Erectile DysfunctionPhase 4NCT07642505
L-Citrulline and Tadalafil for Mild to Moderate Erectile Dysfunction
A Phase 4 study testing L-Citrulline and Tadalafil in people with Erectile Dysfunction, run by Beni-Suef University at 1 site in Egypt.
Trial summary
Erectile dysfunction is a common male sexual health problem that may affect quality of life and sexual relationships. Tadalafil 5 mg once daily is an established oral treatment for erectile dysfunction. Read more about this study
- Who is it for?
- Ages 30 to 70 years, men only
- Conditions the study is for
- Erectile Dysfunction
- What is being tested?
- L-Citrulline and Tadalafil
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 133 participants
- Where
- 1 siteEgypt
- Study dates
- 8 Jun 2026to Dec 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 30 to 70 years
- Men only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male patients aged 30 to 70 years.
- Erectile dysfunction for at least 3 months.
- Mild to moderate erectile dysfunction, defined by International Index of Erectile Function-Erectile Function domain score from 11 to 25.
- Stable sexual relationship during the study period.
- Willingness to attempt sexual activity during the study period.
- Ability to complete study questionnaires and attend follow-up visits.
- Written informed consent.
Who cannot join
- Severe erectile dysfunction, defined by International Index of Erectile Function-Erectile Function domain score of 10 or less.
- Current nitrate or nicorandil use.
- Contraindication or hypersensitivity to tadalafil or L-citrulline.
- Unstable cardiovascular disease, unstable angina, recent myocardial infarction or stroke, uncontrolled hypertension, or high-risk arrhythmia.
- Severe hepatic impairment.
- Severe renal impairment.
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- Untreated hypogonadism requiring hormonal treatment.
- Hyperprolactinemia or uncontrolled endocrine disorder.
- Major neurogenic erectile dysfunction, spinal cord injury, or previous radical pelvic surgery causing severe erectile dysfunction.
- Significant Peyronie's disease preventing intercourse.
- Active major psychiatric illness impairing reliable assessment.
- Use of phosphodiesterase type 5 inhibitors, intracavernosal injection therapy, vacuum device therapy, testosterone therapy, L-arginine, L-citrulline, or erectile dysfunction nutraceuticals during the washout period before randomization.
- Participation in another clinical trial during the previous 3 months.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Egypt1 site, 1 recruiting
- Recruiting
Department of Urology- Beni-Suef University Hospitals
Banī Suwayf, Beni Suweif Governorate, 02456
Hany F Badawy, MD, 01149525028, HANYFATHY86@GMAIL.COM
HANYFATHY86@GMAIL.COM
About this study
Official title: L-Citrulline Versus Tadalafil Versus Combination Therapy in Mild to Moderate Erectile Dysfunction: A Prospective Randomized Trial
Erectile dysfunction is a common male sexual health problem that may affect quality of life and sexual relationships. Tadalafil 5 mg once daily is an established oral treatment for erectile dysfunction. L-citrulline is an oral nitric oxide pathway supplement that may improve erectile function by increasing L-arginine availability.
This randomized trial will compare three oral treatment regimens in men with mild to moderate erectile dysfunction: L-citrulline 1500 mg/day, tadalafil 5 mg/day, and the combination of L-citrulline 1500 mg/day plus tadalafil 5 mg/day. Participants will receive treatment for 12 weeks and will be followed at baseline, week 4, week 8, and week 12.
The primary outcome will be the change in the International Index of Erectile Function-Erectile Function domain score from baseline to 12 weeks. Secondary outcomes will include changes in IIEF-5/SHIM score, Erection Hardness Score, SEP diary outcomes, treatment adherence, adverse events, and treatment discontinuation.
Read the detailed description
This is a prospective, randomized, three-arm, parallel-group, active-controlled clinical trial conducted at the Urology outpatient clinics of the Department of Urology, Faculty of Medicine, Beni-Suef University, Egypt.
