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Erectile dysfunction and low testosterone
These are two different problems that are confused constantly, and both are surrounded by treatments sold at high prices without evidence to support them. Here you will find how they differ, why erectile dysfunction is often the first warning of cardiovascular disease that has not yet shown itself, and which treatments genuinely work.
Written and reviewed by
Dr. Eduardo Amaya Fragoso
Urologic Surgeon · Fellowship in Urologic Oncology (Centro Médico Nacional Siglo XXI · UNAM) · International Fellow in Robotic Urology (Instituto Israelita Albert Einstein, Brazil)
Professional Licence 10407470 · Specialty Licence 12943253 · CONAMEU 1918 (valid 2022–2027). Practice at Hospital San José, Hermosillo, Sonora.
Last reviewed: 23 July 2026
The essentials
- Erectile dysfunction is not a problem of the erection: it is a problem of the blood vessels. Which is why it tends to appear years before a heart attack.
- These are two different things and they are constantly confused: low testosterone causes lack of desire; erectile dysfunction is failing to achieve an erection even when desire is present.
- Testosterone is not a treatment for erectile dysfunction. If your levels are normal, it will not improve your erections.
- A good many of the advertised treatments —shockwave, platelet-rich plasma, "regenerative therapies"— lack sufficient evidence to be recommended outside research.
- External testosterone suppresses sperm production and can leave you infertile. Almost nobody warns of this before prescribing it.
Two different problems that get confused
It is the commonest confusion in this area and it is worth clearing up before anything else:
- Erectile dysfunction is the persistent inability to achieve or maintain an adequate erection. Desire may be entirely intact.
- Testosterone deficiency is having low levels of the hormone, and its dominant symptom is lack of desire, together with fatigue, loss of muscle mass, increased abdominal fat and low mood.
They can coexist, and often do. But they are not the same, they are not investigated the same way and they are not treated the same way. Treating one believing you are treating the other is the commonest reason a patient ends up spending money without improving.
The most important thing in this guide
The erection is a vascular thermometer
An erection depends on the arteries of the penis dilating and filling with blood. Those arteries are far narrower than the coronary arteries. When the endothelium begins to be damaged —by diabetes, hypertension, cholesterol, tobacco or inactivity— it shows first where the calibre is smallest.
Hence a consequence that changes the whole meaning of the consultation: erectile dysfunction often precedes a cardiovascular event by years. It is not a bedroom problem: it is frequently the first warning of a disease that has not yet shown itself.
For that reason, when a man comes in with this complaint, the first step is not to prescribe a tablet: it is to measure blood pressure, glucose, lipids and review habits. A proportion of these patients leave the consultation with a diagnosis of diabetes or hypertension they knew nothing about. If someone prescribes you a drug without investigating any of this, they are solving the symptom and letting the reason for it slip past.
What causes it
- Vascular, the commonest: diabetes, hypertension, raised cholesterol, smoking, obesity and inactivity.
- Neurological: spinal cord injury, multiple sclerosis, and the aftermath of pelvic surgery, radical prostatectomy included.
- Hormonal: low testosterone, thyroid disorders, raised prolactin.
- Drug-related, and frequently overlooked: some antihypertensives, antidepressants, antipsychotics and finasteride.
- Psychogenic: performance anxiety, depression, relationship difficulties. Commoner in young men and of sudden onset.
One detail that guides a great deal: if you have normal morning or night-time erections, the mechanism works and the psychological component weighs more. If they disappeared gradually, the cause is usually vascular.
What works and what does not
This is the ground where patient embarrassment is most exploited, so it is worth being explicit.
| Treatment | What backs it | Worth knowing |
|---|---|---|
| Lifestyle change | Solid evidence | Stopping smoking, losing weight and exercising improve erectile function measurably. It is the only one that also lengthens life |
| PDE5 inhibitors (sildenafil, tadalafil) | Solid evidence | First line. They work in most men. They require desire and stimulation: they do not produce erections on their own |
| Correcting the underlying cause | Solid evidence | Controlling diabetes or hypertension, adjusting a drug that is causing it |
| Vacuum device | Reasonable evidence | Effective and drug-free. Unpopular, but useful above all after prostate surgery |
| Intracavernosal injections | Highly effective | They work even when tablets no longer do. They require teaching and getting past the initial reluctance |
| Penile prosthesis | The highest satisfaction of all | The definitive solution when everything else has failed. It is surgery and irreversible, but satisfaction rates are the highest in all of urology |
| Testosterone | Only if documented as low | If your levels are normal, it does not improve erections |
| Shockwave therapy | Evidence still insufficient | Results vary between studies and protocols do not agree. Research continues; it should not be sold as established treatment |
| Platelet-rich plasma, stem cells | No evidence to support it | Not recommended outside research protocols. It is charged for dearly |
Put plainly
The last three rows are the reason I wrote this guide. There are clinics charging very expensive packages of shockwave and plasma and presenting them as established treatment. They are not: they are research avenues with inconsistent results. They may one day be established; today they are not.
