Erectile Dysfunction: What It May Be Telling You About Your Heart

ED is usually a blood-vessel problem — which means it is often the first visible sign of a vascular disease that has not reached your heart yet. That is the most important thing on this page.

⛔ Start Here: The Cardiovascular Check

The arteries that supply the penis are 1-2 mm across. The coronary arteries are three to four times wider. The same disease process — endothelial dysfunction and atherosclerosis — narrows both, and it produces symptoms in the smaller vessels first.

That is why erectile dysfunction is a sentinel symptom. In the COBRA study of men with coronary artery disease and ED, sexual dysfunction preceded the cardiac disease in 93%, by a mean of 24 months (interquartile range 12-36)².

What to ask for, from your own doctor

Do this whether or not you ever pursue any treatment on this page. These are ordinary primary-care tests, they are usually free or cheap, and they need someone who will follow the results for years:

We would rather you booked that appointment than booked with us. If you only do one thing after reading this page, do that one.

⛔ The one drug interaction you must know

PDE5 inhibitors and nitrates must never be combined. Nitrates include glyceryl trinitrate (GTN spray or patches), isosorbide mononitrate and dinitrate, and recreational "poppers" (amyl nitrite). Together with sildenafil or tadalafil they can cause a profound and dangerous fall in blood pressure.

If you take a nitrate for angina, PDE5 inhibitors are contraindicated for you — and that fact is itself a reason to have your heart disease properly reviewed.

Find the Cause Before Treating the Symptom

ED is a symptom with a long differential⁴, and several of its causes are common, reversible, and cost nothing to fix. A vascular workup that goes straight to blood-flow measurement will miss them.

⚠️ A useful discriminator you can apply yourself: if you still have firm spontaneous or morning erections, the vascular machinery is largely intact and the cause is more likely psychological, medication-related or hormonal. If those have gone too, the cause is more likely organic.

Understanding ED: The Vascular Science

How erections work

1. Neural signalling — sexual stimulation triggers parasympathetic impulses to the penile vasculature
2. Nitric oxide release — endothelial cells lining the cavernosal arteries release NO
3. Smooth muscle relaxation — NO raises cyclic GMP, relaxing cavernosal smooth muscle
4. Arterial dilation — inflow rises sharply
5. Veno-occlusion — expanding sinusoids compress subtunical venules against the tunica albuginea, trapping blood
6. Rigidity — intracavernosal pressure rises to produce firmness

PDE5 inhibitors work at step 3, by preventing the breakdown of cyclic GMP. They amplify a signal that still has to be generated — which is why they need sexual stimulation to work, and why they work less well when the endothelium is badly damaged.

What goes wrong

Endothelial dysfunction — damaged endothelium produces less nitric oxide. Driven by atherosclerosis, diabetes, hypertension, smoking and metabolic syndrome: the same process as coronary disease, in smaller vessels².

Cavernosal smooth muscle changes — chronic reduced flow leads to smooth muscle loss and replacement by collagen, making the tissue less expandable.

Neuropathy — diabetes, prostate surgery or spinal injury can interrupt the signal before the vascular cascade begins.

Hormonal factors — low testosterone reduces libido and contributes to tissue changes, though hormonal treatment alone rarely resolves established ED when vascular damage is present.

Treatment: What the Evidence Supports

First-line: PDE5 inhibitors

Sildenafil and tadalafil are the current first-line treatment for ED³. They work for the majority of men, they have decades of safety data, and they are now cheap generics.

Their real limitations, stated fairly³: they are taken on demand rather than curative; some men cannot tolerate them; and efficacy is more variable in complex patients — men with multiple comorbidities, advanced diabetes, or ED after pelvic surgery. ⛔ And they are absolutely contraindicated with nitrates.

They do not repair the underlying blood vessels. That is a real limitation and it is the honest argument for investigating something else. It is not an argument for skipping them.

Other established options

Intracavernosal injection (alprostadil), vacuum erection devices, and penile prosthesis all work, with the trade-offs their names suggest. A prosthesis has the highest satisfaction rates of any ED treatment in men for whom other options have failed, and is worth discussing rather than dismissing.

The yardstick: what counts as a real improvement

The standard outcome measure is the IIEF Erectile Function domain (IIEF-EF), scored 0-30. Almost every trial below reports it, so it is worth knowing what size of change matters.

From an anchor-based analysis of 17 randomised placebo-controlled trials and 3,345 patients, the minimal clinically important difference (MCID) is⁵:

Hold every number below against that table.

Low-intensity shockwave therapy (Li-ESWT)

This is the best-evidenced of the regenerative options, and we are going to report it precisely rather than favourably.