Adult men with mild to moderate erectile dysfunction will be enrolled after written informed consent. Eligible participants will be randomized in a 1:1:1 ratio to receive one of three oral treatment regimens for 12 weeks: L-citrulline 1500 mg/day, tadalafil 5 mg/day, or combination therapy with L-citrulline 1500 mg/day plus tadalafil 5 mg/day.
The preferred design is double-blind and double-dummy, using active and matching placebo preparations when available. Participants will be assessed at baseline, week 4, week 8, and week 12. Baseline assessment will include medical and sexual history, review of comorbidities and medications, physical examination, relevant laboratory tests, and validated erectile function questionnaires.
The primary endpoint is change in the International Index of Erectile Function-Erectile Function domain score from baseline to 12 weeks. Secondary endpoints include change in IIEF-5/SHIM score, change in Erection Hardness Score, proportion of patients achieving Erection Hardness Score grade 4, change in affirmative SEP-3 responses, adherence, treatment-emergent adverse events, and discontinuation due to adverse events.
- Conditions
- Erectile Dysfunction
- Being tested
- L-Citrulline, Tadalafil, L-Citrulline Placebo, Tadalafil Placebo
- Keywords
- L-citrulline, Tadalafil, International Index of Erectile Function
- Medical subject headings
- Erectile Dysfunction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-CitrullineDrug
Oral L-citrulline 1500 mg/day administered for 12 weeks as an active oral nitric oxide pathway supplement for men with mild to moderate erectile dysfunction.
TadalafilDrug
Oral tadalafil 5 mg once daily administered for 12 weeks as active phosphodiesterase type 5 inhibitor therapy for men with mild to moderate erectile dysfunction.
L-Citrulline PlaceboDrug
Oral placebo preparation matching L-citrulline, administered for 12 weeks as part of the double-dummy design
Tadalafil PlaceboDrug
Oral placebo preparation matching tadalafil, administered for 12 weeks as part of the double-dummy study design.
| Study group | Role | What they receive |
|---|---|---|
| L-Citrulline | Experimental | Participants assigned to this arm will receive oral L-citrulline 1500 mg/day for 12 weeks. In the double-dummy design, participants will receive active L-citrulline plus tadalafil placebo. Receives: Drug: L-Citrulline; Drug: Tadalafil Placebo |
| Tadalafil | Active comparator | Participants assigned to this arm will receive oral tadalafil 5 mg once daily for 12 weeks. In the double-dummy design, participants will receive active tadalafil plus L-citrulline placebo. Receives: Drug: Tadalafil; Drug: L-Citrulline Placebo |
| L-Citrulline Plus Tadalafil | Experimental | Participants assigned to this arm will receive combination oral therapy with L-citrulline 1500 mg/day plus tadalafil 5 mg once daily for 12 weeks. Receives: Drug: L-Citrulline; Drug: Tadalafil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in International Index of Erectile Function-Erectile Function Domain Score
Change in the International Index of Erectile Function-Erectile Function domain score from baseline to week 12. The Erectile Function domain score ranges from 1 to 30, with higher scores indicating better erectile function. A greater positive change indicates greater improvement in erectile function
Measured: Baseline to 12 weeks
Secondary outcomes (3)
Change in International Index of Erectile Function-5 Score
Change in the International Index of Erectile Function-5 score, also known as the Sexual Health Inventory for Men score, from baseline to week 12. The score ranges from 5 to 25, with higher scores indicating better erectile function. A greater positive change indicates greater improvement.
Measured: Baseline to 12 weeks
Treatment Adherence
Percentage of prescribed study medication doses taken during the 12-week treatment period, assessed by patient report and treatment accountability at follow-up visits. Higher percentages indicate better adherence
Measured: From treatment initiation to 12 weeks
Proportion of Participants Achieving Erection Hardness Score Grade 4
Percentage of participants achieving Erection Hardness Score grade 4 at week 12. Grade 4 indicates that the penis is completely hard and fully rigid.
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Jun 2026
- Study start8 Jun 2026
- Primary completionNov 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Erectile DysfunctionStudies of the same condition, open and under way.
