Erectile dysfunction: causes, red flags, and what actually works
ED is common, treatable, and often a useful early signal about cardiovascular and hormonal health. Here is how clinicians think about it.
Key points
- Roughly 40% of men have some ED by age 40, rising with each decade.
- ED is often vascular — it can be an early warning for heart disease.
- PDE5 inhibitors (sildenafil, tadalafil) work for the majority of men with uncomplicated ED.
- If ED is paired with low libido and fatigue, testosterone deserves a look.
The mechanical picture
An erection is a vascular event. Arousal triggers nitric oxide release in penile tissue, which relaxes smooth muscle and lets blood flow in faster than it leaves. Anything that disrupts that pipeline — narrowed arteries, low testosterone, nerve damage, high anxiety, certain medications — can produce ED.
That is why ED is often the first visible symptom of early cardiovascular disease. The arteries in the penis are small and show stiffness years before the ones in the heart do.
First-line treatments
PDE5 inhibitors — sildenafil (Viagra), tadalafil (Cialis), vardenafil — are the default for most men. They amplify the nitric oxide signal so blood flow responds to arousal more reliably. Tadalafil has a longer window (24-36 hours) which many men prefer for spontaneity; sildenafil is cheaper and more on-demand.
These work in roughly 70% of men with uncomplicated ED. They do not create desire — arousal still has to happen for them to work.
When to look deeper
If ED is paired with morning fatigue, low libido, weight gain, and poor sleep, get testosterone and a metabolic panel checked. If ED came on suddenly after starting a new medication (SSRIs, beta blockers, finasteride), the medication may be the cause.
If PDE5 inhibitors do not work at full dose, that is a signal to escalate to vascular workup, not just try another pill.