Lu et al. (2017)⁶ — systematic review and meta-analysis, 14 studies, 833 patients, 7 of them RCTs:

• Mean difference in IIEF: 2.00 points (95% CI 0.99-3.00; p < 0.0001) ⚠️ The whole confidence interval lies below the overall MCID of 4. It reaches the threshold only for men with mild ED — which is consistent with the review's own finding that "patients with mild-moderate ED had better therapeutic efficacy than patients with more severe ED or comorbidities."
• Erection Hardness Score also improved (risk difference 0.16, 95% CI 0.04-0.29)
• ⚠️ Durability: the authors state efficacy "could last at least 3 months." Not 6-12
• The authors note that setup parameters and protocols varied widely between studies, and call for "robust evidence from additional RCTs and longer-term follow-up."

Vardi et al. (2012)⁷ — the first double-blind, sham-controlled RCT, 67 men randomised 2:1:

• IIEF-EF rose 6.7 ± 0.9 in the treated group vs 3.0 ± 1.4 in sham (p = 0.0322)
• ⭐ The most striking result, and the one usually left out: 19 men in the treated group who could not previously achieve erections firm enough for penetration could afterwards — versus none in the sham group
• Penile haemodynamics improved in the treated group
• ⚠️ Follow-up was one month after the final treatment. The paper is titled "Short-Term Results." It does not demonstrate durability
• ⚠️ Population: men who were already PDE5-inhibitor responders, after a one-month washout. It does not tell you what happens in men for whom tablets have failed

Cayan et al. (2026)⁸ — systematic review and meta-analysis, 12 studies. This is the most important recent result and it cuts both ways:

⚠️ The questionnaire scores improve. Whether penetration and intercourse actually happened did not differ, and no penile Doppler measurement differed. That is an uncomfortable result for a treatment whose entire rationale is vascular restoration, and it belongs beside the positive numbers rather than after them.

In post-prostatectomy ED specifically, a 2026 meta-analysis of 5 RCTs and 297 patients found significant IIEF improvement at 8 weeks (MD 2.80) and 12 weeks (MD 2.10) but no significant difference at 24 weeks and beyond⁹. ⚠️ This paper carries a publisher's Correction issued in July 2026 whose content we were unable to retrieve; we are flagging that rather than relying on the paper alone. Its conclusion is consistent with Lu's "at least 3 months."

Platelet-rich plasma

Poulios et al. (2021)¹⁰ — the first double-blind, randomised, placebo-controlled trial, 60 men with mild to moderate ED (30 PRP, 30 saline), two sessions a month apart, followed to 6 months. The MCID was the primary endpoint, which is the right way to run this trial:

• 20/29 (69%) of PRP patients reached the MCID vs 7/26 (27%) of placebo patients
• Risk difference 42% (95% CI 18-66), p < 0.001
• Baseline-adjusted mean between-group difference 3.9 IIEF-EF points (95% CI 1.8-5.9)
• No adverse events in either group

⚠️ The authors' own limitations, in their words: the findings "lack external validity due to single-center design" and "cannot be extrapolated to other PRP separation systems." The trial used one FDA-approved system at one centre. It does not establish that PRP as sold elsewhere performs the same way.

A broader review of PRP in male sexual dysfunction concludes that it shows promise but that larger, well-designed RCTs are needed before clinical recommendations can be made¹¹.

Stem cell therapy — investigational

Haahr et al. (2016)¹² — Phase 1, open-label, single-arm, no control group, 17 men with ED after radical prostatectomy, followed 6 months:

• Safe and well tolerated; only minor events related to the liposuction and injection
• 8 of 17 men (47%) recovered erectile function sufficient for intercourse
• ⚠️ But the effect was confined to one subgroup. On post-hoc stratification by urinary continence: 8 of 11 continent men recovered, while incontinent men did not regain erectile function at all (median IIEF 5 at 1, 3 and 6 months; p > 0.9999)

Yiou et al. (2016)¹³ — Phase 1/2 dose-escalation pilot, 12 men with post-prostatectomy ED refractory to maximal medical treatment, four dose groups:

• No serious side effects
• Significant improvement at 6 months in IIEF-15 erectile function (17.4 ± 8.9 vs 7.3 ± 4.5, p = 0.006) and intercourse satisfaction
• Spontaneous erections improved more at higher doses; benefits sustained at 1 year
• Improvement in peak systolic velocity on colour duplex Doppler and in the penile nitric oxide release test
• The authors: "Our results need to be confirmed by phase 2 clinical trials."

Where this leaves the regenerative field

A review of the whole area — platelet-rich plasma, amniotic membranes, shockwave therapy and stem cells — reaches a conclusion we are going to quote rather than paraphrase³:

"Most of these approaches have preclinical and occasionally clinical data to support their ongoing investigation; however, none of these treatments are currently supported for use in ED patients outside of clinical trials."