- More trials run by Beni-Suef UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomized in a 1:1:1 ratio to one of three parallel treatment arms: L-citrulline 1500 mg/day, tadalafil 5 mg/day, or combination therapy with L-citrulline 1500 mg/day plus tadalafil 5 mg/day. Each participant will receive the allocated oral treatment for 12 weeks, with follow-up visits at baseline, week 4, week 8, and week 12.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 133 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Beni-Suef University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Hany Fathy Badawy, MD, Beni-Suef University
- Investigators
- Hany F Badawy, Principal investigator, Faculty of medicine Beni-Suef University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07642505
- Sponsor's protocol ID
- FMBSUREC-07062026g-Badawy
- Status last verified
- Jun 2026
- First submitted
- 8 Jun 2026
- Last updated
- 12 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because the study includes sensitive individual-level sexual health data and treatment-related clinical information. Only aggregated, de-identified results will be reported in publications or presentations. Any future sharing of de-identified participant-level data would require additional approval from the Research Ethics Committee, Faculty of Medicine, Beni-Suef University.
Study at a glance
From the registry record, last updated by the sponsor on 12 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- L-Citrulline Versus Tadalafil Versus Combination Therapy in Mild to Moderate Erectile Dysfunction: A Prospective Randomized Trial
- ClinicalTrials.gov ID
- NCT07642505
- Acronym / sponsor ID
- FMBSUREC-07062026g-Badawy
- Conditions
- Erectile Dysfunction
- Keywords
- L-citrulline, Tadalafil, International Index of Erectile Function
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 133 participants (estimated)
- Lead sponsor
- Beni-Suef UniversityUniversity, hospital or other
- Study start
- 8 Jun 2026 (actual)
- Primary completion
- Nov 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 11 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Erectile dysfunction is a common male sexual health problem that may affect quality of life and sexual relationships. Tadalafil 5 mg once daily is an established oral treatment for erectile dysfunction. L-citrulline is an oral nitric oxide pathway supplement that may improve erectile function by increasing L-arginine availability.
This randomized trial will compare three oral treatment regimens in men with mild to moderate erectile dysfunction: L-citrulline 1500 mg/day, tadalafil 5 mg/day, and the combination of L-citrulline 1500 mg/day plus tadalafil 5 mg/day. Participants will receive treatment for 12 weeks and will be followed at baseline, week 4, week 8, and week 12.
The primary outcome will be the change in the International Index of Erectile Function-Erectile Function domain score from baseline to 12 weeks. Secondary outcomes will include changes in IIEF-5/SHIM score, Erection Hardness Score, SEP diary outcomes, treatment adherence, adverse events, and treatment discontinuation.
Detailed description
This is a prospective, randomized, three-arm, parallel-group, active-controlled clinical trial conducted at the Urology outpatient clinics of the Department of Urology, Faculty of Medicine, Beni-Suef University, Egypt.
Adult men with mild to moderate erectile dysfunction will be enrolled after written informed consent. Eligible participants will be randomized in a 1:1:1 ratio to receive one of three oral treatment regimens for 12 weeks: L-citrulline 1500 mg/day, tadalafil 5 mg/day, or combination therapy with L-citrulline 1500 mg/day plus tadalafil 5 mg/day.
The preferred design is double-blind and double-dummy, using active and matching placebo preparations when available. Participants will be assessed at baseline, week 4, week 8, and week 12. Baseline assessment will include medical and sexual history, review of comorbidities and medications, physical examination, relevant laboratory tests, and validated erectile function questionnaires.
