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Evidence reviewed August 2026InvestigationalNo standard protocol

ED Treatment: Where Stem Cell Research Stands Now

Human studies have reported improvements in erectile-function scores, erection hardness and blood-flow measures after intracavernosal stem cell interventions. But the evidence is still small and inconsistent—which is why stem cell therapy is considered investigational, not established ED care.[1][2]

InvestigationalNot established routine ED care
11 trials in one 2025 reviewOnly 6 studies / 75 patients could be pooled
No standard protocolCell source, dose and schedule vary

A diagnosis, eligibility and treatment decisions have to be made by licensed physicians. Nobody can promise an individual result, a permanent cure or independence from medication.

Stem cell research and regenerative medicine laboratory work related to ED treatment research
What human studies actually show

There is a measurable signal, but the evidence base is still small

01Evidence

A 2025 BMC Urology review found 11 clinical trials. Six studies, covering 75 patients, could be pooled; only one of them was randomized and controlled. At 6 months, pooled IIEF-5, IIEF-EF, EHS and peak systolic velocity improved, but the authors were clear: the evidence isn’t ready for widespread clinical use.[2]

A separate 2025 review screened 1,773 records and included 17 human studies with 269 patients. All used intracavernosal administration, but cell source, dose, injection site and number of injections were not standardized; some studies reported declining benefit over time.[3]

11clinical trials in the systematic review
75patients across the 6 studies included in quantitative pooling.
1randomized controlled trial in the review; most studies were early-phase or single-arm.
2 / 6 / 3studies rated good / fair / poor quality by the review authors.

AUA guidance calls intracavernosal stem cell therapy investigational, while the European Society for Sexual Medicine states that cell therapy for male sexual dysfunction should remain within Ethics Committee-approved clinical trials.[1][9]

See What May Apply to Me
Does the research fit your case?

Your ED mechanism matters before any regenerative option is discussed

02Fit
Patient record review for erectile dysfunction and regenerative medicine research eligibility
Diabetes or vascular ED

These groups appear in human stem cell studies. Blood pressure, metabolic control, cardiovascular risk and penile blood flow may still change what is appropriate for you.

After prostate surgery or nerve injury

Small early studies have included post-prostatectomy ED. Results from selected participants cannot be applied to every surgical or nerve-related case.

Hormonal, medication or mixed causes

A history, examination and selected tests should identify treatable contributors first. Stem cell research does not replace correction of a known cause.[4]

Unclear or changing symptoms

If the cause is not clear, start with a proper ED work-up rather than choosing a procedure first. Symptoms, medicines, morning erections, surgery history and prior response all matter.

Where the evidence is most relevant

Most participants in the 2025 review had moderate-to-severe organic ED and many had not responded to first-line medicines or injections. Several trials focused on diabetes or post-prostatectomy ED. The findings are much less applicable to mild, primarily psychogenic, medication-related or otherwise reversible ED.[2]

Do not skip cardiovascular review

The AUA advises that men with ED be counseled that ED is a risk marker for underlying cardiovascular disease and other health conditions. If ED is new, worsening or unexplained, the medical review should not focus only on sexual function.[1]

Before any decision

Five things worth having clear in your records

03Records

NIDDK notes that an ED work-up may cover medical, sexual and mental-health history, a physical exam, lab tests and selected imaging. The exact work-up depends on the person.[4]

01
Onset and pattern

How long, how often, morning erections and whether the problem is consistent or situational.

02
Health and medication history

Diabetes, vascular disease, surgery, nerve injury, hormones and medicines that may affect erectile function.

03
Previous ED options

What you tried, dose or method, response, side effects and why you stopped or changed it.

04
Relevant test results

Recent laboratory results and any penile Doppler or other testing already requested by your physician.

05
Your actual goal

Better rigidity, more reliable response, less dependence on rescue options or another clearly defined functional goal.

Blood testsSelected laboratory testing can look for medical or hormonal contributors suggested by your history.
Penile ultrasoundShows penile blood flow when vascular function needs closer assessment.
Nocturnal erection testMay help show whether normal erections still occur during sleep.
Injection testChecks erection response after an intracavernosal medicine is given by a health professional.[4]
What the numbers actually show

Concrete human results — with the limitations beside them

04Results

Statistical improvement doesn’t automatically mean normal erectile function, medication independence or a permanent result. The most useful reading is the size of the change, who was studied, whether there was a control group and what happened later.

Six months is the strongest pooled time point.