Our position: Li-ESWT is the best-evidenced of these and is a reasonable option for men with mild to moderate vasculogenic ED who have tried first-line treatment. Its measured effect is smaller than its reputation, its durability is demonstrated to about three months, and the objective vascular measurements do not move in pooled analysis. PRP has one good trial with acknowledged limits. Stem cell therapy is research, and we will say so.

Summary

Our Approach

Assessment

• Confidential history, including a full medication review and screening for the causes listed above
• Blood panel: testosterone, metabolic markers; prolactin and thyroid where indicated
• Penile Doppler ultrasonography where an organic vascular cause is suspected
• Cardiovascular risk review

⚠️ On the cardiovascular part: we will do this, and you should also have it done by your own doctor. We see you for a week. Blood pressure, lipids and glucose need someone who will follow them for the next twenty years, and in most countries that costs you nothing. If you have not had those checked, please do that regardless of whether you ever come here.

Treatment

• Li-ESWT where indicated, with the effect sizes above stated before you decide
• PRP where indicated
• Pelvic floor physiotherapy — cheap, evidence-based, and under-used
• Management of reversible causes identified at assessment

⚠️ We are not publishing a week-by-week results timeline. The trials measured at fixed research timepoints and none of them supports a milestone calendar.

Candidacy

May be appropriate

• Mild to moderate vasculogenic ED, after first-line treatment has been tried
• Partial PDE5-inhibitor responders wanting to reduce reliance on tablets
• Men who have understood that the pooled Li-ESWT effect is below the MCID for moderate and severe ED

Not appropriate

• ⛔ Men who have not had their cardiovascular risk assessed — that comes first
• ⛔ Men taking nitrates, without a proper cardiology review
• ⛔ ED whose cause has not been established, particularly where a medication is the likely culprit
• ⛔ Purely psychogenic ED — psychological and relationship intervention is more likely to help
• ⛔ Uncontrolled cardiovascular disease, until stabilised
• ⛔ Untreated Peyronie's disease, which needs its own assessment

Frequently Asked Questions

Q: Is ED really a warning sign for heart disease?

A: Yes, and it is the most useful thing this page can tell you. In men with coronary artery disease who also had ED, the ED came first in 93% of cases, by a mean of about two years². Get your blood pressure, lipids and glucose checked.

Q: Should I just take Viagra?

A: For most men, that is the correct first step — PDE5 inhibitors are first-line³, effective, and inexpensive. ⛔ Not if you take nitrates. And a tablet does not remove the reason to have your cardiovascular risk assessed.

Q: Does shockwave therapy work?

A: Partly, and less dramatically than it is usually sold. Questionnaire scores improve significantly across pooled trials^6,8, but the average improvement in the main meta-analysis is below the threshold for a clinically important change^5,6, and a 2026 pooled analysis found no significant effect on whether penetration or intercourse actually occurred, or on any Doppler measurement⁸. It is a reasonable option for mild to moderate ED. It is not a restoration of vascular function that has been demonstrated.

Q: Will it get rid of my need for tablets?

A: Sometimes, in some men, for a period that has been demonstrated to about three months and is contested beyond six^6,9. We are not going to promise you will stop needing medication.

Q: Can stem cells cure ED?

A: No. The human evidence is two small uncontrolled pilot studies^12,13, and in the larger of them the benefit was confined to men who were continent after prostatectomy — those who were incontinent recovered nothing. A review of the field states that none of these treatments is supported for use outside clinical trials³.

Q: How is this different from what I see advertised online?

A: The market for men's sexual health is full of unregulated and poorly evidenced offerings, and "shockwave clinics" and branded injection packages are a large part of it. What we will do is give you the effect sizes and the confidence intervals, tell you where the evidence stops, and tell you to see your own doctor about your heart. What you should ask any provider: what is the effect size, against what comparator, and for how long was it measured?

Q: I'm diabetic — will this work for me?

A: Diabetic ED has both vascular and neurological components and responds less well. The main meta-analysis found better results in men with mild-moderate ED and worse results in those with more severe ED or comorbidities⁶. Glycaemic control and cardiovascular risk management matter more here than any procedure.

Q: Is the PRP injection painful?

A: Topical anaesthetic and/or a penile block is used. Most men report pressure rather than pain, with mild soreness for a day or two. No adverse events were reported in the randomised trial¹⁰.

Take the Next Step

⛔ Before anything else: book a cardiovascular risk check with your own doctor. Blood pressure, lipids, HbA1c, smoking. It is free or cheap almost everywhere, and it is the part of this that could matter most.

Then, if you want to discuss what is realistic:

• Take our 2-minute Health Assessment — completely confidential
• Book a Discovery Consultation

If you have not tried first-line treatment, or your ED started after a new medication, we will tell you to address that first.