The primary endpoint is change in the International Index of Erectile Function-Erectile Function domain score from baseline to 12 weeks. Secondary endpoints include change in IIEF-5/SHIM score, change in Erection Hardness Score, proportion of patients achieving Erection Hardness Score grade 4, change in affirmative SEP-3 responses, adherence, treatment-emergent adverse events, and discontinuation due to adverse events.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- Participants will be randomized in a 1:1:1 ratio to one of three parallel treatment arms: L-citrulline 1500 mg/day, tadalafil 5 mg/day, or combination therapy with L-citrulline 1500 mg/day plus tadalafil 5 mg/day. Each participant will receive the allocated oral treatment for 12 weeks, with follow-up visits at baseline, week 4, week 8, and week 12.
| Arm | Type | Receives |
|---|---|---|
| L-Citrulline | Experimental | Drug: L-Citrulline, Drug: Tadalafil PlaceboParticipants assigned to this arm will receive oral L-citrulline 1500 mg/day for 12 weeks. In the double-dummy design, participants will receive active L-citrulline plus tadalafil placebo. |
| Tadalafil | Active comparator | Drug: Tadalafil, Drug: L-Citrulline PlaceboParticipants assigned to this arm will receive oral tadalafil 5 mg once daily for 12 weeks. In the double-dummy design, participants will receive active tadalafil plus L-citrulline placebo. |
| L-Citrulline Plus Tadalafil | Experimental | Drug: L-Citrulline, Drug: TadalafilParticipants assigned to this arm will receive combination oral therapy with L-citrulline 1500 mg/day plus tadalafil 5 mg once daily for 12 weeks. |
Who may qualify
- Ages
- 30 to 70 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Male patients aged 30 to 70 years.
- Erectile dysfunction for at least 3 months.
- Mild to moderate erectile dysfunction, defined by International Index of Erectile Function-Erectile Function domain score from 11 to 25.
- Stable sexual relationship during the study period.
- Willingness to attempt sexual activity during the study period.
Key exclusion criteria (13 listed)
- Severe erectile dysfunction, defined by International Index of Erectile Function-Erectile Function domain score of 10 or less.
- Current nitrate or nicorandil use.
- Contraindication or hypersensitivity to tadalafil or L-citrulline.
- Unstable cardiovascular disease, unstable angina, recent myocardial infarction or stroke, uncontrolled hypertension, or high-risk arrhythmia.
- Severe hepatic impairment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| L-CitrullineOral L-citrulline 1500 mg/day administered for 12 weeks as an active oral nitric oxide pathway supplement for men with mild to moderate erectile dysfunction. | Drug | L-Citrulline, L-Citrulline Plus Tadalafil |
| TadalafilOral tadalafil 5 mg once daily administered for 12 weeks as active phosphodiesterase type 5 inhibitor therapy for men with mild to moderate erectile dysfunction. | Drug | L-Citrulline Plus Tadalafil, Tadalafil |
| L-Citrulline PlaceboOral placebo preparation matching L-citrulline, administered for 12 weeks as part of the double-dummy design | Drug | Tadalafil |
| Tadalafil PlaceboOral placebo preparation matching tadalafil, administered for 12 weeks as part of the double-dummy study design. | Drug | L-Citrulline |
Primary outcome
Change in International Index of Erectile Function-Erectile Function Domain Score
Time frame: Baseline to 12 weeks
Change in the International Index of Erectile Function-Erectile Function domain score from baseline to week 12. The Erectile Function domain score ranges from 1 to 30, with higher scores indicating better erectile function. A greater positive change indicates greater improvement in erectile function
3 secondary outcomes
Change in International Index of Erectile Function-5 Score
Time frame: Baseline to 12 weeks
Treatment Adherence
Time frame: From treatment initiation to 12 weeks
Proportion of Participants Achieving Erection Hardness Score Grade 4
Time frame: 12 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Jun 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared because the study includes sensitive individual-level sexual health data and treatment-related clinical information. Only aggregated, de-identified results will be reported in publications or presentations. Any future sharing of de-identified participant-level data would require additional approval from the Research Ethics Committee, Faculty of Medicine, Beni-Suef University.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Hany F Badawy principal investigator
Faculty of medicine Beni-Suef University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing L-Citrulline and Tadalafil in people with Erectile Dysfunction, run by Beni-Suef University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 12 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Hany F Badawy, MD (+201149525028, HANYFATHY86@GMAIL.COM), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in International Index of Erectile Function-Erectile Function Domain Score (time frame: Baseline to 12 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Jun 2026.