What does work is well established and not expensive: correct the vascular problem, a tablet, and if that is not enough, injections or a prosthesis. That resolves the vast majority of cases.
Testosterone deficiency
It is real, it is treatable, and it is also one of the most overused diagnoses in current medicine.
How it is actually diagnosed
- With compatible symptoms —lack of desire, fatigue, loss of muscle mass, low mood— plus confirmed low levels.
- Two measurements on different days, taken in the morning and fasting. Testosterone varies through the day: a single afternoon sample is no basis for a diagnosis.
- With additional testing of luteinising hormone, prolactin and haematocrit, because some causes call for a different approach.
Before agreeing to testosterone, two warnings
First: it suppresses fertility. External testosterone switches off the signal the brain sends to the testicle and, with it, sperm production. It can cause infertility, sometimes lasting well beyond stopping it. If you intend to have children, tell your doctor before starting, because there are alternatives that raise testosterone without switching off fertility.
Second: if the problem is weight, testosterone is not the answer. Obesity lowers testosterone, and losing weight raises it. A considerable proportion of the men it is prescribed to would improve as much or more by losing weight, sleeping better and training with weights. It is slower, it is less profitable for whoever sells it, and it works.
And one important qualification for your own case: testosterone is not a treatment for erectile dysfunction if your levels are normal. Restoring it improves desire, not necessarily the erection.
If you have had prostate surgery
This is a different situation and deserves saying separately. After radical prostatectomy, recovery of erections depends on whether the neurovascular bundles were spared, on your previous function and on your age, and it can take twelve to twenty-four months.
- Starting rehabilitation early —low-dose tablets, a vacuum device or injections— appears to favour recovery.
- It not working at three months does not mean it will not work. That is the point at which many patients give up.
- If after two years recovery is insufficient, a prosthesis remains available and with excellent results.
A complaint almost nobody investigates properly
Why it matters who looks after you
Erectile dysfunction is the urological complaint where most is sold and least is investigated. Prescribing the tablet is easy; working out why it appeared is not.
- Looking for the disease behind itBlood pressure, glucose, lipids and habits, before any prescription. A proportion of these patients have undiagnosed diabetes or hypertension, and the erection was the warning.
- Telling the hormonal problem from the vascular oneLack of desire and lack of erection point to different places. Measuring testosterone properly —twice, in the morning— and not treating with hormones a problem that is not hormonal.
- Saying no to what is unprovenSelling a shockwave package is more profitable than explaining why the evidence does not yet support it. It is not offered here.
- Having the whole ladderTablets, vacuum device, injections and prosthesis. When the whole ladder exists, there is no need to insist on a rung that no longer works.
In short: this complaint deserves a medical investigation, not a catalogue of services.
A urologic oncologist is a urologist who additionally completed a postgraduate fellowship devoted solely to urological cancer. Mine was at Centro Médico Nacional Siglo XXI, accredited by UNAM. It can be verified. What exactly changes →
Related guides
- Localized prostate cancer — continence and sexual function after surgery.
- Enlarged prostate and HoLEP — including retrograde ejaculation.
- Vasectomy — why it affects neither erections nor testosterone.
- All patient guides
Very good care, trust, and above all he gives you an explanation of the condition you are seeing him for. Recommended 100%.
F. M. M. Verified appointment · 
Doctoralia · translated from Spanish
Dr. Eduardo Amaya Fragoso
Urologic Oncologist · Robotic Surgeon
Have you been living with this without seeking help?
It is the complaint most often postponed and one of the few where the symptom may be warning of something larger. One consultation with basic tests settles in a week what many carry for years.
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Note
This information is for general guidance and does not replace a medical consultation: do not make decisions based on this text without discussing them with your urologist.