The 2025 meta-analysis found significant 6-month improvement in several outcomes, but only 2–3 studies contributed to most pooled endpoints and heterogeneity reached 71.2% for some measures.[2]

Regenerative medicine research data review related to erectile dysfunction
Randomized diabetic trial
20 men: 10 stem cell, 10 saline

At 6 months, mean IIEF-5 improved in the cell-therapy group and was almost unchanged with saline. The penile Doppler measures did not show a statistically significant between-group difference.

IIEF-5: 7.2 → 10.6
Saline: 7.2 → 7.3
Between groups: P=0.02
PSV between groups: P=0.25. No injection-related complications were reported at 6 months.[9]
Post-prostatectomy trial
21 men after prostate surgery

In the continent subgroup, median IIEF-5 improved at 6 months and then eased back. A patient-level outcome was also reported: 8 of 15 continent men said erectile function was sufficient for intercourse at 12 months.

IIEF-5: 6 → 11 → 9
baseline → 6 → 12 months
8/15 (53%)
sufficient for intercourse at 12 months in the continent subgroup. This was an open-label phase I study, not proof of a general success rate.[9]
24-month diabetic follow-up
8 men, two autologous BM-MSC injections

The clearest lesson is durability. Mean scores peaked at 6 months, were lower at 12 months and were back near baseline by 24 months.

IIEF-5: 10.4 → 17.9 → 15.1 → 10.6
baseline → 6 → 12 → 24 months
EHS: 1.5 → 3.5 → 3.0 → 1.5
At 24 months, IIEF-5 and EHS were not significantly different from baseline. No serious intervention-related adverse event was reported; minor local short-term events were treated conservatively.[5]
2025 randomized diabetic trial
33 men with refractory diabetic ED

Participants were randomized 1:1:1 to placenta-derived MSCs, low-intensity shock-wave therapy, or the combination. The strongest reported 6-month result came from the combined group, so it cannot be attributed to stem cells alone.

70%
of the combined group had EHS >2 at 6 months.
22.20 min
median total erection time in the combined group. No severe adverse events were reported; mild local pain resolved within one week. The study was small and follow-up was 6 months.[10]
How to read the scores

These scales help show whether a numerical change may also represent a meaningful functional change for a patient.

IIEF-55–7 severe · 8–11 moderate · 12–16 mild-to-moderate · 17–21 mild · 22–25 no ED.
EHS0–4 scale. Score 3 means hard enough for penetration but not fully rigid; score 4 means completely hard and fully rigid.[5]
1MEarly safetyLocal reactions and early functional change may be recorded.
3MEarly responseIIEF, EHS and Doppler outcomes are commonly reassessed.
6MBest pooled dataCurrent meta-analysis has its clearest pooled efficacy signal here.
12MDurabilitySome studies show that part of the earlier gain can decline.
24MLimited long dataLong follow-up exists, but in very small open-label populations.
IIEF-5 SMD 1.23

At 6 months, pooled IIEF-5 change was significant (95% CI 0.77–1.70), but only two studies contributed to this estimate.[2]

EDV p=0.868

End-diastolic velocity was not significantly different from baseline at 6 months in the pooled analysis, showing that not every vascular measure improved.[2]

Where stem cell research stands

Compare research options against established ED care

05Compare

Current ED care may cover treating the underlying cause, counselling when relevant, PDE5 inhibitors, local medicines, vacuum devices and surgery for selected patients.[6]

Option
Current role
What matters
PDE5 inhibitors
Established
Contraindications, cardiovascular status, dose, response and side effects.
Vacuum or local medicine
Established
Ease of use, tolerability and reliable functional response.
Penile prosthesis
Established
Suitability, surgical risks, recovery and device expectations.
Stem cell intervention
Investigational
Cell source, processing, study design, safety plan, follow-up and alternatives.[1]
Cost and commitment

There is no valid standard price for stem cell ED care

06Costs

Published ED studies use different cell sources, processing methods, doses and schedules. A price only makes sense when the exact protocol and what’s included are written down.[3]

Regenerative medicine cell processing and cost planning for patient decision support
01Initial evaluationRecord review, consultation and any tests required before eligibility is decided.
02Cell sourceAutologous or donor source, collection requirements and what material is actually used.
03ProcessingPreparation, culture or other processing, testing and quality-control steps.
04Administration planPlanned dose, route, number of administrations and whether repeat procedures are expected.
05Follow-upWhich visits, IIEF/EHS checks, imaging or other monitoring are included and for how long.
06ExclusionsMedicines, extra testing, translation, travel or complication-related costs not included in the headline figure.
Do not compare headline prices alone.

General self-pay regenerative medicine prices in Japan vary widely—they aren’t an ED-specific benchmark.

See our Japan stem cell cost guide for the quote components that should be checked.

