tell

Neither pattern is diagnostic on its own, but the distinction guides the assessment.

Feature	More likely physical	More likely psychological
Onset	Gradual over months or years	Sudden, often traceable to an event
Morning erections	Reduced or absent	Usually preserved
Situation	Present in every situation	Situational, varies by partner or setting
Erections with self-stimulation	Also impaired	Often normal
Associated features	Risk factors, other vascular symptoms	Anxiety, low mood, relationship strain

Preserved morning and self-stimulation erections strongly suggest the hardware works and the problem lies elsewhere. Their absence points towards a vascular, hormonal or neurological cause.

What a proper assessment involves

A consultation that ends with a prescription and nothing else has skipped most of the work.

History. Onset, pattern, morning erections, libido, ejaculation and orgasm, relationship context, medication list, alcohol and tobacco, sleep quality, mood.

Examination. Blood pressure, waist circumference and body mass index, examination of the penis for plaques or curvature suggesting Peyronie's disease, testicular size and consistency, and signs of low testosterone.

Blood tests. Fasting glucose and HbA1c, a full lipid panel, morning total testosterone with free testosterone or SHBG where indicated, thyroid function, prolactin if libido is low, kidney and liver function, and a full blood count.

Cardiovascular risk assessment. Because of everything described above, an ED consultation is a legitimate trigger for a broader cardiac risk review, including an ECG where appropriate.

Specialist investigation. A minority of cases warrant penile Doppler ultrasound, which measures arterial inflow and looks for venous leak. It is not a first-line test.

Treatment options and what they realistically deliver

Risk factor modification

Unglamorous and genuinely effective. Weight loss of ten percent, structured aerobic exercise, smoking cessation and improved glycaemic control all measurably improve erectile function in trial settings. Exercise in particular has a meta-analysis-level evidence base. It is slow, it takes months, and it is the only intervention that also lowers your cardiovascular risk.

PDE5 inhibitors

Sildenafil, tadalafil, vardenafil and avanafil. These block the enzyme that breaks down the signalling molecule downstream of nitric oxide, amplifying the natural erectile response. They do not create erections; arousal is still required. Response rates run around seventy percent in unselected men, lower in men with long-standing diabetes.

In Singapore these are prescription-only medicines. Buying them from unregulated online sources is a real and documented risk, with counterfeit products containing incorrect doses or undeclared substances. They are also absolutely contraindicated with nitrate medications used for angina, which is one of several reasons a proper consultation matters.

A common reason for apparent treatment failure is incorrect use rather than genuine non-response: too low a dose, taken with a heavy meal, or without sufficient sexual stimulation. Guidelines recommend trialling a drug properly on several occasions before concluding it does not work.

Shockwave therapy

Low-intensity extracorporeal shockwave therapy aims to stimulate new blood vessel growth in the penis rather than to force a single erection. It is the only widely available option that targets the underlying vascular problem, and unlike tablets its benefit persists between sessions. It suits men with mild to moderate vascular ED best. Our detailed article on extracorporeal shockwave therapy covers the mechanism and the evidence, and the treatment itself is described on our ESWT service page.

Vacuum erection devices

A mechanical pump that draws blood into the penis, held by a constriction ring. Effective, drug-free, and useful for men who cannot take PDE5 inhibitors or who are in penile rehabilitation after prostate surgery. The main barrier is that many men find it unspontaneous.

Intracavernosal injections

A very fine needle delivers alprostadil directly into the erectile tissue. Success rates exceed eighty percent, including in men who do not respond to tablets, because the drug bypasses the nitric oxide pathway. It requires training and carries a small risk of prolonged erection, which is a medical emergency.

Testosterone replacement

Appropriate only where testosterone is genuinely and repeatedly low on morning testing, alongside symptoms. It improves libido reliably and erectile function variably. It requires monitoring and has fertility implications that should be discussed before starting.

Psychological therapy

Cognitive behavioural approaches and sex therapy, ideally involving the partner, are the appropriate treatment for performance anxiety and are a valuable adjunct in almost every case. Combining medication with therapy outperforms either alone for men with a significant psychogenic component.

Penile implants

Surgical, permanent, and reserved for men who have exhausted other options. Satisfaction rates in appropriately selected patients are among the highest of any treatment in urology.

When to see a doctor

Do not wait. Book an appointment if difficulty has persisted for around three months, if the change was abrupt, if it followed a new medication, if it accompanies low libido or fatigue, if there is pain or curvature, or if you have diabetes, high blood pressure or a family history of early heart disease.

Seek urgent care for an erection lasting more than four hours. Priapism is a surgical emergency and delays cause permanent damage.

Getting assessed in Singapore

Hisential is a men's health clinic serving patients from across Singapore, with consultations covering assessment, testing and treatment in a single visit. Men travel to us from the east, west and north of the island, and follow-up reviews can often be handled remotely once a treatment plan is in place. The clinic is located on Orchard Road, a short walk from Orchard MRT, with a private waiting area. Consultation is from S$50 after GST before any investigations or treatment.

Frequently asked questions

Is erectile dysfunction a normal part of ageing?

Erectile function does change with age, but ED is not an inevitable consequence of getting older. It is a medical condition with identifiable causes, and in most men something can be done about it. Treating it as inevitable means missing the cardiovascular signal it often carries.

Can erectile dysfunction be cured, or only managed?

Both, depending on the cause. Psychogenic ED, medication-induced ED and ED driven by reversible factors such as poor glycaemic control or heavy alcohol use can genuinely resolve. Established vascular ED is usually managed rather than cured, though shockwave therapy and aggressive risk factor control can produce lasting improvement.

Do I need to fast before ED blood tests?

Usually yes, since glucose and lipid measurements are most accurate fasting. Testosterone should be drawn in the morning, ideally before eleven, because levels fall through the day. A single early morning fasting appointment covers everything.

Are online ED medications safe?

Products from unlicensed overseas websites are a documented source of counterfeit medication in this region, with wrong doses and undeclared ingredients found in seized samples. PDE5 inhibitors are prescription-only in Singapore for good reason, including their dangerous interaction with nitrates. Get them from a licensed clinic or pharmacy.

Is ED linked to premature ejaculation?

They frequently coexist, and one can drive the other. Some men rush to ejaculate before losing an erection, which over time entrenches a pattern of premature ejaculation. Assessment should cover both.

Will my consultation be confidential?

Yes. Medical confidentiality applies to everything discussed, and consultations are conducted privately.

References

• Singapore Ministry of Health, National Population Health Survey, cardiovascular risk factor data.
• Health Promotion Board Singapore, guidance on physical activity, smoking cessation and diabetes prevention.
• European Association of Urology, Guidelines on Sexual and Reproductive Health.
• American Urological Association, Erectile Dysfunction Guideline.
• Vlachopoulos C et al., Prediction of cardiovascular events with erectile dysfunction, systematic review and meta-analysis.