Short answer: an erection is a vascular event. It requires healthy blood vessels, adequate nerve signalling, sufficient testosterone and an unpreoccupied mind. Erectile dysfunction means one of those has been disrupted — and because the vascular route is the most common, ED is frequently the first visible sign of a circulatory problem elsewhere.
Erectile dysfunction can precede a cardiovascular event — heart attack or stroke — by several years. The arteries supplying the penis are narrower than the coronary arteries, so they show furring first. New or worsening ED is a reason to have blood pressure, cholesterol and blood glucose checked, even if you feel completely well otherwise. This is not scaremongering; it is the most valuable thing ED tells you.
What counts as ED
Persistent difficulty getting or keeping an erection sufficient for satisfying sex. Occasional difficulty is universal and means nothing on its own — tiredness, alcohol, stress and unfamiliarity all cause it. The clinical threshold is roughly three months of consistent difficulty.
Physical causes
Vascular
The most common category. Atherosclerosis, high blood pressure, high cholesterol, diabetes and smoking all reduce blood flow, and the penile arteries are affected early. Diabetes compounds this by damaging nerves as well as vessels.
Hormonal
Low testosterone more often reduces desire than the mechanics of erection, but it contributes, and it is straightforward to measure. Thyroid dysfunction and raised prolactin can both be involved.
Medication
Beta-blockers, thiazide diuretics, SSRIs, antipsychotics and finasteride are all recognised contributors. If ED began within weeks of starting something new, tell the prescriber — do not stop it yourself.
Neurological and surgical
Multiple sclerosis, Parkinson's, spinal injury and pelvic or prostate surgery can all affect the nerve supply. See prostate health and sex.
Psychological causes
Performance anxiety, depression, stress and relationship difficulty are genuine causes rather than a diagnosis of exclusion — and they interact viciously with physical ones. A few physically-caused failures generate anxiety, and the anxiety then sustains the problem after the physical trigger has gone. See sexual performance anxiety.
A useful distinguishing question
Do you still get spontaneous erections on waking? If morning erections are preserved and difficulty only occurs with a partner, that points toward a psychological or situational component. If they have disappeared too, that points toward a physical cause. This is a rule of thumb, not a test — plenty of men have both.
Check the measurable causes
Testosterone and full male hormone panels analysed by a UKAS-accredited UK laboratory. Morning sample, discreet plain packaging, results against standard reference ranges.
See the male hormone testWhat actually helps
- See a GP. ED is one of the few sexual complaints where the medical route is clearly first — both because treatment is effective and because of what it may be signalling.
- Cardiovascular risk factors. Stopping smoking, treating blood pressure and cholesterol, managing blood glucose and losing excess weight improve erectile function and everything downstream of circulation.
- Exercise. Aerobic exercise has a genuine evidence base here, via endothelial function. It is not a consolation prize.
- Alcohol. Reliably makes it worse, acutely and chronically.
- Prescribed treatment. PDE5 inhibitors are effective for most men and available via a GP or pharmacist. Buying them from unregulated websites is a genuinely bad idea — counterfeit products are common and the underlying cause goes uninvestigated.
- Psychosexual therapy where anxiety is driving or sustaining it.
ED is new or worsening, you have not had your blood pressure, cholesterol or blood glucose checked recently, you have chest pain or breathlessness on exertion, or ED appeared alongside other symptoms. Treatment is straightforward; the assessment behind it is the valuable part.
Common questions
Is erectile dysfunction a sign of heart problems?
It can be an early one. The arteries supplying the penis are narrower than the coronary arteries, so reduced blood flow shows there first — sometimes years before cardiac symptoms. New or worsening ED is a good reason to have blood pressure, cholesterol and blood glucose checked.
Does low testosterone cause erectile dysfunction?
It contributes more often to low desire than to the mechanics of an erection, but it can play a part and is easily measured. Testosterone is highest in the morning, so a morning sample is needed.
What blood tests are useful for ED?
Testosterone, and a broader male hormone panel covering thyroid and prolactin. Blood glucose, cholesterol and blood pressure matter at least as much and are usually done through a GP.
Is ED just a normal part of getting older?
It becomes more common with age but is not an inevitable consequence of it, and treating it as inevitable means missing the cardiovascular and metabolic causes underneath.
Can anxiety alone cause erectile dysfunction?
Yes, and it commonly sustains ED that began physically. If morning erections are preserved and difficulty happens only with a partner, a psychological component is likely.
Should I buy ED medication online?
Not from unregulated sellers. Counterfeit products are widespread, some interact dangerously with heart medication, and self-treating leaves the underlying cause uninvestigated. A GP or a registered pharmacist is the right route.