Help Me Compare the Details
What safety data actually tells us

Know what should be clear before you pay

07Safety

The 2025 BMC review found mainly mild short-term events in the small published trials, but it stressed that rare complications can’t be ruled out without larger and longer studies. Separately, the U.S. FDA warned in May 2026 that unapproved human cell or tissue products that require approval may expose consumers to serious harm because quality, safety, purity and potency aren’t verified.[2][7]

4trials in the review reported no treatment-related adverse effects.
4trials reported minor local effects such as discomfort, pain, redness, swelling or itching.
2 + 1in one study: 2 patients had minimal redness/swelling and 1 developed a small fibrous plaque without curvature.[2]
Exact cell source and processingYou should know what is being administered and how it is prepared.
No guaranteed outcome languageCurrent evidence cannot support a guaranteed cure, permanent result or medication independence.
Written follow-up planKnow who checks outcomes, when they are checked and how adverse events are handled.
Useful checks for care in Japan

Regulatory status, a filed regenerative medicine provision plan and product approval are different concepts. Use the supporting guides below to understand what to verify rather than treating one registration or filing as proof that an intervention works.

Where we come in

Turn scattered records into a clearer next step

08Support

We help you organize your history, make sense of published evidence, prepare practical questions, coordinate consultations and translate medical information—so you can make a better-informed decision.

01Organize your recordsSymptoms, diagnoses, medicines, tests and previous ED response in one concise summary.
02Match the right questionsIdentify what needs clarification about evidence, protocol, alternatives, cost and follow-up.
03Coordinate the discussionHelp prepare materials and arrange the consultation process based on the records you provide.
04Translate key informationSupport clear communication of symptoms, physician explanations and the next steps you receive.

Our support is informational and coordination-based. Diagnosis, eligibility and treatment decisions stay with licensed physicians.

Medical information organization and consultation coordination for patients exploring regenerative medicine
Questions worth answering

Before you commit time or money

10FAQ
Regenerative medicine evidence review for patients considering erectile dysfunction research options
Is stem cell therapy an established ED treatment?

No. Current urology guidance classifies intracavernosal stem cell therapy as investigational. Human studies report promising functional signals, but protocols remain inconsistent and stronger controlled long-term evidence is needed.[1]

Which patients have actually been studied?

Published human research includes selected organic ED populations such as diabetes-related ED and ED after prostate surgery, using several different cell sources. Those study groups are too small and varied to create a universal candidacy rule.[3]

How long can improvement last?

There is no reliable single duration. Six-month improvements appear in pooled analyses, while some longer studies show that benefit can decline. Your expectation should be tied to the exact protocol and follow-up evidence, not a permanent-result promise.[2][5]

What does a 3–5 point IIEF-5 improvement actually mean?

It may move a patient into a less severe score category, but it does not guarantee normal function or intercourse without other support. For example, one randomized diabetic trial improved from 7.2 to 10.6 at 6 months—an improvement, but still within the moderate-ED range on the IIEF-5 scale.[2]

Does the published evidence apply to mild or mainly psychological ED?

Not well. Most stem-cell trial participants had organic, often moderate-to-severe or treatment-refractory ED, with diabetes and post-prostatectomy ED commonly represented. The evidence is much less applicable when a reversible medication effect, hormonal issue, anxiety or another treatable contributor is the main driver.[2][8]

Can I stop my current ED medicines if I consider stem cells?

Do not stop prescribed medicines on your own. A licensed physician should review your current response, contraindications and alternatives before any change. NIDDK specifically advises discussing medication changes with a health professional.[6]

What should follow-up look like after a research procedure?

There is no universal schedule because protocols differ. One 24-month phase 2 study checked participants at 1, 3, 6, 12 and 24 months. A written plan should say when IIEF-5 or EHS will be repeated, whether penile Doppler is needed, and who to contact for persistent pain, swelling, redness, new curvature or other concerns.[5]

Should new ED trigger a cardiovascular check?

It can be important. The AUA states that ED is a risk marker for underlying cardiovascular disease and other health conditions. New or worsening ED should therefore be reviewed in the context of blood pressure, diabetes, lipids, smoking history, medicines and overall cardiovascular risk rather than treated only as a sexual-function problem.[1]

What should I send first?

Start with a short history: age, ED duration and pattern, diabetes or cardiovascular history, pelvic or prostate surgery, current medicines, recent relevant tests, and which ED options you have already tried with the result and side effects.

Start with what you already have

Turn your records into a clearer next step

Send your main history, current medicines, previous ED options and relevant test results. We’ll help organize the information, prep practical questions, coordinate the discussion and support medical translation.

WhatsApp +81-8070161366LINE +81-8075357788

Our support is informational and coordination-based. Diagnosis, eligibility and treatment decisions remain with licensed physicians.