Causes of Erectile Dysfunction
| Cause | Mechanism | Clues |
|---|---|---|
| Vascular (most common) | Atherosclerosis reduces penile blood flow | CVD risk factors; worse with exertion |
| Diabetic (neurovascular) | Both vascular and autonomic neuropathy | Poor glucose control; long duration |
| Hypertensive / medications | Antihypertensives, beta-blockers, SSRIs, cimetidine | Temporal link to starting medication |
| Hormonal | Low testosterone, high prolactin, hypothyroidism | Low libido; fatigue; small testes |
| Psychological | Performance anxiety, depression, relationship issues | Maintained morning erections; situational |
| Structural | Peyronie's disease (penile plaques) | Curved, painful erection |
Investigation Panel
- Fasting glucose / HbA1c — exclude diabetes
- Fasting lipids — cardiovascular risk
- Testosterone (morning, fasting) — low testosterone in ~5% of ED
- FSH, LH, prolactin — if testosterone low or libido absent
- TFTs — hypothyroidism
- BP measurement — hypertension
- Urine ACR — diabetic complications
Morning Erections — A Useful CluePreserved morning/nocturnal erections strongly suggest psychological rather than organic ED. Absent morning erections point toward vascular, hormonal, or neurological causes and warrant investigation.
How do PDE5 inhibitors (Viagra) work?
They block phosphodiesterase type 5, increasing cyclic GMP, which relaxes smooth muscle in penile arteries — increasing blood flow in response to sexual stimulation. They require sexual arousal to work — they're not aphrodisiacs.
Which PDE5 inhibitor is best?
Sildenafil (Viagra) — onset 30–60 min, 4–6 hr duration. Tadalafil (Cialis) — onset 2 hours, 36-hour duration (also available as daily 5 mg for continuous effect). All are equally effective; choice depends on preference and timing.
Can lifestyle changes improve ED?
Yes significantly. Exercise (150 min/week), stopping smoking, reducing alcohol, and weight loss can restore erectile function — often as effectively as medication. Exercise is particularly powerful — the penile artery reflects systemic vascular health.
When should I see a doctor for ED?
Any ED under age 40 warrants investigation (to exclude testicular, hormonal, or structural causes). ED in any man with cardiovascular risk factors should be assessed — it may be the earliest manifestation of systemic vascular disease.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.